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IE 419 Work Design: Productivity and Safety Dr. Andris Freivalds Class #2

IE 419 Work Design: Productivity and Safety Dr. Andris Freivalds Class #2. NEED FOR SAFETY – 5. Myths, misconceptions Safety doesn’t sell Catastrophic failures main concern Safety slows operations Safety is human (operator, user) problem Cheaper to pay insurance (McWane??)

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IE 419 Work Design: Productivity and Safety Dr. Andris Freivalds Class #2

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  1. IE 419 Work Design:Productivity and Safety Dr. Andris Freivalds Class #2 IE 419

  2. NEED FOR SAFETY – 5 • Myths, misconceptions • Safety doesn’t sell • Catastrophic failures main concern • Safety slows operations • Safety is human (operator, user) problem • Cheaper to pay insurance (McWane??) • Making product safer increases costs IE 419

  3. NEED FOR SAFETY – 5 cont’ COSTS AMOUNT OF SAFETY IE 419

  4. IE 419 – Work Design • Productivity • Productivity tools: PERT, Worker-machine charts, line balancing, plant layout • Work measurement: MTM-2, MOST, Work sampling • Safety • General safety principles: how torecognize & analyze problem, select & apply remedy • Quantitative analyses: JSA, fault-tree, cost-benefit • Legal aspects: Workers Comp, OSHA • Hazards: recognize & control specific hazards IE 419

  5. PRODUCTIVITY TOOLS Methods Study = Systematic recording of existing and proposed ways of doing work in order to improve productivity (to improve the job for the operator) • Select project • Get and present data • Analyze data • Develop ideal method IE 419

  6. Fig. 2.1 – Steps in Methods Study IE 419

  7. #1 – Select Project Pareto analysis • aka: 80-20 rule • 80% of problems from 20% of jobs • Focus on the 20% • Plot in descen-ding order as cumulative proba-bility distribution • DesignTools IE 419

  8. #1 – Select Project Gantt Chart • Horizontal bar chart of activities, shaded if done • A snapshot of the status of all activities • Focus efforts on those that are behind schedule IE 419

  9. METHODS STUDY (Next?) • Get and present data • Analyze data • Develop ideal method • All of these overlap • Use special charts • Quicker, efficient, for IEs • Focus on productivity improvement IE 419

  10. PERT and CPM (pp. 27-30) • PERT = Program Evaluation and Review Technique (1950s) • Booz Allen for U.S. government & military • Time has uncertainty • Minimizing time is main goal • CPM = Critical Path Method (1950s) • DuPont for large scale projects • Time is specified • Trade-off between cost and completion date IE 419

  11. BASICS • Set of well defined jobs (activities) • Totality of which defines a project • Jobs start/stop independently of each other • Jobs are ordered in specific (technological) sequence • Forms a graphical network diagram • Allows computational estimates IE 419

  12. GOALS/QUESTIONS • How long if every job works out ideally? (optimistic estimate) • How long if everything goes wrong? (pessimistic estimate) • With average conditions → likely result • How can project be shortened at least cost? (trade-offs) IE 419

  13. RULES/PROCEDURES #1 • List jobs and estimated duration time • Draw network diagram • Arcs or vectors to depict jobs • Arrows to indicate direction (progress) • Numbered nodes to indicate events • Events = start and end of jobs IE 419

  14. Job A Job B Job A Job C Dummy Job Job B Job D RULES/PROCEDURES #2 • No two jobs can be identified by same nodes 3 • 1 2 1 2 • Dummy jobs take no time, no resources • Only to show dependency 1 3 2 Job A Use Dummy Job Job B IE 419

  15. 4 1 2 3 5 4 1 2 3 5 C A D D E E B B C A RULES/PROCEDURES #3 • Show precedence relationships (IP) clearly • Jobs B & C both required for Job D • Job C not required for Job D (but needed further on) IE 419

  16. RULES/PROCEDURES #4 • Time = estimated duration of each job • Earliest start time (ES) = such that IP hold • Latest start time (LS) = without delaying project completion • Earliest finish (EF) = ES + time to complete job • Latest finish (LF) = LS + time complete job • Critical jobs = jobs which delayed, delay project • Float (slack) = difference between ES and LS; time that noncritical jobs can be ↑, without delaying project • Critical path = longest path of critical jobs, determines duration of project; zero float IE 419

  17. Ex #1- CRITICAL PATH (Travel Times) • Two PSU profs (Allen, Booz) drive to Washington DC for a meeting with their contract sponsor (U.S. Army) • Prof. Allen leaves State College at 8 AM • drives to Philadelphia (KP, 3 hrs) • get materials from subcontractor Lockheed Martin (0.5 hr) • then onto Washington DC (2.5 hrs) • Prof. Booz leaves State College 8 AM • drives to Pittsburgh (3 hrs) • meets 3rd prof (collaborator) for lunch (2 hrs) • then onto Washington DC (4.5 hrs) • What is earliest they can meet for dinner? IE 419

  18. 2 3 3 Booz 0.5 Allen 4.5 2.5 Ex. CRITICAL PATH - 2 IE 419

  19. Ex. CRITICAL PATH – 3Network Table IE 419

  20. Ex. CRITICAL PATH – 4Network Diagram 0.5 LM Ph 2.5 3 SC DC 3 4.5 Pi Lu 2 Critical Path = 3 + 2 + 4.5 = 9.5 Earliest dinner: 8 + 9.5 = 5:30 PM IE 419

  21. Ex. CRITICAL PATH - 5 • Critical path = 9.5 hours • Earliest dinner is 5:30 PM • Allen can leave 3.5 hrs later (11:30 AM) • Or drive more slowly, sightsee • Flexibility or slack in time = float • Practically: If Booz shortens lunch to 1 hr, then could meet a 4:30 PM IE 419

  22. Ex #2 – CPM and FLOAT (Building a House) 7 major steps in building a house (months): • A - Design & obtain financing (3) • B - Lay foundation (2) • C - Order materials (1) • D – Build house (3) • E – Select paint (1) • F – Select carpet (1) • G – Finish work (1) IE 419

  23. Ex #2 – CPM and FLOAT - 2 3 B 2 A 3 D 3 G 1 6 4 7 2 1 C 1 F 1 E 1 5 IE 419

  24. 3 B 2 A 3 D 3 G 1 6 4 7 2 1 C 1 F 1 E 1 5 Critical Path = IE 419

  25. 3 B 2 A 3 D 3 G 1 6 4 7 2 1 C 1 F 1 E 1 5 Forward Pass ES = max (EFi) EF = ES + t IE 419

  26. 3 B 2 A 3 D 3 G 1 6 4 7 2 1 C 1 F 1 E 1 5 Backward Pass LF = min (LSi) LS = LF - t IE 419

  27. 3,53,5 3 5,55,5 B 2 8,9 8,9 5,85,8 A 3 D 3 G 1 6 4 7 2 1 C 1 0,30,3 3,44,5 F 1 6,77,8 E 1 5 5,66,7 Float = LS – ES = LF – EF IE 419 Critical path = all with 0 float =

  28. 3 B 2 A 3 D 3 G 1 6 4 7 2 1 C 1 F 1 E 1 5 Crashing – Expediting job, reallocation of resources to shorten project duration IE 419

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