Introduction To Work Study

INTRODUCTION TO WORK STUDY Rodger Koppa, P.E., Ph.D. Industrial and Systems Engineering

Work Study “The systematic examination of the methods of carrying on activities so as to improve the effective use of resources and to set up standards of performance for the activities carried out” (Ed) 1992

Introduction to Work Study (4th Ed) G. Kanawaty International Labour Office, Geneva, Switzerland

Work Study Approaches • Method Study – The What and How – Workplace design – Workplace layout

• Work Measurement/estimation – Time – Observation – Standards

Method Study: Tools • Process sequence charts • Process flow charting: – Worker(s) – Material – Equipment

• Process Time lining • Multiple Activity Chart

Process Chart Symbols = Operation (part, material, product modified or changed as result of operation = Inspection (verification of operation or quality control) = Temporary Storage/delay/in queue = Transport (material handling) = Storage (controlled or file)

First Things First • Make a list of steps to accomplish task • Classify steps according to basic 5 chart symbols: O, I, D, T, S • Sketch of assembly however crude can be valuable • Then chart the process: – Overview: Outline (Operations) Chart – Detail analysis: Flow Process Chart

Outline C har t Highest level of description Uses flowchart symbols O and I Each component of assembly has own column, symbols keyed to list of operations or events  Assembly proceeds in time from right to left  Time for each step can be estimated or left for later analysis   

Detail Flow Process Chart • Worker Type: Records what worker does • Material Type: Records how material is handled or treated • Equipment Type: Records how equipment is used • DFPC prepared for each major component (vertical line of Outline Process Chart)

Flow Diagram • For material handling and multiple work stations a Flow Diagram can be helpful • Use same symbols and numbers for events • Study flow charts and diagrams together to visualize the method

Process Critical Analysis 5 basic events classify into 2 major categories: 2. Something is actually happening to material or work piece (being worked on) 3. Material or work piece not being worked on—in transit, storage, or in queue

Being Worked on 3 things can be happening: 2. Make Ready activities: to prepare material/workpiece and set into position 3. Do operations: effects change in shape, chemical composition, physical condition 4. Put Away activities: material/workpiece move away after (2) Goal: Max (2); Min (1) and (3) Only (2) is “productive”

How to Max (2), Min (1;3) Consider: • Purpose • Place • Sequence • Person • Means For each activity recorded on the process chart

Remember? “I keep six honest serving men, They taught me all I knew; Their names are What and Why and When And How and Where and Who.” --Rudyard Kipling

Purpose • • • •

What is done? Why is it done? What else might be done? What should be done?

Goal: Eliminate unnecessary parts of the task

Place • • • •

Where is it done? Why is it done there? Where else could it be done? Where should it be done?

Goal: Combine or locate operations to simplify task

Sequence • • • •

When is it done? Why is it done just then? When could it be done? When should it be done?

Goal: rearrange sequence to be more effective and cut down time

Person • • • •

Who does it? Why does that person do it? Could anyone else do it? Who should do it?

Goal: Cut fatigue, combine jobs

Means • • • •

How is it done? Why is it done that way? How else might it be done? How should it be done?

Goal: Simplify!!

THUS Basic 5 Questions: • • • • •

What should be done? Where should it be done? When should it be done? Who should do it? How should it be done?

After Basic 5 Questions • Draw new process charts • Compare with original • Estimate times for each operation and compare original vs. improved/simplified • Ask Basic 5 again on each charted operation and see if further improvements possible • Sell to management ($, People, Schedule)

A Case Study Refer to Handouts Situation: Brewster Aviation Receiving/Inspection Dept Phase I: Receiving  Shipping cases unloaded from delivery trucks  Cases stacked one on top another  Cases unstacked and moved to receiving bench

Case Study (Cont’d) Phase II: Preliminary Inspection  Parts cartons removed from shipping case  Parts unpacked and checked against packing slip  Parts repacked in carton  Cartons replaced in shipping case  Case placed in queue for transport to inspection bench

Case Study (Cont’d) Phase III: Critical Inspection  Parts cartons removed from shipping case  Parts unpacked and inspected/measured with reference to specs  Parts repacked in carton  Cartons repacked in shipping case  Case transported to marking bench

Case Study (Cont’d) Phase IV: Marking and Inventory  Parts cartons removed from shipping case  Parts unpacked and marked for inventory  Parts repacked in carton  Cartons repacked in shipping case  Case transported to Stores  Cartons placed in bins in Stores until called for by Assembly

How Can This Material Flow Be Improved? Use Critical Question Approach: Just for openers-- Why must cases be stacked if then unstacked to open?  Why are reception, inspection, and marking places so far apart?  Why does the case have to go all around the building to reach Stores?  Why are cartons unpacked and repacked 3 times before reaching Stores?

Improved Method Highlights:  Shipping case goes right to a hand truck and is transported to unpacking place, opened, packing list removed, and taken to Receiving Bench  Cartons unpacked and parts placed on Receiving Bench  Parts counted against packing list, inspected, and inventoried  Parts repacked in cartons and cartons repacked in case  Case taken to Stores  Case stays on hand truck through all of above

Ask the RIGHT Questions What should be done?  Where should it be done?  When should it be done?  How should it be done? Get outside the BOX of “we’ve always done it this way!” 

Resource Much of the material in this lecture came from: Kanawaty, G. (Ed) Introduction to Work Study (4th Ed.) Geneva: International Labour Office 1992 Another resource: Groover. M.P. Work Systems and the Methods, Measurement and management of Work PearsonPrentice Hall 2007