英文版IE知识培训

1、2002/9/26SMT Training for Productivity1Industrial Engineering :Work DesignPrepared by Ken Leung2002/9/26SMT Training for Productivity2Work DesignnMethods ImprovementnErgonomicsnAssembly line balancingnPrinciples of motion economynVarious type of chartsnWork measurementnTime studynActivity sampling20

2、02/9/26SMT Training for Productivity3Ergonomics nDefinitionnApply information about human behavior, abilities, limitations, and other characteristics to the design of tools, machines, system, tasks, jobs, and environments for productive, safe, comfortable, and effective human use. 2002/9/26SMT Train

3、ing for Productivity4Objectives nTo enhance the work effectiveness and efficiency.nIncreased convenience of use nReduced errors nIncreased productivity nTo enhance human values.nImproved safetynReduced fatigue and stressnIncreased comfortnGreater user acceptancenIncreased job satisfaction nImproved

4、quality of life2002/9/26SMT Training for Productivity5Twelve Principles of Ergonomics1. Work in neutral postures-eg. Wrist rests for keyboard and mouse.2. Reduce excessive forces-eg. Boxes with handholds for carrying.2002/9/26SMT Training for Productivity6Ergonomics Principles3. Keep everything in e

5、asy reach-eg. Keep materials within the “reach envelope” of the arm.2002/9/26SMT Training for Productivity7Ergonomics Principles4. Work at proper heights-eg. Heavy work should be performed lower than elbow height; precision work should be higher. 2002/9/26SMT Training for Productivity8Ergonomics Pri

6、nciples5. Reduce excessive motions -eg. Use power screwdriver.6. Minimize static load -eg. Use a pencil grip.2002/9/26SMT Training for Productivity9Ergonomics Principles7. Minimize pressure points -eg. Provide padding for hand grips.8. Provide clearance-eg. Provide visual access (carton delivery).20

7、02/9/26SMT Training for Productivity10Ergonomics Principles9. Move, exercise, and stretch -eg. Change adjustments of the chair for those sit for a long time.10. Maintain a comfortable environment -eg. Consider the quantity and quality of light at the workstation.2002/9/26SMT Training for Productivit

8、y11Ergonomics Principles11. Make displays and controls understandable -eg. Clicking is easier than memorizing commands.12. Reduce stress -eg. Design task to fit people.2002/9/26SMT Training for Productivity12Anthropometry nDefinitionnMeasurement of the human body and its biomechanical characteristic

9、s.nBiomechanical refers to the mechanical (machine-like) capabilities of the human skeleton-muscular systems.nMeasures our sizes and how we move and move easily.nNeed of AnthropometrynWe are not in the same size.nPoor design for mechanical abilities of the human body can lead to discomfort or injury

10、.nEg. Height of keyboard for a computer.2002/9/26SMT Training for Productivity13Anthropometric DatanStatic measures are used to determine size and spacing requirements of work space, eg., height, weight, seat to elbow height, and wing span.nDynamic measures are used to match the dynamic characterist

11、ics of controls to user, eg., range of motion for various joints, and strength of fingers.2002/9/26SMT Training for Productivity14Anthropometric DatanThe anthropometric data is performed in normal distribution.n50th percentile is the most of the population.n5th and 95th percentiles are the extremes.

12、2002/9/26SMT Training for Productivity15How to use anthropometric datanDesign for extremesnA standard is to design to fit 5th or 95th percentiles of the population.nDesign for most of the populationn50th percentile of the population should be used.nMake the design adjustable nThe design can fit 5th

13、to 95th percentiles of the population.2002/9/26SMT Training for Productivity16Examples Design aimsDesign examples: Examples of measurements to consider:Users that the design should accommodate:Easy reach Shelving Arm length, shoulder heightSmallest user:5th percentileAdequate clearance to avoid unwa

14、nted contact or trapping Cinema seats Shoulder or hip width, thigh lengthLargest user: 95th percentileA comfortable and safe posture Worksurface heights Elbow height, sitting eye height, elbow height (sitting or standing)Most of the users:50th percentileSpecial fitting Headphones Head circumferenceM

15、aximum range:5th to 95th percentile (adjustable design)2002/9/26SMT Training for Productivity17Assembly Line BalancingnEqualize workload among the assemblies.nIdentify the bottleneck operation.nEstablish the speed of the assembly line.nDetermine the number of work stations.nDetermine the labor cost

16、of assembly.nEstablish the percent workload of each operator.nAssist in plant layout.nReduce production cost.2002/9/26SMT Training for Productivity18Table for Assembly Line BalancingNo.Operation R-ValueCycle time# stationsAvg. cycle time% LoadHrs / 1000Pcs. / hrA1Sub-assembly 0.2160.2110.211003.5285

17、A2Assembly 0.2160.44130.1477010.595 Major items: operation description, R-value, cycle time, number of stations, average cycle time, percent load, hours per 1000 pieces, and number of pieces per hour. An example is as follows.12345672002/9/26SMT Training for Productivity19Items for Assembly Line Bal

18、ancing TableR-value (plant rate): -Takt time or time needed to produce a product.-= effective production time / required production volume.Cycle time:-Standard time for operation.-Collected from time study.# stations:-= Cycle time / R-valueAverage cycle time:-= Cycle time / # stations 12342002/9/26S

19、MT Training for Productivity20Items for Assembly Line Balancing Table% Load: -Tell how busy each work station is compared to the busiest work station.-% Load = Avg. cycle time / highest avg. cycle time.-Highest avg. cycle time (100% station) is the bottleneck.-100% station is reduced by 1%, then we

20、will save 1% for all stations.-The less percent loaded, the more desirable to be sub-assembled or combined.52002/9/26SMT Training for Productivity21Items for Assembly Line Balancing TableHours / 1000 : -The hours per 1000 units produced.-Choose the bottleneck station.-= (Avg. cycle time / 60 mins) x

21、 1000 -For more than one workers at the station, “hrs/1000” = # workers x “hrs/1000” of bottleneck.-Because everyone on an assembly line must work at the same rate.Pcs. / hr :-Number of units produced hourly by one worker at the station.-= 1 / “Hrs/1000” X 1000672002/9/26SMT Training for Productivit

22、y22Improve Assembly Line BalancingnCalculate the Line Balance ratenReducing the bottleneck station.nCombining the bottleneck station with an operation in front or behind.nCombining other operations to eliminate one of them.2002/9/26SMT Training for Productivity23Example: Original Line BalanceNo.Oper

23、ation R-Value(mins)Cycle time(mins)# stationsAvg. cycle time (mins)% LoadHrs / 1000Pcs. / hr1Place bottom housing on line and lubricate0.250.20010.200804.172402Assemble parts 3, 4, & 50.250.25010.2501004.172403Assemble parts 6 & 7 together and place sub-assembly in housing0.250.30520.153618.341204Dr

24、ive 6 bolts holding sub-assembly in bottom housing0.250.60030.2008012.50805Get vent cover & cement in place assembly to bottom housing0.250.19810.198794.172406Get top housing, apply cement & assemble to bottom housing0.250.29020.145588.341207Place in carton & in master carton (6 per) and aside to pa

25、llet0.250.62530.2088312.5080Total 131.354n Producing new plastic charger; 1200 units per 8-hrs shift (with 300 mins effective). 2002/9/26SMT Training for Productivity24Example: Original Line BalancenOriginal line balance rate= total cycle time / highest cycle time station x no. of stations= 1.354 /

26、(0.25 x 7) = 77.4%nPcs./hr = 60 / 0.25 = 240nImprove the bottleneck station by combining with an operation in front or behind.nCombine and eliminate work steps.nRe-design the jig & fixture.OperationsBottleneck or 100% load station2002/9/26SMT Training for Productivity25Example: Improved Line Balance

27、No.Operation R-Value(mins)Cycle time(mins)# stationsAvg. cycle time (mins)% LoadHrs / 1000Pcs. / hr1 & 2Place bottom housing on line, lubricate, & assemble parts 3, 4, & 5.0.250.45020.225987.631313 & 4Assemble parts 6 & 7 together. Place in housing & drive 6 bolts holding sub-assembly to housing.0.2

28、50.90540.2269915.26655Get vent cover & cement in place in bottom housing.0.250.19810.198863.822626 & 7Get top housing, apply cement & assemble to bottom housing, pack out.0.250.91540.22910015.2665Total 110.878n Improved line balance 2002/9/26SMT Training for Productivity26Example: Improved Line Bala

29、ncenImproved line balance rate= total cycle time / highest cycle time station x no. of stations= 0.878 / (0.229 x 4) = 95.9%nPcs/hr = 60 / 0.229 = 262nIncrease in output with decrease in no. of workstations. OperationsBottleneck or 100% load station2002/9/26SMT Training for Productivity27Principles

30、of Motion EconomynGuidelines for efficient and effective work station design.nSummarized to 4 major elements:nElimination nCombination nRearrangementnSimplification2002/9/26SMT Training for Productivity28Elimination nEliminate all possible jobs, steps, or motions.nEliminate irregularities in job.nEl

31、iminate the use of hand as holding device.nEliminate abnormal motions.nEliminate the use of muscles to maintain a fixed position.nEliminate muscular force by using power tools.nEliminate danger.nEliminate idle time.2002/9/26SMT Training for Productivity29Combination nReplace with one continuous shor

32、t motion.nCombine tools, controls, and motions.RearrangementnDistribute the work evenly between two hands.nShift work from the hands to the eyes.nArrange for a straight forward order of work.2002/9/26SMT Training for Productivity30Simplification nReduce eye travel.nKeep work in the normal work area.

33、nShorten motions.nAdapt handles, levers, pedals, buttons, etc., to human dimensions and musculatures.2002/9/26SMT Training for Productivity31Applying the Principles of Motion Economy1. Move both arms in unison or move them symmetrically, but do not move just one arm at a time.Eg. Take the cap off an

34、 ink bottle.2002/9/26SMT Training for Productivity32Applying the Principles of Motion Economy2. To minimize body movement by limiting movements to body parts with low time rankings.The following illustration shows the correlation between arm movement and working time.2002/9/26SMT Training for Produc

35、tivity33Applying the Principles of Motion Economy3. Minimize fatigue by repeating motions with a natural feeling of rhythm and by making your curved movements as smooth as possible.Do as little holding or adjusting of materials as you can.Use stands or jigs to hold your materials or tools for you.20

36、02/9/26SMT Training for Productivity34Applying the Principles of Motion Economy4. Keep materials and tools in specified places in front of and around you.5. Try to keep from fighting gravity with the materials you are handling; move them down, not up.Eg. Use a chute to transport the products by its

37、own gravity.2002/9/26SMT Training for Productivity35Applying the Principles of Motion Economy6. Try to set your chair or desk at the most comfortable position and make sure your lighting is bright enough and at a good angle.7. If you utilize your legs and feet, you can lighten the load on your arms

38、and hands.2002/9/26SMT Training for Productivity36Applying the Principles of Motion Economy8. Side-to-side eye movements are less tiring than up-and-down ones.9. Whenever possible, combine procedures, using your tools as extensions of your hands and feet. Try to combine two or more tools into one.20

39、02/9/26SMT Training for Productivity37Various types of chartsnUsed as record techniquesnOutline process charts:nOverview of a process with graphical representation.nShow principal operations () and inspections ().nAssist in the plant layout design, design of product, or machinery processes.2002/9/26

40、SMT Training for Productivity38Various types of chartsnFlow process chart:nActivities of men, material or equipment.nTwo or more subjects can be presented alongside each other to show their interdependence.nActivities are divided by 5 functions, operation (), transport (), storage (), delay (D), ins

41、pection ().nOnly the activities of particular subject, either man, material, or equipment, are recorded on a single chart.2002/9/26SMT Training for Productivity39nExample,Flow process chart:Inspecting and markingincoming parts(original method) 2002/9/26SMT Training for Productivity40nExample,Flow pr

42、ocess chart:Inspecting and markingincoming parts(improved method) 2002/9/26SMT Training for Productivity41Various types of chartsnTow-handed process chart:nUseful in showing idle time by either hand.nActivities of a workers two hands. nSimultaneous movements by both hands appear opposite each other.

43、nDescription of the activities represented by the symbols should be inserted.2002/9/26SMT Training for Productivity42nExample,Two-handed process chart:Cutting glass tubes(original method) 2002/9/26SMT Training for Productivity43nExample,Two-handed process chart:Cutting glass tubes(improved method) 2

44、002/9/26SMT Training for Productivity44Various types of chartsnMultiple activity charts:nConsider on the activities of a subject in relation to one or more others.nShow up clearly ineffective time within the process.nUseful in finding the best sequence of carrying out the various parts of the work.n

45、Operation / machine chart shows the interrelationship of the operator and the machine.2002/9/26SMT Training for Productivity45nExample,Multiple activity chart worker and machine:Finish mill casting (original method) 2002/9/26SMT Training for Productivity46nExample,Multiple activity chart worker and

46、machine:Finish mill casting (improved method) 2002/9/26SMT Training for Productivity47Time StudynMost common technique for setting time standards.nUseful for repetitive work.nProvide standard rate of working.nA means of assessing the amount of rest that should be associated with the job.2002/9/26SMT

47、 Training for Productivity48Time Study: Procedures1. Select the job to study.2. Collect information about the job.3. Divide the job into elements.4. Do the actual time study.5. Extend the time study.6. Determine the number of cycles to be timed.7. Rate, level, and normalize the operators performance

48、.8. Apply allowances.9. Check logic.10. Publish the time standard.2002/9/26SMT Training for Productivity49Time Study: Focus PointsnExtend the time studynCalculate average observed time.nDetermine performance rating.nCalculate normal time:- Normal Time = average observed time x performance rating nFi

49、nd out frequency (how many times a task is performed within a time period).nCalculate unit normal time. 2002/9/26SMT Training for Productivity50Time Study: Focus PointsnDetermine the number of cyclesnN = number of cycles nR = range of the sample of observations (in minutes)nA = required precision (+

50、/- 5% or 10%) nd2 = statistical constant (3.078 for 95% confidence level) nx = average time (in minutes)2002/9/26SMT Training for Productivity51Time Study: Focus PointsnPerformance ratingnRating is the process of adjusting the time taken by an individual operator to what could be expected from a nor

51、mal operator.nFour major factors: skill, consistency, working conditions, and effort.nEffort is the most important.nEffort is the operators speed, and is measured based on the normal operator working at 100%.2002/9/26SMT Training for Productivity52Time Study: Focus PointsnRelaxation allowancenIt is

52、the allowance for the periodic stops for personal needs or fatigue.nExample: going to washroom; getting a drink.nContingency allowancenIt is a small allowance of time which may be included in a standard time to meet expected items of delays.nOccurs infrequently or irregularly.nExample: interruptions

53、 by supervisors; changing materials.2002/9/26SMT Training for Productivity53Time study: ExampleStation No.OperationDescriptionFindings (sec)Required # cyclesAverage Time (sec)12345678910M15PWB 分割 & 蓋印12312913814011911611210212113216122.25102127131125121118M1626 pin, 電容, 振盪器, 接地線焊接48.6551.1448.6950.8

54、146.5049.1650.0048.2843.7852.061048.91M17電感焊接18.5919.0120.4020.1019.7518.2223.9722.0020.2521.691220.7520.2923.75M18PWB 目檢12.4714.7818.1319.0013.2415.4015.0918.4417.6216.812816.9210.5713.2913.699.7819.6215.0318.7516.4023.0122.1915.0921.9725.3820.414.0916.9724.1612.34PWB 分割 & 蓋印n Example: Hand solderi

55、ng for PWB of MPF82C.n Identify the operations.n Time first 10 cycles for each operation.n Calculate the required no. of cycles to be taken.2002/9/26SMT Training for Productivity54Determine No. of Cycles StationNo.OperationDescriptionFindings (sec)Required # cyclesAverage Time (sec)12345678910M15PWB

56、 分割 & 蓋印12312913814011911611210212113216122.25102127131125121118n Take the follows as an example, consider first 10 findings.n By N = 4R2 / A2(d2)2(x)2n R= (140-102) / 60 = 0.633n Avg. (x) = 123.2 / 60 = 2.053n For 95% confidence level, A = 0.05, d2 = 3.078n N = 4 (0.633)2 / (0.05)2(3.078)2(2.053)2

57、= 16n 6 additional cycles should be time taken.2002/9/26SMT Training for Productivity55Extend the Time StudyStation No.Average time (sec)Performance RatingNormal Time (sec)FrequencyManpowerUnit Normal Time (sec)M15122.250.9110.038113.75M1648.910.9546.461315.49M1720.750.918.681118.68M1816.92116.92111

58、6.92n Determine performance rating for each operation.n Normal time = avg. time X performance rating n eg. For M15, normal time = 122.25 X 0.9 = 110.03sn Identify frequency and manpower for each operation.n Unit normal time = normal time / (frequency x manpower) n eg. Unit normal time = 110.03 / (8 X 1) = 13.75seg.200