What Is L Ayo Ut Pla Nnin G

What Is L ayo ut Pla nnin g  Planning for the location of all machines, employees, workstations, customer service areas and flow patterns of materials and people around into and within buildings.  Layout planning is determining the best physical arrangement of resources within a facility  Facility resource arrangement can significantly affect productivity  Two broad categories of operations:  Intermittent processing systems – low volume of many different products  Continuous processing systems – high volume of a few standardized products

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Typ es of L ayo uts  Four basic layout types consisting of;  Process layouts - Group similar resources together  Product layouts - Designed to produce a specific product efficiently  Hybrid layouts - Combine aspects of both process and product layouts  Fixed-Position layouts - Product is too large to move; e.g. a building

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Pr ocess Layouts  Process layout unique characteristics include;  General purpose & flexible resources  Facilities are more labor intensive  Lower capital intensity & automation  Higher labor intensity

Pr ocess Layouts contin ued Here machines of similar type are arranged together at one place. Drilling dept, welding dept, heating dept, painting dept.

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Pr oduct L ayouts Machines are grouped in sequence and finished goods travel from machine to machine. In a paper mill, bamboos are fed into machine and paper comes from other end

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Hyb rid L ayo uts  Combine elements of both product & process layouts  Maintain some of the efficiencies of product layouts  Maintain some of the flexibility of process layouts

 Examples:  Group technology & manufacturing cells  In soap plant, manufacturing is arranged on product line principle but other services like heating, water treatment plant are arranged on functional basis.

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Fix ed-Po sit ion Layo ut  Used when product is large  Product is difficult or impossible to move, i.e. very large or fixed  All resources must be brought to the site  Scheduling of crews and resources is a challenge

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Designing product layout Step 1: Identify tasks & immediate predecessors Step 2: Determine the desired output rate Step 3: Calculate the cycle time Step 4: Compute the theoretical minimum number of workstations  Step 5: Assign tasks to workstations (balance the line)  Step 6: Compute efficiency, idle time & balance delay     

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Assembly line balancing Precedence diagram: circles=tasks, arrows show the required sequence. Determine cycle time:

Determine required workstations (theoretical minimum) Set rules for assigning tasks (number of following tasks, longest task time)

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1. Assign tasks to first workstation, using rules and staying within cycle time. Repeat for following workstations until all tasks are assigned. 2. Evaluate line efficiency: 3. Rebalance if efficiency is not satisfactory.

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Process Layout: Interdepartmental Flow Arrange departments consisting of like processes in a way that optimizes relative placement. Toy factory: shipping and receiving dept., plastic molding dept., stamping dept., metal forming dept., sewing dept., painting dept. Given   

The flow (number of moves) to and from all departments The cost of moving from one department to another The existing or planned physical layout of the plant

 Determine  The “best” locations for each department, where best means maximizing flow, which minimizing costs

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Process Layout: CRAFT Approach  It is a heuristic program; it uses a simple rule of thumb in making evaluations: 

"Compare two departments at a time and exchange them if it reduces the total cost of the layout."

 It does not guarantee an optimal solution

Process Layout: Systematic Layout Planning At times  Numerical flow of items between departments  

Can be impractical to obtain Does not account for the qualitative factors that may be crucial to the placement decision so SLP is used.

 Systematic Layout Planning 



Accounts for the importance of having each department located next to every other department Is also guided by trial and error 

Switching departments then checking the results of the “closeness” score

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Assembly Lines Balancing Concepts Question: Suppose you load work into the three work stations below such that each will take the corresponding number of minutes as shown. What is the cycle time of this line?

Station 1

Station 2

Station 3

Minutes 7 3 6 per Unit Answer: The cycle time of the line is always determined by the work station taking the longest time. In this problem, the cycle time of the line is 7 minutes. There is also going to be idle time at the other two work stations.

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Example of Line Balancing  You’ve just been assigned the job a setting up an electric fan assembly line with the following tasks: Task A B C D E F G H

Time (Mins) 2 1 3.25 1.2 0.5 1 1 1.4

Description Assemble frame Mount switch Assemble motor housing Mount motor housing in frame Attach blade Assemble and attach safety grill Attach cord Test

Predecessors None A None A, C D E B F, G

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Example of Line Balancing: Structuring the Precedence Diagram Task Predecessors A None B A C None D A, C A

Task Predecessors E D F E G B H E, G B

G H

C

D

E

F

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Example of Line Balancing: Precedence Diagram Question: Which process step defines the maximum rate of production? 2 1 1 1.4 A B G H C

D

E

F

3.25

1.2

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Answer: Task C is the cycle time of the line and therefore, the maximum rate of production.

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Question: Which process step defines the maximum rate of production? Production time per day 420 mins Max Production = = = 129 units Bottleneck time 3.25 mins / unit 2 1 1 1.4 A B G H Predecessors Task Time (Mins) Description A 2 Assemble frame None B 1 Mount switch A C 3.25 DAssemble motor E housing F C None D Mount motor A, C 3.25 1.2 1.2 .5 housing in1 frame E 0.5 Attach blade D Answer: Task the cycle timesafety of the F 1 C is Assemble and attach grillline and E therefore, the rate of production. G 1 maximum Attach cord B H 1.4 Test E, G

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Question: Which process step defines the maximum rate of production? Question: Suppose we want to assemble 100 fans per day. What would our cycle time have to be?

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A

1

B

1

1.4

G

H Answer: C 3.25

D

E

F

1.2

.5

1

Production time per period Required Cycle Time, C = Required output per period 420 mins / day C= = 4.2 mins / unit 100 units / day

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Example of Line Balancing: Determine Theoretical Minimum Number of Workstations Question: What is the theoretical minimum number of workstations for this problem? Answer:

Theoretical Min. Number of Workstations, N t Sum of task times (T) Nt = Cycle time (C)

11.35 mins / unit Nt = = 2.702, or 3 4.2 mins / unit

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Example of Line Balancing: Rules To Follow for Loading Workstations  Assign tasks to station 1, then 2, etc. in sequence. Keep assigning to a workstation ensuring that precedence is maintained and total work is less than or equal to the cycle time. Use the following rules to select tasks for assignment.

 Primary: Assign tasks in order of the largest number of following tasks

 Secondary (tie-breaking): Assign tasks in order of the longest operating time

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2 A

1 B

1 G

C

D

E

F

3.25

1.2

.5

1

Station 1

1.4 H

Task A C D B E F G H

Station 2

Followers 6 4 3 2 2 1 1 0

Time (Mins) 2 3.25 1.2 1 0.5 1 1 1.4

Station 3

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2 A

1 B

1 G

C

D

E

F

3.25

1.2

.5

1

Station 1 A (4.2-2=2.2)

1.4 H

Task A C D B E F G H

Station 2

Followers 6 4 3 2 2 1 1 0

Time (Mins) 2 3.25 1.2 1 0.5 1 1 1.4

Station 3

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2 A

1 B

1 G

C

D

E

F

3.25

1.2

.5

1

Station 1 A (4.2-2=2.2) B (2.2-1=1.2)

1.4 H

Task A C D B E F G H

Station 2

Followers 6 4 3 2 2 1 1 0

Time (Mins) 2 3.25 1.2 1 0.5 1 1 1.4

Station 3

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2 A

1 B

1 G

C

D

E

F

3.25

1.2

.5

1

Station 1 A (4.2-2=2.2) B (2.2-1=1.2) G (1.2-1= .2) Idle= .2

1.4 H

Task A C D B E F G H

Station 2

Followers 6 4 3 2 2 1 1 0

Time (Mins) 2 3.25 1.2 1 0.5 1 1 1.4

Station 3

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2 A

1 B

1 G

C

D

E

F

3.25

1.2

.5

1

Station 1 A (4.2-2=2.2) B (2.2-1=1.2) G (1.2-1= .2) Idle= .2

1.4 H

Task A C D B E F G H

Station 2 C (4.2-3.25)=.95

Followers 6 4 3 2 2 1 1 0

Time (Mins) 2 3.25 1.2 1 0.5 1 1 1.4

Station 3

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2 A

1 B

1 G

C

D

E

F

3.25

1.2

.5

1

Station 1

1.4 H

Task A C D B E F G H

Station 2

A (4.2-2=2.2) B (2.2-1=1.2) G (1.2-1= .2)

C (4.2-3.25)=.95

Idle= .2

Idle = .95

Followers 6 4 3 2 2 1 1 0

Time (Mins) 2 3.25 1.2 1 0.5 1 1 1.4

Station 3

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2 A

1 B

1 G

C

D

E

F

3.25

1.2

.5

1

Station 1

1.4 H

Task A C D B E F G H

Station 2

A (4.2-2=2.2) B (2.2-1=1.2) G (1.2-1= .2)

C (4.2-3.25)=.95

Idle= .2

Idle = .95

Followers 6 4 3 2 2 1 1 0

Time (Mins) 2 3.25 1.2 1 0.5 1 1 1.4

Station 3 D (4.2-1.2)=3

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2 A

1 B

1 G

C

D

E

F

3.25

1.2

.5

1

Station 1

1.4 H

Task A C D B E F G H

Station 2

A (4.2-2=2.2) B (2.2-1=1.2) G (1.2-1= .2)

C (4.2-3.25)=.95

Idle= .2

Idle = .95

Followers 6 4 3 2 2 1 1 0

Time (Mins) 2 3.25 1.2 1 0.5 1 1 1.4

Station 3 D (4.2-1.2)=3 E (3-.5)=2.5

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2 A

1 B

1 G

C

D

E

F

3.25

1.2

.5

1

Station 1

1.4 H

Task A C D B E F G H

Station 2

A (4.2-2=2.2) B (2.2-1=1.2) G (1.2-1= .2)

C (4.2-3.25)=.95

Idle= .2

Idle = .95

Followers 6 4 3 2 2 1 1 0

Time (Mins) 2 3.25 1.2 1 0.5 1 1 1.4

Station 3 D (4.2-1.2)=3 E (3-.5)=2.5 F (2.5-1)=1.5

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2 A

1 B

1 G

C

D

E

F

3.25

1.2

.5

1

Station 1

1.4 H

Task A C D B E F G H

Station 2

A (4.2-2=2.2) B (2.2-1=1.2) G (1.2-1= .2)

C (4.2-3.25)=.95

Idle= .2

Idle = .95

Followers 6 4 3 2 2 1 1 0

Time (Mins) 2 3.25 1.2 1 0.5 1 1 1.4

Station 3 D (4.2-1.2)=3 E (3-.5)=2.5 F (2.5-1)=1.5 H (1.5-1.4)=.1 Idle = .1

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Example of Line Balancing: Determine the Efficiency of the Assembly Line Sum of task times (T) Efficiency = Actual number of workstations (Na) x Cycle time (C)

11.35 mins / unit Efficiency = =.901 (3)(4.2mins / unit)

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Q1. An assembly line is to operate 8 hrs per day with desired output of 240 units per day. Given the task time and precedence relationships: Task Time Predecessor A 60 B 80 A C 20 A D 50 A E 90 B,C F 30 C,D G 30 E,F H 60 G

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Draw precedence diagram What is workstation cycle time? Balance this line using longest task time What is the efficiency of line balance

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B 80

E 90

A

C

60 20

F D 50

30

G

H

30

60

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

C = production time per day/required output per day = (8 hour/day)(3600 seconds/hour)/240 units per day = 120 seconds per unit



Efficiency =(T/Na*C) = 420/4*120= .875 or 87.5%

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Work station Task Task time Idle time 1 A 60 D 50 10 II B 80 C 20 20 III E 90 F 30 0 IV G 30 H 60 30

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Group Technology: Benefits 1. Better human relations 2. Improved operator expertise 3. Less in-process inventory and material handling 4. Faster production setup

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Group Technology: Transition from Process Layout 1. Grouping parts into families that follow a common sequence of steps 2. Identifying dominant flow patterns of parts families as a basis for location or relocation of processes 3. Physically grouping machines and processes into cells

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Fixed Position Layout Question: What are our primary considerations for a fixed position layout? Answer: Arranging materials and equipment concentrically around the production point in their order of use.

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Retail Service Layout  Goal--maximize net profit per square foot of floor space  Servicescapes   

Ambient Conditions Spatial Layout and Functionality Signs, Symbols, and Artifacts

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 Warehouse Layout Considerations:  Primary decision is where to locate each department relative to the dock  warehouse layouts; more docks, less storage space, and less order picking

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 Office Layout Considerations:  Almost half of workforce works in an office environment  Human interaction and communication are the primary factors in designing office layouts  Layouts need to account for physical environment and psychological needs of the organization  One key layout trade-off is between proximity and privacy  Open concept offices promote understanding & trust  Flexible layouts incorporating “office landscaping” help to solve the privacy issue in open office environments