Paper Set

NUS/1267 Third Year B.E.(Prod.) Examination WORK STUDY Paper 3 P 2 SECTION A a) What is productivity ? What is the relationship between standard of living and Productivity ? How the productivity of industry can be increased ? 8 b) What is work study ? What is the contribution of F.W. Taylor and F.B. Gilbreth in the development of Work-Study ? 6 OR 2. a) Define work-study. What is the need of work study ? 5 b) What is the importance of human factor in the adaptation of work study ? 4 c) What is ‘basic work content ? How the total time of job is made up ? 5 3. a) Define ‘Method Study’ What are its objectives ? Explain the procedure of Method Study. 8 b) Draw the various process chart symbols and explain their meaning. 5 OR 4. a) Explain flow process chart-material type with suitable example. 6 b) List out the various charts, diagrams and graphs used for Method Study. 3 c) Which points should be considered while selecting a job for Method Study ? 4 5. a) Explain two handed process chart with an example. 5 b) Explain the construction, uses and drawbacks of string diagram. 8 OR 6. a) Explain multiple-activity chart with example. 5 b) Explain construction, uses and draw backs of cyclegraph and travel chart. 8 SECTION B 7. a) Define ‘Work-Measurement’ Explain the procedure of work measurement. 6 b) List out various Work Measurement techniques 3 c) What is the Meaning of qualified worker ? How the worker is selected for time-study ? 4 OR 8. a) Discuss the objectives of work-measurement. 6 b) What is pre-determined time-standard ? What are its applications ? 7 9. a) An industrial job involves five operations and related data is given below. 8 Assuming Rest and personal allowances as 10% and contingencies as 2% of the basic time. Find standard time for completing the job. Operation Number Observed Time Standard Rating (0 – Remarks if any (Min.) 100) 1 0.20 85 2 0.32 95 3 0.26 90 4 0.35 100 5 3.05 80 Observed time is for transporting 5 jobs 1.

b) List out the equipments required for time study. c) What are the applications of time study ? OR 10. a) Explain the procedure of stop watch time study. b) Define :i) Standard time. ii) Basic time. 2 c) What are allowances ? What are different types of allowances ? Explain any one. 11. a) Why training is needed to personnel while introducing work study ? b) What are incentives ? Explain following wage incentive plans. i) Halsey plan. ii) Roman plan OR 12. a) Explain the steps involved in developing standard data. b) What are the steps to be taken to increase the productivity ?

2 4 7

5 6 7 7 6

N-045

S.N.P.- 898 Third Year B. E. (Prod) Examination WORK STUDY Paper : 3 – P – 2 Section : A & B Max. Marks : 80 SECTION – A

1.

A) Good relations must be established before work-study is conducted. Explain.

7

B) How productivity of material can be increased through saving at various stages of production.

7

OR 2.

A) What do you mean by basic work content ? How ineffective time is added due to worker ?

7

B) Why workers oppose the application of work study in industry ? 3.

7

A) Name various process charts used in ‘Method-Study’ and explain any one of them in detail.

7

B) Explain the following : i)

Flow diagram

ii)

Travel chart

6

OR 4.

A) ‘Critical examination is the crux of method study’.

7

Discuss. B) Discuss the factors to be considered while selecting the work for method – study. 5.

6

A) What is SIMO chart ? Explain with an example.

7

B) What is ‘Memomotion’ study ? State its application with example.

6

OR 6.

A) What are ‘Therbligs’? Define and draw following therbligs. i) ii) iii)

Assembly Inspect Plan

6

B) Define ‘Micro-motion’ study. Explain the steps in micro-motion study. SECTION – B 7.

7

A) Define ‘Work-measurement.’ Explain the various techniques of work-measurements.

7

B) What is pre-determined time-standard ? What are its applications ? 6 OR 8.

A) Discuss the objective of work-measurement.

6

B) What do you mean by ‘Standard data’ ? State its application with suitable example. 9.

7

A) Explain the steps in making stop-watch time study.

7

B) What are the reasons for breaking the jobs into elements in time-study? 7 OR 10.

A) An industrial job involves three operations and related data is given below. Assuming rest and personnel allowances as 10 % and contingencies as 2 % of basic time. Find standard time for completing job.

8

Operation No.

Observed Time

1 2 3

(min) 0.32 0.35 2.10

Standard rating (0-100) 85 95 80

B) What are applications of Time-study ? 11.

6

A) What are the problems in increasing productivity through work study ? 6 B) What are incentives ? Explain following wage incentive plans. i)

Halsey plan

ii)

Rowan plan

7

OR 12.

A) Explain the steps involved in developing standard data. B) What are the steps to be taken to increase the productivity. ***

7

NVD / 1284 Third Year B. E. ( Production Engg. ) Examination WORK STUDY Paper 3 P2 Max. Marks : 80 SECTION – A 1.

a) What is work study ? Explain its need and scope of applications. b) Define Productivity. Discuss the factors responsible for reducing Productivity.

6 7

OR 2.

3.

a) The attitude of the supervisor must be won before work study is conducted. Why ? b) What do you mean by basic work content ? How ineffective time is added due to workers ? a) Discuss the factors to be considered while selecting the work for method study. b) Name the various process charts used in Method study and explain any one of them in detail.

6 7

3 5

OR 4.

5.

a) Define Method study. Explain in detail the various steps involved in systematic methods of improvement. b) Explain the following :i) Flow diagram. ii) Travel chart. a) Discuss principles of motion economy as applied to human body. b) Define method study. Explain in detail the various steps involved in systematic methods of improvement. c) What is chronocyclegraph ?

7 6 5 6 3

OR 6.

a) Explain the term templates and models with their advantages and disadvantages. b) What is memomotion study ? State its applications. c) What is SIMO chart ? Explain with an example.

6 3 5

7.

SECTION – B a) Define work Measurement. Explain is brief the procedure of work measurement. b) State the applications of standard data. c) ‘Management is responsible for the stoppages and the breakdowns. This can be found our with the help of work measurement. Explain. OR

5 3 5

8.

a) What are the applications of work measurement ? b) Enlist the techniques of work measurement with short explanation.

5 8

9.

a) What are the reason for breaking the job into elements in time study ? b) An industrial job involves three operations and the related data is given below. Assuming Rest and personal allowances as 10% and contingencies as 2% of the basis time find the standard time for completing the job. Operation No. Observed Time Standard Rating (min.) (0-100) 1 0.32 85 2 0.35 95 3 2.10 80 c) What are the applications of time study ? OR

5

10.

a) Discuss the steps involved in the procedure of stop watch time-study. b) What is performance rating ? Explain various systems of rating.

6 7

11.

a) What is work sampling and how it works in Industries ? 5 b) What are the problems in increasing productivity through work study? 5 c) What are incentives ? List out the objectives of a sound wage incentive plan. 4 OR

12.

a) A work sampling study was conducted for 100 hours in the machine shop in order to estimate the standard time. The total number of observations recorded were 2500. No working activity could be noticed for 400 observations. The ratio between manual and machine elements was 2:1. Average rating factor was estimated as 1.20 and the total number of articles produced during the study period were 6000. Rest and personal allowances may be taken as 12% of the normal time. Find the standard time. 4 b) Explain the steps involved in developing standard data. c) What steps can be taken to increase the productivity ? ***

5 3

4 3

DVW – 1182/STS-5096 Faculty of Engineering & Technology Third Year B.E.(Production Engg.) Examination WORK STUDY Paper : 3 P 2 Sections A & B Maximum Marks :80 1.

2.

3.

4.

5.

6.

7.

SECTION A (a) What is ‘Work study’ ? Write in brief the basic procedure of work study. (b) How is the total time of a job made up ? OR (a) What is productivity ? What are the factors affecting productivity ? (b) How can the work content be reduced due to the process and the methods ? Define the method study and discuss the following tools used for the purpose : (i) Operation Process Chart. (ii) Flow diagram (iii) Travel Chart (iv) String diagram OR (a) Explain the procedure of method study. (b) How do flow process chart symbols differ from those used for two handed process chart ? (a) What is SIMO chart ? Explain with an example. (b) Distinguish between memomotion and micromotion study. OR (a) What are cyclegraphs and chronocyclegraphs ? (b) Show with the help of two-handed process chart, how productivity can be improved by resequencing the activities of certain operation. SECTION B

7 6 7 6 13

7 6 8 6 6 8

(a) What is ‘Work measurement’ ? Explain its relationship with ‘Method study’. 7 (b) Discuss various application s of ‘Work measurement’. 6

OR

8.

9. 10.

11.

12.

(a) ‘Management is responsible for the stoppages and the breakdowns.’ This can be found out with the help of work measurement. Explain. 5 (b) Enlist the techniques of work measurement with short explanation. 8 Discuss the procedure for timing each element by stop watch in detail. 13 OR (a) What is performance rating ? Why it is necessary ? Discuss various systems of rating. 8 (b) Why it is necessary to break down the job into elements ? 5 (a) Explain the steps involved in developing standard data. 5 (b) Define the term Work Sampling. What are its applications ? 5 (c) List out the objectives of a sound wage incentive plan. 4 OR A work sampling study was conducted for 100 hrs.in the machine shop in order to estimate the standard time. The total number of observations recorded were 3000. Number of working activity could be noticed for 450 observations. The ratio between manual and machine elements was 2:1. Average rating factor was estimated as 1:15 and the total number of articles produced during the study period were 7,000. Rest and Personal allowances may be taken as 12% of the normal time. Find Standard time. 14 ***

STD-1109 Faculty of Engineering & Technology Third Year B.E. (Production Engg.) Examination WORK STUDY Paper 3 P 2 Sections A & B Maximum Marks – 80 1.

2.

3.

4.

5.

6.

7.

SECTION A (a) Define Work Study. What is the contribution of F.W. TAYLOR to work study ? 7 (b) How work study is useful for Management, Labour Society and Industrial Productivity ? OR (a) Define Productivity. Discuss the factors responsible for reducing Productivity. (b) What are the problems likely to be encountered in implementation of work study ? How should they be dealt with ? (a) Name the various process charts used in Method Study and explain any one of them in details. (b) Define Method Study. Explain in detail the various steps involved in systematic methods of improvement. OR (a) Define Process Charts. What are the symbols used to record different types of events ? (b) Prepare a outline process chart of making a Dovetail joint in a pattern making shop. (a) Describe cyclograph and chronocyclograph and explain their use with a neat sketch. (b) List various principles of Motion Economy as applicable to the use of Human body. OR (a) What are the techniques of Micromotion study ? Give the list of various Micromotion study Equipment. (b) What is a string diagram ? Draw a string diagram of a work of your choice. SECTION B (a) Assuming that the total observed time for an operation of assembling an Electronic Switch is 1.00 minute. If the rating 120% find the normal time. If the allowance of 10% is allowed for the operation, determine the standard time. (b) Define Work Measurement and what are the fundamental concepts of work measurement. OR

7 7 7 6 7 6 7 6 7 7 6

5 8

8. 9.

10.

11.

12.

(a) What are the various systems in use of P.T.S. ? Explain one most popular amongst them. (b) What do you mean by Qualified Worker ? (a) Give brief accounts of all the main Rating systems. (b) What is elemental breakdown in time study ? Give its advantages. OR (a) Discuss the various factors which are taken into consideration while selecting an operator for time study. 5 (b) Explain the following terms :(i) Rating (ii) Fatigue allowance (iii) Standard time. (a) Give the salient features of sampling procedure in work sampling. (b) A work sampling study showed that 20% of a work, week of 48 hours was consumed by available delays. If each time a work sampling observation was made, the operator was rated and the average of such ratings was 110%. If 100 units were produced by the operator in that period, calculate the standard time. OR (a) What is work sampling and how it works in Industries ? (b) Enumerate the uses and limitations of work sampling. ***

9 4 7 7

9 7

6 8 5

GOV-894/VMT-7868 WORK STUDY 1.

2.

3.

4.

5.

6.

7.

SECTION – A (a) Increased productivity lead to higher standard of living. Justify.5 (b) Define Ineffective time. (c) Which are the factors reducing productivity ? OR (a) What is work study ? What is the contribution of F.W. Taylor to work study ? (b) Explain the procedure for work study ? What are the advantage of work study ? (a) Define method study. What are the objectives of method study of the procedure for carrying out method study ? (b) Name the various process chart used in method study and explain one of them in detail. OR (a) Which factors are to be considered while selecting the work for method study ? (b) Explain the principle of motion economy as applied to Human body. (c) Explain material flow process chart with suitable example. (a) Define multiple activity chart. Explain it with a suitable example. (b) Define and explain ‘Simo-chart’. (c) Distinguish between memomotion and micromotion study. OR (a) Define and explain cycle-graph with neat sketch. (b) Explain the steps involved in the process of micromotion study. (c) Define and draw symbols of following therbligs :(i) Unavoidable delay (ii) Transport loaded (iii) Plan (iv) Rest (v) Assemble (vi) Find SECTION B (a) In an eight-hour day it was found that the normal time was 400 minutes. Assuming that the remaining time is meant for rest and personal needs. Determine the standard time/article, if the normal time/article is 1.5 min. Also find the no. of articles produced/day. (b) Define allowances. Explain : (i) Personal and Rest Allowance (ii) Special Allowance. (c) What do you mean by a Qualified worker ?

2 6 7 6 8 5 5 5 3 5 4 4 3 5

5

5 5 3

8.

9.

10.

11.

12.

OR (a) Define work measurement. What is the procedure for work measurement ? (b) Assume you are the Supervisor. Work measurement is to be introduced into your department. How would you explain to your men the technique of work measurement and how it might effect them ? (a) Describe the advantages and disadvantages of both snap-back and continuous method of using a stop watch. (b) How standard time is calculated ? (c) What is Rating in time study ? Why is it done ? OR (a) What are the techniques of work measurement ? Explain each of them briefly. (b) What is the purpose of work measurement ? Explain the uses of work measurement. (a) How the sample size is decided ? (b) Define Standard Data. How is the standard data developed ? (c) What are the limitations of work sampling ? OR (a) How activity sampling can be used to determine the efficiency of utilization of men and m/c in a machine shop ? How would you use their information ? (b) Define incentives. What are the characteristics of a good incentive plan ? (c) Explain the HALSEY wage incentive plan. ***

6

7 6 3 4 7 6 3 6 4

6 4 3

VSH-674/MHR-5424 WORK STUDY 1.

(a) (b) (c)

2.

(a) (b)

3.

(a) (b)

4.

(a) (b) (c)

5.

(a) (b) (c)

6.

(a)

SECTION A “Work study is one of the most pertaining tool of investigation available to the Management.”. Explain. “Good relation must be established before work study is conducted”. Comment. What do you understand by productivity of materials ? OR Describe Frank Gilbreth contribution to the development of work study. Explain in brief concept of productivity. What is method study ? How will you determine the areas that need method study application in an industry ? What is the difference between flow process chart and Two handed process chart ? Draw flow chart for the activity of cleaning the spark plug of a motorcycle. OR Explain Two handed process chart with suitable example. Explain the principles of motion economy as applied to Human body. What are the different types of flow process chart ?

5 6 2 6 7

7 6 4 6 3

Define Travel Chart ? Explain the procedure for preparing a Travel Chart. 6 What is chronocyclegraph ? 2 Define Therblig’s ? How will you show the following therblig’s:- 5 (i) Assemble (ii) Rest (iii) Inspect (iv) Plan (v) Hold OR In a manufacturing unit two handed process chart is prepared for ‘clamping the job on m/c’ which is as follows :

Left Hand Description To W/P Grasp W/P To Machine Release W/P Idle

I.H. Symbol O O D

R.H. Symbol D D D D O

Right Hand Description Idle on m/c Idle on m/c Idle on m/c Idle on m/c Place W/P in position

Idle To m/c Strait m/c To m/c Stop m/c Turn Handle to unclamp Push away job

D

O O

O D D D D D

Turu Handle to clamp Idle to m/c Idle to m/c Idle on m/c Idle on m/c Idle on m/c

O

D

Idle on m/c

O

Suggest an improved method for the activity based on data obtained from the above chart, so that the motion of both the hands (b) 7.

(a) (b)

8.

(a) (b) (c)

9.

(a) (b) (c)

10.

(a) (b)

11.

(a) (b)

12.

(a) (b) (c)

What is Flow Diagram ? Illustrate it with a suitable example. SECTION B Define work measurement. What are the various techniques used for work measurement ? Explain any one in detail. What is predetermined time standards ? What are its advantage and where is it used ? OR What are the objective of work measurement ? Define Rating. Explain : (i) Synthetic Rating. (ii) Objective Rating. What are the uses of Standard Data ?

7 6

7 6 4 5 4

What is time study ? Which equipments are used for carrying out time study ? 5 What are the steps involved in making a time study ? 5 Can the time study be carried out on any worker ? 3 OR What different allowances are provided to arrive at standard time ? 4 Define rating. Why is it necessary ? Explain the various rating techniques in detail. 9 What do you know by work sampling ? What are its applications ? 6 Explain the following wage incentive plan :(i) ROWAN Plan (ii) HALSEY Plan OR Define ‘Activity Sampling’. 2 Define ‘Standard data’. Also give its application. 5 “Incentives are necessary for smooth and efficient running of a factory.” Discuss. 6 ***

NUS/1278 Third Year B.E. (Production Engg.) Examination METROLOGY AND QUALITY CONTROL SECTION A 1.

(a)

(b)

2.

(a)

(b)

3.

(a)

(b)

4.

(a) (b)

What are fits ? Explain in brief the following types of fits. How they can be achieved ? (i) Selective fit (ii) Push fit (iii) Driving fit (iv) Forced fit (v) Shrinkage fit A limit gauge is required to check the hole 50 H8. The length of the hole is 100 mm. Neglecting the guage tolerance and wear allowance, show the GO and NO GO limit gauges for checking hole as per IS : 919. Given : IT 8 for basic size 50 mm = 39 microns. OR

10

4

Why is it necessary to give a tolerance on an engineering dimension ? Give examples of various types of tolerances.

7

Explain what do you understand by ‘an end standard’ and ‘a line standard’. Sketch and describe international prototype meter and state under which of the above categories this falls. Also discus its disadvantages.

7

Explain the principles of pneumatic gauging by the ‘back pressure’ system. Why is it not used over entire range of pressure ?

7

What are the measures of an angle ? Describe and sketch the principles of clinometer. OR

6

Compare mechanical, comparator and optical comparator. Describe the working of mechanical optical comparator.

6

What is ‘best-size wire’ ? How will you measure effective diameter of external thread using ‘best-size wire ?

7

5.

(a) (b)

6.

(a) (b)

7.

(a) (b)

8.

(a) (b)

9.

(a) (b)

How will you check small threads using ‘Tool – Maker’s Microscope’? Explain. Explain the following in relation to surface texture. (i) Ra Value (ii) Sampling length (iii) Lay OR Explain in detail the working of mechanical roughness instrument. ‘Mecrin’. Discuss about various errors in gear. How will you check composite errors in a spur gear ? SECTION B What do you understand by cost of quality and value of quality ? How to balance them ? State and explain the responsibilities of a Quality Manager. OR Explain the steps in quality control programmes. What are the benefits of statistical quality control ?

7

6 6 7 7 6 6

What is ‘Process capability’ ? Explain three possible relationships between process capability and specification limits of the dimension of the workpiece.

7

What do you understand by “Statistical control of production processes” ?

6

Number of defects (non – conformities) recorded for 10 lots containing different number of units are recorded below :

8

Lot 1 2 3 4 5 6 7 8 9 10

Unit 46 43 49 45 45 47 44 46 45 42

Non-Conformities 118 96 125 87 99 123 104 123 112 98

Construct appropriate control chart and comment about the process.

OR 10.

(a)

Sample of 5 were taken at regular intervals from a process. 10 samples in all being taken. The results were as follows :

Sample No 1 2 3 4 5 6 7 8 9 10

747 748 749 749 749 749 750 751 751 751

Measurement Per Sample (hundredths of one mm) 748 747 749 749 750 748 748 750 748 749 750 750 749 750 750 750 751 749 750 751 751 750 750 750 751 752 751 752 752 753

748 749 749 751 751 750 750 752 751 751

Construct X and R charts and interpret the charts. Given : For Sample Size 5, A2 = 0.577. D4 = 2.115, D3 = 0 (b) Compare attribute charts and variable charts, used in SQC. 11

(a) (b)

12.

(a) (b)

What is operating characteristic (o.c.) curve ? Discuss in detail the characteristics of o.c.curve. Explain multiple sampling planes. OR Discuss the interest of the consumer and the producer in the selection of sampling plans. Differentiate between single sampling plan and double sampling plan. ***

8 6 8 5 7 6

SNP – 906/TWA-5836 METROLOGY AND QUALITY CONTROL SECTION A 1.

(a) (b) (c)

State and explain the four grades of standards depending upon the importance of standard. What is meant by the term “flatness” as applied to metrology? Determine the tolerances on the hole and the shaft for a precision running fit designated by 50 H7g6. You may use the following aid for solving the problem or use IS 919 for convenience :(i) 50 mm lies between the range 30-50 mm. (ii)

2.

(a)

(b) 3.

(c) (a) (b) (c) (d)

4.

(a) (b)

i = 0.45

3

5 2

D + 0.001 D (microns) (iii) Fundamental deviation for g shaft g shaft = -2.5 Do-34 (iv) IT 6 = 10 i IT 7 = 16 i State the actual maximum and minimum sizes of the both hole and shaft and maximum and minimum clearances. 6 OR Calculate the following quantities :6 (i) Wavelengths of the orange radiations of krypton 86 in an inch. (ii) Position of the supports from the end of a bar of 800 mm, considering the minimum central deflection. (iii) Same as (ii) but considering Airy points. Give the detailed classification of plain gauges. Explain each briefly. 5 What are the necessary conditions for interference of light waves ? 2 Describe the essential characteristics of comparator. 3 Distinguish between Comparator and Gauges. 3 Show by means of a sketch; the design of a sine bar, and state without quoting values, the features of sine bar which have tolerances for accuracy. 4 Give the design principle i.e. Taylor’s principle of thread gauge design. 3 OR Describe with neat sketch the construction and working of a solex pneumatic comparator. 7 How the effective diameter of a screw thread is measured ? 6

5.

(a) (b)

6.

(a) (b) (c)

7.

(a)

(b) 8.

(a)

(b) 9.

(c) (a) (b) (c)

What are the different elements those required to check the accuracy of the Gear ? Explain the method of Lead and tooth thickness measurement. 7 Explain with the help of neat sketches principle and construction of an Autocollimator (i.e. Injected graticule autocollimator). 7 OR Explain the concept “Flatness”. How it is indicated ? 4 What are the reasons for controlling surface texture ? 3 Explain what is meant by the ‘lay’ of a machined surface, and with the simple diagrams show the direction of lay for each of the following operation : (i) Facing at a capstan lathe; (ii) Grinding a flat surface at a surface grinding machine, (iii) Milling a flat surface using an inserted tooth face milling cutter. 7 SECTION B Explain the following terms in respect of quality :(a) Product Feature (b) Customer (c) Grade (d) Need 6 “Attainment of quality requires the performance of a wide variety of identifial task and function.” Explain briefly. 8 OR Explain the following terms :(i) Cost of prevention (ii) Cost of appraisal (iii) Cost of failure 6 What do you mean by the word “Quality” in present day context ? What are the quality characteristics ? 5 Explain the objectives for ‘Break through’ and ‘Control’. 3 What features of statistics entrusted in statistical quality control ? 4 Explain with neat sketches the various patterns of control charts with their expectable causes. 4 Control charts for x and R are maintained on a certain dimension of a manufactured part, measured in inches. The subgroup size is 4. The values of x and R are computed for each subgroup. After 20 subgroups,

∑ x =41.340 and ∑ R = 0.320.

Compute the values of the 3 sigma limits for the x and R charts, and estimate the values of σ1 on the assumptions that the process is in statistical control. OR

5

10.

(a) (b) (c) Lot No. 1 2 3 4 5 6 7 8 9 10

11.

Number Rejected 5 10 12 8 6 5 6 3 3 5

Fraction Rejected 0-050 0-100 0-120 0-080 0-060 0-050 0-060 0-030 0-030 0-050

Lot No. 11 12 13 14 15 16 17 18 19 20

Number Rejected 4 7 8 2 3 4 5 8 6 10

6 2

Fraction Rejected 0-040 0-070 0-080 0-020 0-030 0-040 0-050 0-080 0-060 0-100

Total No. of Rejects = 120 Construct appropriate control charts and state whether the process is in control ? 5 (a) How might a company protect itself against being supplied with material of inferior quality ? Discuss the concept of ‘Consumer’s risk’ and ‘Producer’s risk’, in connection with acceptance sampling scheme. (i) State the objectives of acceptance sampling. (ii) What are the four types of acceptance control methods ? 7 (b)

12.

Explain the difference between Variable control charts and Attribute control charts. Why a ‘np’ chart is not recommended when the subgroup size is variable? In a factory producing spart plugs, the number rejected found in the inspection of 20 lots of 100 each is given :-

(a) (b)

Explain acceptance/rejection and acceptance/rectification plans. 6 OR Explain Single sampling, Double sampling, Multiple sampling and Sequential sampling plan. 10 Define AQL, LTPD, AOQL. 3 ***

NVD/1295 METROLOGY AND QUALITY CONTROL 1.

a) b)

2.

a) b)

c) 3.

a) b)

4.

a) b)

5

a) b)

6.

a) b)

SECTION A Define ‘metre’ as of today. What are advantages of optical standard over material standard ? Give classification of limit gauges and explain any two with the help of diagrams. OR Explain briefly the difference between the interchangeable manufacture and selective assembly. Why is it necessary to give a tolerance on an engineering dimension ? Give examples of :i) unilateral tolerance, ii) bilateral equal tolerance, iii) bilateral unequal tolerance, Discuss the salient features of line measuring and measuring instruments. Describe any of the optical comparators. Also comment on the magnification obtained in it. Explain the construction, working and uses of the universal bevel vernier protractor. OR With a neat diagram illustrate the principle of a dial indicator, show clearly the method adopted to obtain magnification of the plunger movement. Name the different elements required to be measured checked in order to determine the accuracy of screw threads. Also sketch and explain limit of screw threads. Also sketch and explain limit gauges for internal threads. Explain briefly how a precision level can be used to determine flatness and straightness of machine beds. Name and define the various elements of a spur gear which are checked for correct functioning of a gear. Explain the method for checking pitch of a spur gear. OR Explain the base tangent method of gear tooth thickness measurement. Discuss the adverse effects of poor surface finish. Also, explain the following terms related to surface texture measurement. (i) Lay (ii) Ra (iii) Sampling length.

6 9 5

4 5 7 6

7

6 6 7 5 8

7.

a) b)

8.

a) b)

9.

10.

11.

12.

SECTION B Explain the term “optimum quality of design” with help of a graph. What do you mean by the term “field complaints ? State the significance of field complaints in quality assurance function. OR What is “Quality mindness”? How does it help in improving the quality of the product ? What are the three main elements of quality function ? Explain.

6 7 7 6

Compare X chart with R chart. Discuss the circumstances in which either of the two or a combination of these will be used for the purpose of control. The following are the X and R values of 4 subgroups of readings :3+3+8 X = 10.2, 12.1, 10.8 and 10.9 R = 1.1, 1.3, 0.9 and 0.8 The specification limits for the components are 10.7±0.2. Establish the control limits for X and R charts. Will the product able to meet its specification ? Given : A2 ( factor for X chart ) = 0.58 D4 ( factor for R chart ) = 2.11 D5 ( factor for R chart ) = 0.00 OR a) Compare attribute charts and variable charts of quality control. 7 b) What is process capability ? The design specifications for a component are 100 ± 0.5 mm. Whereas the process report shows that process average is 99.9 mm and standard deviation is 0.18. Do these figures call for any action by any one ? What action is necessary and by whom ? 7 a) Compare random sampling and stratified sampling. 6 b) What is meant by O. C. curve ? Sketch neatly the ideal and actual O. C. curve. How O. C. curves are useful in selecting acceptance level ? 7 OR a) What do you mean by Acceptance sampling ? How does it help in Quality control ? 5 b) Explain Single sampling and Double Sampling plan. 8 ***

DVW/1193 Third Year B. E. (Prod.) Examination METROLOGY AND QUALITY CONTROL SECTION A 1.

a) b)

2.

a) b) c)

3.

a) b)

4.

5.

a) b) a) b)

6.

a) b)

What do you understand by Line and End measurement ? Discuss their relative characteristics. Determine the diamensions and tolerances of shaft and hole having size of 30 H7 h8. Also determine the allowances (i.e. minimum and maximum clearances ). Use may use : 1) 30 mm lies in 18-30 step, 2) i = 0.45 3 D + 0.001 D. 3) IT.7 = 161 and IT 8 = 25i. OR What is gauge maker tolerance and were tolerance ? How it is applied in gauge design ? What are the advantages and limitations of limit gauges ? Explain with neat sketches the basic hole system and unilateral system. A 200 mm size bar is to be set to an angle of 320 5’ 6”. Find the length of gauge blocks required from 87 piece set. Give the fundamental requirements which every comparator must fulfil. OR Give importance of front reflecting mirror in case of optical comparator. How magnification is achieved in optical comparator ? Explain ‘Principle of Vernier’ and use of Vernier height gauge. What do you mean by ‘Master Gear’? Give the different elements to be checked for accuracy of a gear. ( Spur Gear ). Explain in short any three. What are the components of surface Texture ? What is the reason for controlling surface texture ? Explain ‘Tomlinson’ surface meter. Enumerate the advanatages and limitations of dial indicator.6

6

8 4 3 7 6 7

6 7 7 6 7

SECTION B 7.

a) b)

The Quality cost is determined as internal failure cost and external failure cost. Explain. Attainment of quality requires the performance of wide variety of identifiable task and functions. Explain.

6 8

8.

a) b)

9.

a) b)

OR What do you understand by ‘Quality audit and how is it conducted in an industrial organization ? What do you mean by the word ‘Quality’ in present day context ? What are the Quality characteristics ? Why statistics comes to frey in quality control ? Data were collected for a large box of bolts containing about 10% non-confirming items. Plot ‘np’ chart based on the data given below.

Sub group No.

Number Inspected

1 2 3 4 5 6 7 8

200 200 200 200 200 200 200 200

Number Nonconforming 28 20 24 19 17 25 25 22

9. 10. 11. 12.

200 200 200 200

22 16 22 18

Sub group No.

Number Inspected

13 14 15 16 17 18 19 20 21 22 23 24 25

200 200 200 200 200 200 200 200 200 200 200 200 200

***

8 6 5 8

Number Nonconfirming 20 23 28 28 15 23 17 22 25 20 18 14 13

MNL-820/ALL-2772 METROLOGY AND QUALITY CONTROL SECTION-A 1.

2.

(a) (b) (a) (b)

3.

(a) (b)

4.

(a) (b)

5.

(a) (b)

6.

(a) (b)

Discuss the characteristics of line standards and end standards. What are limit gauges ? Sketch and explain any two types of limit gauges. OR State Taylor’s principle in design of limit gauges. What are the advantages of using progressive type gauge versus double ended plug gauge for checking holes ? Explain clearly the following types of fits :(i) Selective fit (ii) Driving fit (iii) Forced fit (iv) Shrinkage fit. What are possible errors in an external screw threads ? Sketch and explain limit gauges for external threads. Clearly distinguish between limit gauges and comparators. OR What are advantages of optical comparator over mechanical comparators ? Sketch and explain any one type of optical comparator. Which conditions must exist if a sine bar is to be accurate ? How sine bar is used for large components ? Define tooth thickness in case of a simple spur gear. How it is measured using vernier gear tooth caliper ? What is the expected accuracy of such a vernier ? Discuss the applications of Tool Maker’s microscope. OR Sketch and explain the working of Tomblinson surface meter. Define the term “Squareness” of a try-square. Describe in brief the reversal method used to test the squareness error of an engineer’s square.

6 8

8

6 8 5

7 6 7 6 7 6

SECTION-B 7.

(a) (b)

Define the term quality. Also differentiate between quality of design and quality of conformance. Explain the term “Quality Assurance Function”. What is “Quality mindness” ? How does it help in improving the quality of the product ?

6 7

8.

(a) (b)

9.

(a) (b)

OR What do you understand by Vendor Quality Rating ? Explain the need of V.Q.R. Explain the following as applied to the quality control :(i) Appraisal Cost (ii) Prevention Cost (iii) Failure Cost (iv) Optimum Cost. Distinguish between variable data and attribute data with appropriate examples. Following table refers to the average number of outlet leaks per radiator for 10 lots of 100 radiator each :-

Lot No. 1 2 3 4 5 6 7 8 Number of leaks 15 17 12 16 14 5 14 11 (c) Establish u chart for the future production. OR 10. What is “Process capability” ? Plot X and R charts if ∑ X = 357.50, ∑ R = 9.90, Number of subgroups = 20. 11.

12.

9

10

9

10

It is given that A2 = 0.18, D3 = 0.41, D4 = 1.59 and d2 = 3.735. Also find the process capability and comment on the process. (a) State the advantages and limitations of sampling inspection as compared to 100% inspection. (b) Explain single sampling plan and double sampling plan with respect to their respective acceptance criteria. OR (a) What is meant by O.C. curve ? Sketch neatly the ideal and actual O.C. curve. How O.C. curves are useful in selecting acceptance level ? (b) Discuss the interests of the consumer and the producer in the selection of sampling plans. ***

5

8 6

8

14 6 7

7 6

ICA/772 METROLOGY AND QUALITY CONTROL SECTION A 1.

2.

a) b) c) d) a) b)

3.

a) b) c)

4.

a) b) c)

5.

a) b)

Define present day meter in optical term. Clearly distinguish between Line Standard and End Standard. What do you understand by term Tolerance and allowance ?3 Give the advantages of using wave-length standard to define primary standard. OR What do you understand by limit gauges ? State Taylor’s principle for designing limit gauges. Design workshop type progressive type GO and NO GO plug gauge suitable for 20H7 You can use either IS 919 or the following information. i) 20 mm lies in diameter steps 18-30 mm, ii) Fundamental Tolerance unit in micron, i = 0.45 3 D + 0.001 D. What is comparator ? Give some design considerations for comparator. Explain the principle of optical comparator, give its advantages and disadvantages. State the essential requirements for accuracy in construction of sine bar. Why it is that the use of sin bar is not recommended for angles larger than 450 with the reference plane ? OR What is meant by drunken thread ? What difficulties does it present in finding the pitch of the thread ? Name the different elements required to be measure in order to determine the accuracy of screw thread. Give the methods of measuring the effective diameter of a screw thread. Explain the three wire method of ascertaining the effective diameter of a screw thread. Name and define the various elements of a spur gear which are checked for the correct functioning of a gear. Explain briefly each of the following terms showing its importance in measurement of surface texture. i) lay, ii) Ra, iii) Primary texture,

2 4 4 4

10 3 4

6 3 3 7 7

iv) Secondary texture.

6 OR

6.

a) b)

Explain the use of dial gauge and varnier height gauge. Describe with sketch the working principle and application of auto callimator.

6 7

SECTION B 7.

a) b) c)

8.

a) b) c)

9.

a) b) c)

10.

a) b) c)

11.

a) b)

What is the meaning of quality of conformance ? Explain factors which influence the quality of conformance. Define the term ‘quality control’ and explain its advantages over inspection technique. “Higher quality of design usually cost more and higher quality of conformance usually cost less”. Comment. OR How quality mindedness can be created in the organization ? What is quality assurance ? What are the steps involved in it ? “Inspection planning is a part of planning for quality”. Comment. Describe briefly the ‘Run Sum test’. What do you meant by process capability ? How will you determine the same ? A sub group of 5 items each are taken from a manufacturing process at a regular interval. A certain quality characteristics is measured and x and R values computed. After 25 sub-groups it is found that ∑ x = 357.50 and ∑ R = 8.80

4 4 6 4 5 4 3 6

If the specification limits are 14.4 ± 0.40 and if the process is in statistical control, what conclusion can you draw about the ability of the process to produce items within specification ? 5 OR What do you understand by “Statistical control of production process” ? 4 What are the advantages of use of statistical methods in quality control ? What is meant by natural tolerance of the process ? 3 State and explain advantages of limitations of acceptance sampling over 100% inspection. Explain the OC curve with reference to sampling inspection and the meaning of the terms – i) Producers Risk, ii) Consumer’s Risk

4

9

OR 12.

a) b)

c)

Differenciate between Acceptance/Rejection and Acceptance/Rectification schemes. Explain the following terms (any two) i) AQL, ii) AOQL, iii) LTPD. What are the advantages and disadvantages of double sampling plan ? ***

4

6 3

STD-1122/TMG-7628 METROLOGY AND QUALITY CONTROL SECTION A 1.

(a) (b) (c)

2.

(a) (b) (c)

3.

(a) (b) (c)

Enlist the advantages of wavelength standard. Define ‘Meter’ as of today. Explain with neat sketches various types of limit gauges and their applications. Define the following terms :(i) Limits (ii) Fits (iii) Tolerances (iv) Allowance. OR

3 7

Give the meaning of following specifications of limit gauges :(i) 30 H 7 (ii) 40 d 5. 4 Explain the concept of ‘Interchangeability’ and ‘Selective Assembly’. 5 What are the characteristics of line standards and end standards ? 5 How comparator differs from limit gauge ? Explain with a neat sketch the working of Pneumatic comparator. 5 A 100 mm sine bar is to be set at 220. Determine the slip gauges needed from 87 piece set. 4 Explain with neat sketch any two types of limit gauges for screw threads. 4 OR

4.

(a) (b) (c)

5.

(a) (b)

How mechanical magnification is obtained in plunger type dial indicator ? Give various applications of dial indicator with the help of sketches. Explain with a neat sketch the working of optical comparator.4 Enumerate various instruments used for angular measurements with their expected accuracies. What are the possible errors in a spur gear ? Explain the working of ‘Parkinson Gear tester’. Explain the basic working principle of autocolimeter.

6 3

7

Give its applications with the help of sketches. 6.

(a)

(b) (c)

OR In the measurement of surface roughness height of 20 successive peaks and troughs were measured from a datum and were 35, 25, 40, 22, 35, 18, 42, 25, 35, 22, 36, 18, 42, 22, 32, 21, 37, 18, 35, 20 microns. If measurements were obtained over a length of 20 mm. Determine the CLA and RMS values of the rough surface. Explain ‘Tool Maker’s microscope’. Give its uses and expected accuracy. How will you measure thickness of gear tooth using Vernier gear tooth caliper ?

6

4 5 4

SECTION B 7.

(a) (b) (d)

Define ‘Quality’. Discuss the factors controlling quality of design. 5 What is quality control ? State its objectives. 3 What is quality mindedness ? How does it help in improving quality of product ? 6 OR

8.

(a) (b)

9.

What do you mean by quality cost ? Describe various categories of quality costs. Discuss the steps involved in the quality control process.

7 7

(a)

Control charts for X and R are maintained on the tensile strength in N of a certain yarn. The subgroup size is 5. The values of X and R are computed for each subgroup. After 25 subgroups ∑ X 518.8, ∑ R = 120.

(i)

Compute the values of 30 limits for X and R charts. From table : A2 = 0.58 D2 = 0 D4 = 2.11. How will you decide whether the process is “in control” or “out of control” ? If a point representing certain subgroup in a control chart goes outside the control limits, what action should be taken ? 9

(ii) (iii) (b)

Being a ‘Quality control person’ how will you make choice between X, R, P and C charts ? OR

4

10.

The following are the results of daily inspection of a variance tube. Compute the value of fraction defective for each day inspection and plot the control chart. Find revised control limits and check these points and replot. Also comment on process capability :May 1996 3 5 6 7 12 13 14 17 18 24 25

11.

(a)

(b)

Lot size ‘n’ 1024 2056 16835 16069 7369 8738 1220 16242 15145 5845 13582

13

Number of defectives ‘φ’ 30 86 108 59 29 10 112 76 8 8 154

Define ‘Acceptance sampling’. Also distinguish between randon sampling and stratified sampling.

5

In a single sampling plan, n = 10 and C = 3, the lot size is large in comparison to the sample size. (i) Plot the O.C. curve for sampling plan. (ii) Find the probabilities of acceptance of lots 0.5% and 6% defectives.

8

OR 12.

(a) (b)

Discus the principles of acceptance sampling. Give complete analysis of Double sampling plan with suitable example. ***

5 8

PTV/869 AUTOMATIC CONTROL SECTION A 1.

(a) (b)

2.

(a)

(b)

3.

(a)

(b)

Obtain the transfer function of the mechanical system shown in fig.1. Obtain the transfer function y(s)/x (s) of the signal flow graph shown in fig.2.

6 7

A thermometer is dipped in a vessel continuing liquid at a temp of θI (t). The thermometer has a thermal capacitance for storing heat as C and a thermal resistance to limit heat flow as R. If the temperature indicated by the thermometer is θo(t), obtain the transfer function of the system.

6

Obtain the transfer function for the system shown in fig.3 by using block diagram reduction method.

7

What are pneumatic relays ? Explain bleed type and non – bleed type of pneumatic relays with the help of suitable diagrams.

8

Draw and explain the block diagram of automatic control system. 5 OR

4. 5.

(a) (a)

(b)

6.

(a)

(b)

Explain the working of hydraulic servomotor with the help of suitable diagram. Derive the transfer function for it.

7

The closed loop transfer function is given by. c( s) K = 2 R( s) s + a k s + k Determine the value of ‘K’ and ‘a’ so that the maximum overshoot in unit step response is 50% and the peak time is 5 seconds. Certain measurements were conducted on a servomechanism which show the system response as c (t) = 1 + 0.2 e- 60t – 12 e - 10t. when subjected to a unit step input. (i) Find the expression for closed-loop transfer function. (ii) Obtain the undamped natural frequency and damping ratio of the system. 7 OR Figure, 4 (a) shows a mechanical vibratory system. When 12 N of force is applied to the system, the mass oscillates as shown in fig. 4(b). Determine values of M, F and K for the system from response curve.

Explain the time domain specification with the help of suitable diagrams.

5

SECTION B 7.

(a) (b)

8.

(a) (b)

Explain the stability concept with reference to the control system. For the unity feedback system, K , plot the root locus. G(s) = s ( s + 2) ( s + 1) OR K (1 + s ) For a system G(s) H(s) , Find range of K S3 for system to be stable. Sketch the root locus of the unit feedback system with K ( s + 2) open loop transfer function G(s) ( s + 1) 2

5 7

5 8

7

9.

10.

11.

12.

(a)

What is frequency response ? Where is it applicable ? Discuss its advantages. 5 (b) What are the drawbacks of direct polar plots ? How are they overcomed ? Sketch the polar 10 plot for the transfer function G (s) = 8 s ( s + 1) OR Sketch the Bode plot for a unity feedback system characterized by the loop transfer function. 13 K (1 + 0.2 jw) (1 + 0.025 jw) G(s) = ( jw) 3 (1 + 0.001 jw)(1 + 0.005 jw) (a) Discuss the procedure of compensation using Bode plot. 5 (b) Derive the transfer function for electrical lag compensator and explain the effects of lag compensation. 8 OR (a) A unit feedback system has open loop transfer function. K Gf (s) = 2 s (1 + 0.2s ) Design a Load compensator to meet the following specifications. Acceleration error constant K2 = 10 phase margin = 350. 14 ***

NVD/1293 AUTOMATIC CONTROL SECTION A 1.

(a)

(b)

2.

(a)

(b)

3.

4.

5.

Why analogous system are important in control engineering ? Find an analogous mechanical system for an electrical system shown in fig.1, based on force voltage analogy.

7

Distinguish between following THREE types of system : (i) Linear and non linear (ii) Time variant and Time invariant OR Find out the transfer function for the control system shown in fig.2 using block diagram reduction method.

8

Find the gain x2/x1, for the signal flow graph shown in fig.3.

6

Explain how PID control can be obtained with the help of a pneumatic control action. Give its schematic diagram and derive its transfer function. OR (a) Explain the working of pneumatic proportional plus derivative controller with the help of a neat sketch and derive transfer function for it. (b) Enlist the basic control actions and explain any one of them. (a) (b)

Define steady state error and error constants of control systems. Deduce the error constant for type ‘0’ and type ‘1’ systems. Fig.4 shows a position control system with velocity feedback.

13

9 4 6

Find the time respose specification, when the system is subjected to unit step input. 7

6.

(a)

(b)

OR The open loop transfer function of a unity feedback system is, k G(s) = s ( s + 3) The specifications of a step input respose are as follows. Peak time = 0.8 sec. Percentage overshoot = 7% (i) Whether both specifications can be met simultaneously by a single value of K ? (ii) If not, determine the compromise value of K so that the specified values of peak time and percentage overshoot are relaxed by same percentage. 10 What do you understand by absolute stability, relative stability and steady state error ? 3 SECTION B

7.

8.

Open loop transfer function of a closed loop control system is given by K G(s) H(s) = ( s + 3) ( s + 5) ( s + 1) Draw root locus for this control system and also out value of K (i) Which will make system unstable. (ii) Which will make the system critically damped. 13 (a) Draw root locus of the control system having open loop transfer function 7 K ( s + 4) G(s) H(s) = S ( s + 2) (b) The characteristic equation of a control system is given by s4 + 6s3 + 11s2 + 6s + k = 0 what restrictions must be placed upon the parameter k

in order to insure that the system is stable ? 9.

Draw Bode plot for the control system having open loop transfer function s 20 ( s + 2) G(s) H(s) = s ( s + 1) ( s 2 − 8s + 64) also find out phase margin, gain margin, phase cross over frequency and gain cross over frequency.

6

14

OR 10.

11.

(a)

Differentiate polar plot and bode plot.

(b)

(c)

Obtain polar plot of the following transfer function. 5 gL e G(s) = 1 + sT Explain the terms resonance frequency and resonance peak. 4

(a)

Derive transfer function for electrical lead network.

(b) 12.

5

6

Explain the procedure for designing a lead compensator by root locus method. 7 OR The frequency transfer function of a second order control system is k G(jw) = jw ( jw + 1) Design a feedback control system which would satisfy the following frequency domain specifications phase margin greater than 400 K ≥ 12 sec-1 13 ***

3MP9/NUS/1276 THIRD YEAR B.E.EXAM. (Mech. Engg.) Automatic Control SECTION – A 1. a) b)

E0 ( s) for the electrical system shown in Fig.(a). 7 Ei ( s ) For the mechanical system shown in Fig. No.1(b). 6 write equation giving relation between : i) x and F ii) y and F iii) x and y Find the transfer function

OR 2. a)

b)

3.

Reduce the block diagram given in Fig. No.2 (a) to a canonical form retaining H2 in the feedback loop C (s) and final R (s)

C (s) for R (s) the system whose signal flow graph is given in Fig. No.2 (b).

6

Obtain the closed loop transfer function

7

Obtain the closed loop transfer function for the positional servo system considering that input and output shaft position θ as the input, and output shaft position θc as the output of the system respectively.(see fig.No.3). Draw the block diagram of the system.

7

4. 5. a)

b)

6. a)

b)

7. a)

b)

OR With the help of neat sketches, describe functioning of a pneumatic 7 PDI controller. Derive equation of its transfer function with error signal as input and controlled pressure as output. Draw its block diagram. Define the following specifications with respect to the transient response 5 the characteristics of a control system: i) delay time ii) rise time iii) peak time iv) maximum overshoot v) setting time. For the system shown in Fig.No.6 obtain rise time, peak time, maximum 9 overshoot and settling time, when the system is subjected to a unit step input, where µ = 0.6 and w = 5 red per second.

OR For the system shown in Fig. No.6 (a) determine the response to a unit step function, unit ramp function, and a unit parabolic function, when all initial conditions are zero. What is the steady state error to each of these inputs.

Obtain the unit step response of a unity feed back system whose open loop transfer function is : 4 G(s)= s (s + s) SECTION – B For each of the characteristic functions given below, determine the no. of zeros that lie on or to the right of the imaginary axis : i) s3 + 2s2 + 5s + 24 ii) s4 + 2s3 + 6s2 + 2s + 5 iii) s4 + 3s3 + 4s2 + 6s Find the range of gain ‘k’ for stability of a system having following characteristic equation : s4 + ks3 + s2 + ks + 1 = 0

8

6

6

7

OR 8.

Sketch the root loci for the closed loop control system with 13 system with K G(s)= s ( s + 1 ) + ( s 2 + 4 s + 5) H (s) = 1 9. a) Sketch the polar plot of the transfer function : 6 10 G(s)= s ( s +1) b) The specification given on a certain second order feedback control 6 system is that the overshoot of the step response should not exceed 25 %. a) What are the corresponding limiting values of the damping ratio ξ and peak resonance magnitude My? b) Determine the corresponding values for wp and Tmax 10 ( time to reach peak overshoot) when Wn = 10 rad per sec. 10. Sketch the Bode plot of the transfer function given by 200 ( s + 2) G(s) = s ( s 2 + 10 s + 100) give values of gain margin and phase margin obtained from the plot. E0 ( s) 11. a) Find the transfer function for the lag – lead compensator shown 7 E1 ( s) in Fig.No.11 (a).

b) With the help of a neat sketch describe a mechanical lag network and obtain its transfer function between output displacement and input displacement. OR 12. Consider the system shown in Fig. No.12. It is desired to design a compensator for the system, so that the static velocity error constant Kc = 20 sec.-1 the phase margin is atleast 500 and the gain margin is at least 10 ib. ***

7

14

3MP9 SNP/907 Third Year B. E. Exam. Automatic Control

1.

2.

3.

SECTION – A x2 (S ) a) Obtain transfer function of the mechanical system shown in fig.1. 10 F (S ) Also obtain analogous electrical circuit based on force voltage analogy.

b) Distinguish between time variant and time invariant control system. OR a) Obtain the closed loop transfer function C(S)/R(S) whose block diagram is shown in fig.2.

3

b) Obtain the transfer function C(S)/R(S) of signal flow graph shown in fig.3

6

a) Describe working of a bleed type pneumatic relay with the help of a neat schematic diagram compare it with non bleed type relay.

7

7

b) Draw a neat schematic diagram of pneumatic P1 controller and describe its working. OR

4.

5.

6.

a) Explain how one can obtain proportional plus derivative control action with a pneumatic amplifier. Draw its schematic diagram. b) What are basis control actions in any control system ? Explain PDI controller and desire its transfer function.

7

7 7

The open loop transfer function of a utility feedback system is given by K G(S)= 13 S (TS + 1) ii) By what factor should the amplifiers gain K be multiplied so that the damping ratio is increased from 0.25 to 0.75 iii) By what factor should K be multiplied so that the maximum overshoot of stop response is reduced from 80% to 20%. OR a) The open loop transfer function of a servo system with unity feedback is 10 G (S) = 13 S (0.1S + 1) Evaluate the static error constants and obtain the steady state error of the system when subjected to an input of A t2 r(t) = A0 + A1t + 2 2 b) Explain response specifications. 5

SECTION B 7.

9.

10.

11.

a) Use Routh’s stability criterion and determine stability of the following systems whose characteristics equations are i) ( S + 1 ) ( S + 2 ) ( S + 10 ) + 100 = 0 ii) ( S + 4 ) ( S + 6 ) + 125 = 0 6 c) Curtain negative unity feedback system has the forward path transfer function as given below 8 K ( S + 1) G (S) = S ( S − 3) Show that part of root lows is circular and plot the actual root locus. OR Sketch the root locus for the system having open loop poles at S = 0, -1, -2, -3 and no finite zeros from the root locus, obtain the value of gain for which system just stable. 14 Draw the Bode plot for the control system whose 13 20 H (S) = S (1 + 35) (1 + 4 S ) Determine phase and gain crossover frequency and phase & gain margin. a) Sketch the Polar plot of the following transfer function 6 1 G (S) = S ( S + 1)(2S + 1) b) What is closed loop frequency response ? Explain its significance. Also explain the persons out of frequency, band width and resonance peak. A unity feedback system has K G (S) = 2 S (1 + 0.25) Design a lead compensator to meet the following specifications Acceleration error constant Ka = 10 Phase margin = 350 OR

13

12.

For G (S) =

≥ 35 and Kv ≤ 20.13

K design a lag compensator, given pm S ( S + 2) ( S + 20) *** JKC-1150/GNU-2952 Faculty of Engineering & Technology Third Year B.E.(Mech./Prod.Engg.) (Annual Pattern) Examination AUTOMATIC CONTROL SECTION – A

1.

(a) A schematic diagram of a simple mechanical accelerometer for measuring the linear acceleration  d 2x   2  is shown in Fig. No.1. Determine the operational form for the  dt  differential equation, which relates ‘y’ (the change in position of the mass relative to the  d 2x  frame) to the acceleration of the frame  2 . 7  dt 

(b) In Fig.No.2 is shown an oven which is supplied with heat from an electric source. The rate of heat supplied is proportional to the voltage : (T − T1 ) . Qs = KEs. The rate at which heat is lost through the walls is Q = RT dT Qs − Q = . The rate of change of temperature of the oven is dt CT Construct the thermal circuit representation for this system, and determine the equation for temperature T of the oven as function of the applied voltage E and the surrounding temperature T1. 6

OR 2.

(a) Reduce the block diagram shown in Fig.No.3. and find its transfer C (s) function . R (s)

6

(b) Consider the system whose signal flow graph is shown in Fig. No.4. C (s) Obtain the closed loop transfer function by use of Mason’s gain R( s) formula. 7

3.

(a) State advantages and disadvantages of hydraulic control systems. (b) Describe how proportional plus derivative control action can be obtained in a hydraulic controller. Derive expression for its transfer function. Y ( s) . E ( s) Draw its block diagram.

5

9

4.

5.

6.

7.

8.

OR (a) Describe how can we reduce the sensitivity of a control system to parameter variations and unwanted disturbances by using feedback. (b) Describe working of a typical speed control system for a diesel engine, with the help of a neat sketch of the system. (a) Determine the time response y(t) for the transformed equation 11s + 28 Y (s) = . ( s + 2)( s + 5) (b) For the system shown in Fig. No.5 determine natural frequency, damping ratio, damped natural frequency, rise time, percentage overshoot and approximate 5% setting time.

6 8

6

7

OR (a) Determine the general equation for the transient response of a second order system to a unit step input change which occurs at t = 0, assuming all initial conditions as zero. The Laplace transform of the equation is wn2 R( s ) C(s) = 2 10 s + 2ξwn s + wn2 . (b) Explain the term logarithmic decrement. 3 SECTION-B (a) Applying Routh’s stability criterion to the following characteristic equation, find the condition for system’s stability a0s3 + a1s2 + a2s + a3 = 0. 6 (b) Considering the system shown in Fig. No.6, determine the range of K for stability. 7

OR Consider the system shown in Fig. No.7. Sketch the root loci of the system as the velocity feedback gain k varies from zero to infinity. Determine the value of k such that the closed-loop poles have the damping ratio ξ = 0.7.

13

9.

(a) Determine the resonant frequency wt, resonant peak Mr and bandwidth for the system whose transfer function is given by C ( s) 5 = 2 R( s) s + 2s + 5 1 (1 + s )(1 + 2 s). (b) Sketch the polar plot of the above transfer function, and determine the frequency at which the plot crosses the real axis and the corresponding magnitude G ( jw) . OR Sketch the Bode plot for the transfer function : 300 ( s 2 + 2 s + 4) G (s) = s ( s + 10)( s + 20) The open loop transfer function for a unity feedback system is 2 G (s) = s (1 + s ) (1 + 2s ). Sketch the bode plot for this system and : (a) determine the factor ‘Ke’ by which the gain should be changed so that the resulting system will have a phase margin of 450. (b) Determine the factor ‘KC’ by which the gain should be changed so that the resulting system will have gain margin of 5. OR A unity feedback system has open loop transfer function : K G (s) = 2 . s (1 + 0.2 s ) Design a lead compensator to meet the following specifications :Acceleration error constant Ka = 10 Phase margin = 350. *** G (s) =

10.

11.

12.

6

7

13

14

14

MOH-1097/DKF-11157 Third Year B.E.(Part II) (Prod.Engg.) 3P11:MACHINE TOOL DESIGN SECTION A 1.

2.

3.

4.

(a) How the bevel gears are classified ? Explain with neat sketches. (b) The layout of a double-ply leather belt drive is shown in Fig.No.1. The mass of the belt is 2 kg per metre length and the coefficient of Friction is 0.35. Calculate : (i) The tensions on the tight and loose sides and (ii) The length of the belt. The belt is transmitting 35 KW power.

OR (a) What are the applications of chain drive ? (c) A pair of parallel helical gears consists of a 20 teeth pinion and the velocity ratio is 3:1. The helix angle is 150 and the normal module is 5 mm. Calculate : (i) The pitch circle diameters of the pinion and the gear and (ii) The centre of distance. (a) A solid cast iron disk, 1.5 m in diameter and 0.23 m thick is used as a flywheel. It is rotating at 400 r.p.m. It is brought to rest in 2 seconds by means of a brake. Calculate : (i) The energy absorbed by the brake. (ii) The torque capacity of the brake. (The mass density of cast iron is 7200 kg/m3). (b) Enumerate the qualities of the friction material used in clutches. OR (a) Explain wedge film and squeeze film journal bearings. (b) What are the various types of brakes ? (c) Explain with suitable diagrams the methods for mounting the

6

8

4

10

9 4 5 3

5. 6.

7.

8.

9.

10.

11.

12.

rolling contact bearings. (a) Explain the trends in the design of machine tools. (b) What is the aim of speed and feed rate regulation ? Explain in detail. OR (a) Classify the feed boxes. (b) How the best possible structure diagram is selected ? SECTION B (a) A solid shaft is transmitting 1 MW at 240 r.p.m. Determine the diameter of the shaft if the maximum torque transmitted exceeds the mean torque by 20%. Take the maximum shear stress as 60 N/mm2. 10 (b) What are the various means for controlling the engagement of a clutch ? 4 OR A speed box having nmin = 20 rpm, nmax = 2000 rpm and φ = 1.26 is to be designed. Draw the best possible structural diagram and speed chart if the speed box has : (i) a structure with overlapping steps, and (ii) a structure with broken geometrical progression. (a) What are the functions of machine tool structures ? (b) What are the advantages of Anti-friction Guideways ? (d) Name the materials used for machine tool structures. On what factors the selection of material is depended ? OR Determine the outer and inner diameters of a hollow lathe spindle if their ratio = 2. The power on the spindle is 4.5 KW and it is rotating at 700 rpm. The peripheral and radial forces on the spindle are P2 = 215 kgf and T2 = 78 kgf. A horizontal force P1= 210 kgf and a vertical force T1 = 60 kgf are acting on the spindle nose. The spindle dimensions and loading are shown in Fig.No.2. (a) Explain the regulation of speed in electrical control circuits. (b) Discuss with neatly drawn sketches, the following tests :(i) Spindle centre run out and (ii) Chuck run out. OR (a) What is the advantage of Thermal Relay in machine tools ? (b) Name the various tests required to be performed for the accuracy of geometrical aspects of the job. Discuss any two of them in detail. -o-o-o-

5 7 6 7 6

14 5 4 4

13 7 6 6 7

SNP-910/TWA-5837 Third Year B.E.(Production Engg.) (A.P.) 3 P 11 : MACHINE TOOL DESIGN 1.

2.

3.

4.

SECTION A (a) Sketch the cross-section of V-belts and label its important parts. (b) What are the advantages and disadvantages of V -belt drive over a flat belt drive ? (c) A bronze spur pinion rotating at 600 rpm drives a cast iron spur gear at a transmission ratio of 4:1. The allowable static stresses for the bronze pinion and cast iron gear are 84 Mpa and 105 Mpa respectively. The pinion has 16 standard 200 full depth in volute teeth of module 8 mm. The face width of both the gears is 90 mm. Find the power that can be transmitted from the stand point of strength. OR (a) It is required to design a chain drive to connect a 10 KW, 1440 r.p.m. electric motor to a centrifugal pump running at 720 rpm. The service condition involves moderate shocks. (i) Select a proper roller chain and give a list of its dimensions. (ii) Determine the pitch circle diameter’s driving and driven sprocket. (b) What are the various types of belts ? On what factors the selection of a belt drive depends ? (c) Give the design consideration for gear drives and the requirements that must be met in the design of gear drive. (A) Explain the following terms as applied to journal bearings :(a) Bearing characteristics number (b) Bearing modulus. (B) Give and explain in detail the types of radial ball bearings. (C) A multiple disc clutch has five plates having four pairs of active friction surfaces. If the intensity of pressure is not to exceed 0.127 N/mm2, find the power transmitted at 500 rpm. The outer and inner radii of friction surfaces are 125 mm and 75 mm respectively. Assume uniform wear and take coefficient of friction 0.3. OR (A) The block brake, as shown in figure (1), provides the braking torque of 360 N-m. The diameter of the braking torque of 300 mm. The coefficient of friction is 0.3, find : (i) The force P to be applied at the end of the lever for the

3 4

7

4 7 4 3 4 4

5

clockwise and counter-clockwise rotation of the brake drum; and

(ii)

The location of the pivot or fulcrum to make the brake self locking for the clockwise rotation of the brake drum.

(B) What is meant by hydrodynamic lubrication ? Enumerate the factors, that influence most the formation and maintenance of the thick oil film in hydrodynamic bearings. 5.

6.

7.

8.

9.

(A) What do you mean by optimum ray diagram ? For what and how optimization can ensure in design of gear box. (B) What are the various laws of stepped regulations ? Why Geometric progression is commonly used in m/c tool drives ? OR (A) Give in detail the classification of speed boxes on basis of (i) General layout (ii) By method of changing speeds. (B) What are the features of stepless regulation of speed and feed rate ? (C) Give an account of fields of developments in machine tool engineering. SECTION B A speed box having nmin = 30 rpm, nmax = 1500 rpm and φ = 1.41. The number of speed step i.e. z = 12, which are to be realized in three stages i.e. u = 3. Motor rpm nm = 1440. [You may take n1 = 31.5, as it is closest rpm for φ = 1.41 of nmin = 30] Draw speed chart diagram and determine number of teeth of gears. OR (A) A 2x2 drive is required to be designed with speed ranging from 400 rpm with φ 1.41. Select a suitable structural form and optimum ray diagram. (B) What are the advantages of employing clutches to gear boxes ? What are the various types of clutch system in gear box ? (A) Give in detail the classification of guides used in machine tools. (B) What are the types of spindle supports ? What are the advantages and disadvantages of sleeve bearings ? (C) Why the protecting devices are used for slide ways ?

8

5 6 8

6 3 4

14

8 6 5 4

10.

11.

12.

Give their types by brief explanation. OR (A) What are the various methods used for compensating the errors in lead screws in machine tools. (B) What are the different forces taken into account while designing the machine tool structure ? (C) What do you mean by Hydrodynamic and Hydrostatic slide ways ? What are the distinguishing feature of Hydrostatic slide ways ? (A) Specify with diagrams how the following test would be carried out on a centre lathe :(i) The spindle axis parallel to the bed in both vertical and horizontal plane. (ii) Cross slide perpendicular to spindle axis. (B) Explain :(i) Ferromagnetic power clutch (ii) Thermal relay in machine tool. OR (A) Describe : (a) Geometrical test (b) Practical test (c) Acceptance test in machine tool. (B) What are the basic objectives of Acceptance test ? (C) Give the principle of use of electromagnet used in machine tool control and explain electromagnetic clutch. -o-o-o-

4 5 4 4 4

8 5

6 3 4

GBN/93 MACHINE TOOL DESIGN PAPER 3 P 11 SECTION A 1.

2.

3.

4.

5.

a) Distinguish between initial tension and centrifugal tension in the belt. b Give the principal advantages of worm and worm wheel drives, ) c) Give the advantages and disadvantages of chain drives compared with belt drives. d Discuss the applications of following types of gears :) (i) Spur Gear, (ii) Hedical Gear (iii) Bevel Gear, (iv) Worm Gear OR a) A Leather belt 9 mm x 250 mm is used to drive a pulley 90 cm in diameter at 336 rpm. If the active are on the smaller pulley is 120 0 and the stress in the tight side is 20 kg/cm2, find the Horse power capacity of the belt which weights 0.00098 kg/cm2, coefficient of friction of leather on pulley is 0.35. a) A friction clutch is to transmit 15 HP at 3000 rpm. It is to be of single plate type with both sides of the plate effective, the axial pressure being limited to 0.9 kg/cm2. If external diameter of the friction lining is 1.4 times the internal diameter, find the required diamensions of friction lining. Assume uniform wear conditions, the coefficient of friction is 0.3. b Write short note on lubrication in bearings with sliding contact, covering ) the following points :(i) Necessity, (ii) Condition for ideal lubrication, (iii) General properties of fluids used as lubricants. OR a) What are the basic design requirements of a clutch ? Enumerate various types of clutches b What do you mean by preloading of a bearing ? ) Give the methods of preloading of ball bearings. c) Explain air lubricated bearings. a) What do you understand by ‘machine tool drives’ ? What are its general requirements ? b Give the prominent features of using hydraulic drives for translatory

4 3 3

4

9

7

6 5 5 3 6

) 6.

7.

8.

9.

stepless regulations of feed and speed rate. What shortcomings are observed by using hydraulic drives ? 7 OR a) Give the prominent features of using stepless regulations of speeds which make their applications economically feasible. 5 b A 3x2 drive is required to be designed with speed ranging from 400 rpm ) with φ = 1.41, Select a suitable structural form and optimum ray diagram. 8 SECTION B Sketch the possible speed charts for nmin=16rpm n max = 770 rpm and = φ 1.26. If the motor runs at 1440 rpm and input shaft has a speed of 630 rpm select best speed chart and justify your choice. OR Design the feed box of a lathe machine for the feed range 0.05-4.0 mm/rev. Given φ = 1.41. Assume a suitable kinematic train between the spindle and the input shaft of the feed box and between the output shaft 14 of the feed box and rack. a) Give the types of Guideways and state the requirements that must be satisfied for its basic function. 5 b The lead screw of a lathe has Acme threads of 50 mm outside diameter ) and 10 mm pitch. It drives the tool carriage and excerts an axial pressure of 250 kg. A coller bearing with outside diameter 10 cm and inside diameter 5 cm is provided to take – up the thrust. If the lead screw rotates at 30 rpm; find the efficiency and horse power required to drive the screw. Take coefficient of friction for screw threads as 0.15 and for color as 0.12, 8

JKC-1153/GNU-2955 MACHINE TOOL DESIGN Paper : 3P11 1 .

SECTION A (a) Discuss the applications of helical gears and compare it with spur gear.

5

(b ) 2 .

3 .

Design a chain drive to transmit 12 kW from an electric motor running at 900 r.p.m. and having a transmission ratio of 2.80. The minimum centre distance is 500 mm. 9 OR (a) It is required to design a pair of spur gears with 200 full-depth involute teeth based on Lewi’s equation. The velocity factor is to be used to account for dynamic load. The pinion shaft is connected to a 10 kW, 1440 r.p.m. motor. The starting torque of the motor is 150% of the rated torque. The speed reduction is 4:1. The pinion as well as the gear are made of plain carbon steel 40C8(Sut = 600N/mm2). The factor of safety can be taken as 1.5. Design the gears and specify their dimensions. 9 (b What are the advantages and disadvantages of flat belt drive ? 5 ) (a) What are the different types of rolling contact bearings ? 7 (b )

4 .

A double-block brake consists of two symmetrical pivoted shoes. The diameter of the brake drum is 300 mm and the angle of wrap (20) for each shoe is 900. The pivot of the shoe is located in such a way as to avoid the couple due to frictional force. Determine the distance of pivot from the axis of the brake drum. 6 OR (a) The following data is given for a hydrostatic thrust bearing :Shaft speed = 720 r.p.m.; Shaft diameter = 400 mm; Recess diameter = 250 mm; Film thickness = 0.15 mm; Viscosity of lubricant = 30 cP; Specific gravity = 0.86; Specific heat = 1.75 kJ/kg0C; Supply pressure = 5 Mpa. Calculate (i) load carrying capacity of the hearing; (ii) flow requirement; (iii) pumping power loss;

(iv) frictional power loss; and (v) temperature rise. How clutch differs from brake ?

5 .

6 .

(b ) (a) Explain in detail the mechanical devices for stepless regulation of speed and feed rates. (b What information is obtained from the structured diagrams ? ) OR (a) Give in detail the classification of feed boxes. (b )

What are the various factors used for selecting the best structural diagram ?

10 3 7 6 7 6

SECTION B 7.

Design the feed box of a lathe machine for the feed range 0.05-4.0 mm/rev. Given φ = 1.41. Assume a suitable kinematic train between the spindle and the input shaft of the feed box, and between the output shaft 14 of the feed box and the rack, attached to the underside of the lathe bed. OR 8. (a) What are the various types of friction clutches ? Explain any one in detail. 7 (b What is ray-diagram ? Discuss its importance in machine tool. 7 ) 9. (a) What are the important design requirements of the spindle unit ? 6 (b What are the advantages and disadvantages of plastic slideways ? 7 ) OR 10 (a) Explain the commonly used shapes of slideways in machine tools. Why . cylindrical slideways are rarely used in machine tool beds ? 8 (b What are the requirements that the machine tool structures must satisfy ? 5 ) 11. (a) Draw and explain the electrical circuit diagram for starting the motor of a machine tool. 6 (b Name and justify the alignment tests to be performed on a shaper. 7 ) OR 12 (a) Explain the regulation of speed in electrical control circuits. 5 . (b Name the different alignment tests to be performed on drilling machine. ) Describe the method for determining the total deflection. 8 -0-0-0-

DVW-1194/STS-5100 MACHINE TOOL DESIGN Paper : 3 P 11 SECTION A 1.

2.

(a) What is the low of 'Belting'? Distinguish between 'Slip' and 'Creep' for belt. (b Give the advantages and disadvantages of chain drives compared with the ) belt and gear drives. (c) A pair of Spur Gear consists of 20 T pinion meshing with a 120 T gear, the module is 4 mm calculate : (1) The centre distance. (2) The pitch circle diameter of the pinion and the Gear. (3) The addendum and the Dedendum. (4) Gear Ratio. OR (a) A Leather belt required to transmit 12 h.p. from a pulley 120 cm in diameter running at 200 rpm. The angle embraced is 165 degrees and coefficient of friction between Leather belt and pulley is 0.3. If the safe working stress for Leather belt is 14 kgf/cm2, the weight of Leather is 1 gm/cm3 and thickness of belt is 10 mm, determine the width of the belt taking the centrifugal tension into account. (b Give the design considerations for a Gear drives and the requirements that ) must be met in the design of Gear drives. (c) Give the advantages of Worm Gear drives.

5 5

4

8 4 2

3.

4.

5.

6.

(a) A multidisc clutch has three discs on the driving shaft and two on the driven shaft. The outside diameter of the contact surfaces is 240 mm and inside diameter 120 mm. Assuming uniform wear and coefficient of friction 0.3, find maximum axial intensity of pressure between the discs for transmitting 25 KW at 1575 rpm. (b What do you mean by Hydrodynamic lubricated bearings ? Explain ) wedge film Journal bearing and squeeze film Journal bearing. OR (a) What do you mean by air-lubricated bearings ? Explain. (b Discuss various types of breaks. ) (c) Explain with suitable diagrams the method of mounting the rolling contact bearings. (a) Give an account of fields of developments in Machine Tool Engineering. (b Give the prominent features of using hydraulic drives for translatory ) stepless regulations of speed and feed rate. What shortcomings are observed by using hydraulic drives ? OR (a) Give the main features of using stepless drives in high speed machine tool. (b Explain Geometric progression and harmonic progressions for stepped ) regulation of speed; when n1=30 rpm, n3 = 375 rpm and speed steps = 12 for velocity V=20 m/min. Explain your inference for selection of a particular progression with their advantages.

7.

8.

9.

(a) (b ) (a) (b )

10 .

(a)

(b ) (c) 11. (a)

SECTION B A speed box having nmin = 20rpm and nmax =2000 rpm and φ = 1.26 is to be designed. Draw the best possible structural diagram and speed chart if the speed box has : a structure with overlapping steps. OR A 2 x 2 drive is required to be designed with speed ranging from 400 rpm with φ 1.41 select a suitable structural form and optimum ray diagram. What are the advantages of employing clutches to gear boxes ? What are the various types of clutch systems in Gear box. (List only) Why the protecting devices are used for slideways ? Give their types by brief explanation. Give the functions of spindle units with design requirement that must be satisfied for operational capabilities of machine tool. OR Discuss the various factors for choice between cast iron and steel for the structure of machine tool. Give the distinguishing feature of power screws, those used in in machine tool. Explain the design of sliding friction power Screw. List the characteristics that require for selection of motor for operation

7 6 4 4 5 6 7 3

10

14

8 6 6 7 4 3 6

movements of machine tool. Explain Ward-Leonard system of controlling speed of motor.

(b ) (c) Explain the objective and procedure of 'Acceptance Test' for machine tool.

2 5 6

12 .

OR (a) Give the principle of use of electromagnet used in machine tool control and explain electromagnetic Clutch. 7 (b List and explain the instruments required for acceptance test of machine ) tool. 6 -o-o-o-

PTV/872 MACHINE TOOL DESIGN SECTION - A 1.

2.

3.

a) b ) c)

Enlist the requirements that must be met in the design of Gear drive. State precisely the reasons for V-belt drive being preferred over flat belt drives. A pair of parallel helical gear consists of a 20 teeth pinion meshing with a 40 teeth gear. The helix angle is 250 and the normal pressure angle is 200. The normal module is 3 mm, calculate. 1) The transverse module. 2) The pitch circle diameter of the pinion and the gear. 3) The centre distance. OR a) Explain and derive expression for beam strength of a gear teeth. b Find the length of belt necessary to drive a pulley of 80 cm diameter ) running parallel at a distance of 12 meters from the driving pulley of diameter 480 cm. a) A Friction clutch is to transmit 15 h.p. at 3000 rpm. It is to b of single plate type with both sides of the plate effective, the axial pressure being limited to 0.9 kg/cm2. If external diameter of the friction lining is 1.4 times the internal diameter, find the required diamensions of friction lining.

3 4

2 3 2 7 7

4. 5.

6.

7.

8.

9.

10 .

11

Assume uniform wear conditions. The coefficient of friction may be taken as 0.3. b What are rolling contact bearings ? Discuss their advantages over Journal ) Bearings. OR a) Establish a formula for the frictional torque transmitted by cone clutch. b What are the different lubricants used for lubrication of bearing ? Give the ) properties those required as lubricant in case of bearing. a) What do you understand by machine tool drives ? What is its general requirements ? b Give the prominent features of using hydraulic drives for translatory ) stepless regulations of speed and feed rate. What short comings are observed by using hydraulic drives ? OR a) Give the advantages of using geometrical progression in machine tool derives. What major shortcommings are observed in using geometrical progression ? b Give the prominent features of using stepless regulations of speeds which ) make their applications economically feasible. SECTION - B Sketch the possible speed charts for nmin = 16 rpm nmax = 770 rpm and φ = 1.26. If the motor runs at 1440 rpm and input shaft has a speed of 630 rpm select best speed chart and justify your choice.

7 6 6 7 6 7

7 6

14

OR a) Design a four speed Gear box to give speed variation between. 100 to 300 rpm. The input shaft runs at 17 rpm. Assume spindle speeds are in G.P. and find also no.of teeth on each Gear. 10 b What is PIV ? Explain ? 4 ) a) Derive an expression of optimum l/h ratio for a solid rectangular structure of height h and width b of simple machine tool bed, as simply supported beam loaded by a concentrated force P acting at its centre. 6 b Give the types of Guide ways and state the requirements that must be ) satisfied for its basic function. 7 a) What are the practical considerations made in the design of spindle of machine tool ? 6 b The lead screw of a lathe has Acme threads of 50 mm outside diameter and ) 10 mm pitch. It drives the tool carriage and exerts an axial pressure of 250 kg. A collar bearing with outside diameter 10 cm and inside diameter 05 cm is provided to take up the thrust. If the lead screw rotates at 30 rpm, find the efficiency and horse power required to drive the screw. Take coefficient of friction for screw threads as 0.15 and for coller as 0.12. 7 a) What important characteristics are to be taken into considerations while selecting a suitable motor for the drive of a machine tool ? 7

b ) 12 .

State the need of "acceptance test" for machine tool. Classify and explain the "acceptance test". OR a) Explain the Word-Lenoard system of controlling the speed of the motor over a wide range. b Specify with the diagrams how following test would be carried out on ) centre lathe. i) The spindle Axis parallel to Bed, ii) Cross-slide perpendicular to spindle Axis.

6 7

6

-o-o-o-

NVD/1296 MACHINE TOOL DESIGN SECTION - A 1.

2.

a) What are the factors upon which the coefficient of friction between the belt and the pulley depends ? b Define (i) normal pitch, and (ii) axial pitch, relating to helical gears. ) c) It is required to design a chain drive to connect a 10 KW, 1440 r.p.m. electric motor to a centrifugal pump running at 720 r.p.m. The service conditions involve moderate shocks 1) Select a proper roller chain and list of its dimensions. 2) Determine the pitch circle diamension driving and driven sprockets OR a) Give the design considerations for a Gear and the requirements that must be metal design of gear drives. b What are the various types of belts ? On factors the selection of a belt ) drive depend. c) A pair of bevel gears consists of a 30 pinion meshing with a 48 teeth gear. They are mounted on shafts, which are interset right angles. The module at the large the teeth is 4 mm. Calculate. 1)

4 4

3.

4.

5.

6.

7.

8.

9.

2) Number of teeth and pitch circle each gear. a) An automotive plate clutch consists of pairs of connecting surfaces with an a friction lining. The torque transmiting of the clutch is 650 N M. The coefficient friction is 0.35 and the permissible interpre 0.5 Nimm2, due to space limit the circle diameter of the friction disk is as 250 mm., using the uniform wear calculate. i) The inner dia of the friction disk, ii) The spring force required to keep clutch in engaged position. b Explain with suitable diagrms the melt mounting the rolling contact ) bearings. c) What is meant by hydrodynamic lubrication. OR a) A solid cast iron disk, 1.5 m in diameter and 0.23 m thick is used as a flywheel. It is relating at 500 r.p.m. It is brought to rest in 1 seconds by means of a brake, calculate. 6 i) the energy absorbed by the brake, ii) the torque capacity of the brake. b Explain wedge film and squeeze film journal bearings. 5 ) c) What are the commonly used materials for sliding bearings ? 2 a) Give an account of fields of development in machine tool engineering, b Clarify drives and discuss the various factors to be ) considered in the selection of machine tool drives. 5 c) Give the main features of using stepless drives in high speed machine tool 2 OR a) How the best possible structure diagram is selected ? 4 b What is the sim of speed and feed rate regulation ? 5 ) c) Find the speed steps arranged in geometric and arithematic progressions 6 for the following conditions : ηmin = 300 , ηmax = 520 Z = 4 SECTION - B a) A four - stage, 16 - step. speed box with ηmin = 32 and φ = 1.21 is powered by a two - speed, ( 1500/750 ) ac motor. Draw i) the structural diagram and speed chart of the speed box. 14 ii) Gearing diagram showing number of teeth on gears. OR a) What are the rules to be followed for the layout of gearboxes with gilding clusters. 5 b What function does a friction clutch perform in transmission train ? 5 ) c) What are the different important mounting used for ball bearing ? Give their sketches. 6 a) What are the various factors affecting selection of material for machine tool structures ? 5 b Classify the protecting devices for slideways. 3 )

c) What are the considerations to be made for successful design of machine tool structure ? What are the function of machine tool structure ? OR 10 a) Classify the power screw used in machine tool in detail. Why the power . square threads preferred to acute and buttress threads ? b Name the various materials used for machine tool structures. ) c) What are the different shapes of slideways ? Explain with sketches. 11. a) Name the various alignment test to be performed on a lathe. Describe any one. b Explain the working of electrical brakes. ) c) What are the basic objectives of acceptance tests ? OR 12 a) Draw electrical circuit diagram for the starting and stopping of the motor . of a machine tool. b Explain the working principle of ferromagnetic powder clutch with neat ) sketch. c) Give the name of different test to be performed on the lathe spindle.

5 5 2 5 5 5 3 4 6 3

-o-o-o-

773 MACHINE TOOL DESIGN PAPER 3-PH SECTION A 1.

2.

a) What are the factors upon which the coefficient of friction between the belt and pulley depends. 3 b A pair of bevel gears consists of a 30 teeth pinion meching with 48 teeth ) gear. The gears are mounted on the shaft which are intergecting at right angle. The module at the large end of the tooth is 4mm. Calculate i) Pitch circle diameter of the pinion and gear. ii) The pitch angles for the pinion and gear. 10 OR a) What are the advantages of worm gear drives ?

b )

3.

4.

5.

A simple roller chain No. 10 B is used to drive the cam shaft of an internal combusion engine. Both shaft rotates at 350 rpm and the centre distance between their axis should be approximately 500 mm. The number of teeth on each sprocket wheel is 19. Calculate i) Number of chain links. ii) the correct centre distance. a) Explain the 'Braking System' in machine tool; with suitable electrical circuit. b Explain an 'Electro magnetic clutch' with neat sketch. ) OR a) What are antifriction bearings ? Compare them with sliding bearings and classify them. b What is hydrostatic bearings ? Classify them. Justify its use in a machine ) tool. a) Give general classification of machine tools. b Explain why geometrical progression is commonly used in machine tool ) drive for stepped regulation. Prove the relation which indicate minimum loss of speed in transmission by using G. P. series.

6 7

6 7 3 1 0

6.

7.

8.

9.

OR a) How the stepless regulation of speed in machine tool are classified ? 4 b Explain the various mechanical friction drives used in machine tools. ) Discuss their limitations, advantages and disadvantages. 9 SECTION B a) What is the basic characteristic difference between design of speed gear box and feed gear box. 5 b What is the initial, essential information which is required for designing a ) speed box ? 3 c) Classify the speed boxes. 2 d Compare sliding key type and mortion type of gear box. 4 ) OR Design the head stock gear box of turret lathe arrangement for nine spindle speeds ranging from 50 rpm to 1500 rpm. The rating of motor being 10 hp and minimum number of teeth on gear is 25i) Represent with structure diagram, ii) Select optimal say diagram, iii) Calculate the gear ratios, iv) Calculate the shaft size and sketch the lay out of gear box. 14 a) What is the function of a guide ways ? What are the main requirements that a guide way must satisfy. 6 b Justify use of plastic as a material for machine tool guide ways. What are ) the disadvantages of this material as used for guide ways ? 7 OR

10 .

a) Compare the stiffness of various profiles used for machine tool structures.

b ) 11. a) b ) 12 .

Discuss the factors affecting stifness of machine tool structures and methods of improving it. Explain the selection criterion of machine tool primemover. Explain the electrical drive used in planning machine.

OR a) How would you check the following on a radial drilling machine ? i) Squareness of column with base. ii) Parallalism of radial arm guide ways with the base. iii) Squareness of direction of feed with base, iv) Runout of spindle. b What is stick slip ? Explain its effects on machine tool performance ? ) Suggest remedies.

5 8 7 6

8 5

STD/1123 MACHINE TOOL DESIGN PAPER 3 P II SECTION A 1 .

2

a) Discuss the various types of belts and the material used for transmission of power. b Discuss the characteristics of general purpose and special purpose machine ) tools. OR a) Discuss how speeds feeds and power transmission requirement are chosen

6 7

.

3 .

4 .

5 .

6 .

7 .

for a proposed machine tool. b Design a four speed gear box to give speed variation between 100 to 300 ) rpm. The input shaft runs at 175 rpm. Assume spindle speeds are in GP and find also Nos. of teeth on each gear. a) Describe different types of bearings employed in machine tool.

6

b Compare ball and roller bearings. ) c) Explain the method of lubrication of journal bearings used for machine tool spindles. OR a) Discuss the types of clutches, brakes and speed charge devices employed on machine tools. b What are the important factors in brake design ? ) c) Why a positive clutch is used ? a) What are the main types of machine tool drives ? Discuss the desirable characteristics of an ideal drive. b Describe the different types mechanical stepped drive used in machine tools, ) with the help of neat sketch. c) Show by means of sketch some mechanical drives suitable for rectilinear motion. OR a) Explain the features of electrical stepped and stepless drives.

3

b What are the advantages of stepless drives ? ) Describe some commonly used mechanical steppless drives. c) Describe hydraulic drives for rotary and rectilinear motion. SECTION B a) How the range of spindle speed for a machine tool is selected ? b Discuss speed regulation in G. P. Series through saw diagram. ) c) Explain how constant loss of economic cutting speed takes place in G.P.Series. OR

8.

Design speed box for a turret lathe head stock having 9 (Nine) spindle speeds ranging from 30 rpm to 1000 rpm. i) Draw Structure diagrams. ii) Draw ray diagrams for feasible structure diagram and select the most suitable one. iii) Show the Layout of gear box and Connection to motor. Show number

7 4

6 7 4 2 5 5 4 4 6 4 6 4 4

of teeth on gears. It uses 6 HP - 1440 rpm motor. The minimum number of teeth on gear pinion is 18 and gear module is and find the blank dia of gears used. 14 9. a) What are the functions of machine tool structures ? Show types of cross 7 sections used for m/c tool beds and columns. b Explain in brief the basic design procedure for lathe bed design. Give 6 ) analysis of forces sustained by lathe bed during dynamic operation. OR 10 a) What is the importance of guide ways in machine tool design ? Describe the main types slide ways used in machine tools. 7 b From among the slide way combinations flat-flat, flat-V and V-V of the ) lathe; which one would provide for the least radial deflection ? 4 11. a) What are feed control devices ? Why are they needed ? Sketch important feed control devices. 6 b What is meant by machine tool testing ? Explain its importance. 7 ) OR 12 a) Discuss the chief types of geometrical and cutting tests carried out during . the acceptance testing of machine tools. 5 b What are machine tool test charts ? ) Prepare the test chart of ( any one ) i) Lathe machine ii) Drill machine iii) Milling machine -o-o-o-

ICA/910 OPERATION RESEARCH TECHNIQUE

SECTION A 1 .

a) O. R. is important to decision make-Comment.

2

b O. R. has unlimited scope of application comment. 2 ) c) Suggest the suitable model of O. R. and give reasons if any; for each of the O.R. problem :i) Fixing of production schedule for pipes of various sizes manufacturing concern. ii) Allocation of machining schedule for various machine in job work shop. iii) Preparation and launching of new product in the market. 6 d State whether the following statement are true or false and correct it if ) required. i) Model building is the exsence of the operation research. ii) L. P. model has two basic phases model formulation and model installation. 4