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,按一下以編輯母片標題樣式,按一下以編輯母片,第二層,第三層,第四層,第五層,2002/9/26,SMT Training for Productivity,*,Industrial Engineering :Work Design,Prepared by Ken Leung,2002/9/26,1,SMT Training for Productivity,Work Design,Methods Improvement,Ergonomics,Assembly line balancing,Principles of motion economy,Various type of charts,Work measurement,Time study,Activity sampling,2002/9/26,2,SMT Training for Productivity,Ergonomics,Definition,Apply 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.,2002/9/26,3,SMT Training for Productivity,Objectives,To enhance the work effectiveness and efficiency.,Increased convenience of use,Reduced errors,Increased productivity,To enhance human values.,Improved safety,Reduced fatigue and stress,Increased comfort,Greater user acceptance,Increased job satisfaction,Improved quality of life,2002/9/26,4,SMT Training for Productivity,Twelve Principles of Ergonomics,1.,Work in neutral postures,eg. Wrist rests for keyboard and mouse.,2. Reduce excessive forces,eg. Boxes with handholds for carrying.,2002/9/26,5,SMT Training for Productivity,Ergonomics Principles,3.,Keep everything in easy reach,eg. Keep materials within the “reach envelope” of the arm.,2002/9/26,6,SMT Training for Productivity,Ergonomics Principles,4.,Work at proper heights,eg. Heavy work should be performed lower than elbow height; precision work should be higher.,2002/9/26,7,SMT Training for Productivity,Ergonomics Principles,5.,Reduce excessive motions,eg. Use power screwdriver.,6. Minimize static load,eg. Use a pencil grip.,2002/9/26,8,SMT Training for Productivity,Ergonomics Principles,7.,Minimize pressure points,eg. Provide padding for hand grips.,8. Provide clearance,eg. Provide visual access,(carton delivery).,2002/9/26,9,SMT Training for Productivity,Ergonomics Principles,9.,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.,2002/9/26,10,SMT Training for Productivity,Ergonomics Principles,11.,Make displays and controls understandable,eg. Clicking is easier than memorizing commands.,12. Reduce stress,eg. Design task to fit people,.,2002/9/26,11,SMT Training for Productivity,Anthropometry,Definition,Measurement of the human body and its biomechanical characteristics.,Biomechanical refers to the mechanical (machine-like) capabilities of the human skeleton-muscular systems.,Measures our sizes and how we move and move easily.,Need of Anthropometry,We are not in the same size.,Poor design for mechanical abilities of the human body can lead to discomfort or injury.,Eg. Height of keyboard for a computer.,2002/9/26,12,SMT Training for Productivity,Anthropometric Data,Static measures, are used to determine size and spacing requirements of work space, eg., height, weight, seat to elbow height, and wing span.,Dynamic measures, are used to match the dynamic characteristics of controls to user, eg., range of motion for various joints, and strength of fingers.,2002/9/26,13,SMT Training for Productivity,Anthropometric Data,The anthropometric data is performed in normal distribution.,50th percentile is the most of the population.,5th and 95th percentiles are the extremes.,2002/9/26,14,SMT Training for Productivity,How to use anthropometric data,Design for extremes,A standard is to design to fit 5th or 95th percentiles of the population,.,Design for most of the population,50th percentile of the population should be used.,Make the design adjustable,The design can fit 5th to 95th percentiles of the population.,2002/9/26,15,SMT Training for Productivity,Examples,Design aims,Design examples:,Examples of measurements to consider:,Users that the design should accommodate:,Easy reach,Shelving,Arm length, shoulder height,Smallest user:,5,th,percentile,Adequate clearance to avoid unwanted contact or trapping,Cinema seats,Shoulder or hip width, thigh length,Largest user:,95,th,percentile,A comfortable and safe posture,Worksurface heights,Elbow height, sitting eye height, elbow height (sitting or standing),Most of the users:,50,th,percentile,Special fitting,Headphones,Head circumference,Maximum range:,5,th,to 95,th,percentile (adjustable design),2002/9/26,16,SMT Training for Productivity,Assembly Line Balancing,Equalize workload among the assemblies.,Identify the bottleneck operation.,Establish the speed of the assembly line.,Determine the number of work stations.,Determine the labor cost of assembly.,Establish the percent workload of each operator.,Assist in plant layout.,Reduce production cost.,2002/9/26,17,SMT Training for Productivity,Table for Assembly Line Balancing,No.,Operation,R-Value,Cycle time,#,stations,Avg. cycle time,%,Load,Hrs / 1000,Pcs. / hr,A1,Sub-assembly,0.216,0.21,1,0.21,100,3.5,285,A2,Assembly,0.216,0.441,3,0.147,70,10.5,95,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.,1,2,3,4,5,6,7,2002/9/26,18,SMT Training for Productivity,Items for Assembly Line Balancing Table,R-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-value,Average cycle time:,= Cycle time / # stations,1,2,3,4,2002/9/26,19,SMT Training for Productivity,Items 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 will save 1% for all stations.,The less percent loaded, the more desirable to be sub-assembled or combined.,5,2002/9/26,20,SMT Training for Productivity,Items for Assembly Line Balancing Table,Hours / 1000 :,The hours per 1000 units produced.,Choose the bottleneck station.,= (Avg. cycle time / 60 mins) x 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 1000,6,7,2002/9/26,21,SMT Training for Productivity,Improve Assembly Line Balancing,Calculate the Line Balance rate,Reducing the bottleneck station.,Combining the bottleneck station with an operation in front or behind.,Combining other operations to eliminate one of them.,2002/9/26,22,SMT Training for Productivity,Example: Original Line Balance,No.,Operation,R-Value,(mins),Cycle time,(mins),#,stations,Avg. cycle time (mins),%,Load,Hrs / 1000,Pcs. / hr,1,Place bottom housing on line and lubricate,0.25,0.200,1,0.200,80,4.17,240,2,Assemble parts 3, 4, & 5,0.25,0.250,1,0.250,100,4.17,240,3,Assemble parts 6 & 7 together and place sub-assembly in housing,0.25,0.305,2,0.153,61,8.34,120,4,Drive 6 bolts holding sub-assembly in bottom housing,0.25,0.600,3,0.200,80,12.50,80,5,Get vent cover & cement in place assembly to bottom housing,0.25,0.198,1,0.198,79,4.17,240,6,Get top housing, apply cement & assemble to bottom housing,0.25,0.290,2,0.145,58,8.34,120,7,Place in carton & in master carton (6 per) and aside to pallet,0.25,0.625,3,0.208,83,12.50,80,Total,13,1.354,Producing new plastic charger; 1200 units per 8-hrs shift,(with 300 mins effective).,2002/9/26,23,SMT Training for Productivity,Example: Original Line Balance,Original line balance rate,= total cycle time / highest cycle time station x no. of stations,= 1.354 / (0.25 x 7),=,77.4%,Pcs./hr = 60 / 0.25 = 240,Improve the bottleneck station by combining with an operation in front or behind.,Combine and eliminate work steps.,Re-design the jig & fixture.,Operations,Bottleneck or 100% load station,2002/9/26,24,SMT Training for Productivity,Example: Improved Line Balance,No.,Operation,R-Value,(mins),Cycle time,(mins),#,stations,Avg. cycle time (mins),%,Load,Hrs / 1000,Pcs. / hr,1 & 2,Place bottom housing on line, lubricate, & assemble parts 3, 4, & 5.,0.25,0.450,2,0.225,98,7.63,131,3 & 4,Assemble parts 6 & 7 together. Place in housing & drive 6 bolts holding sub-assembly to housing.,0.25,0.905,4,0.226,99,15.26,65,5,Get vent cover & cement in place in bottom housing.,0.25,0.198,1,0.198,86,3.82,262,6 & 7,Get top housing, apply cement & assemble to bottom housing, pack out.,0.25,0.915,4,0.229,100,15.26,65,Total,11,0.878,Improved line balance,2002/9/26,25,SMT Training for Productivity,Example: Improved Line Balance,Improved line balance rate,= total cycle time / highest cycle time station x no. of stations,= 0.878 / (0.229 x 4),=,95.9%,Pcs/hr = 60 / 0.229 = 262,Increase in output with decrease in no. of workstations.,Operations,Bottleneck or 100% load station,2002/9/26,26,SMT Training for Productivity,Principles of Motion Economy,Guidelines for efficient and effective work station design.,Summarized to 4 major elements:,Elimination,Combination,Rearrangement,Simplification,2002/9/26,27,SMT Training for Productivity,Elimination,Eliminate all possible jobs, steps, or motions.,Eliminate irregularities in job.,Eliminate the use of hand as holding device.,Eliminate abnormal motions.,Eliminate the use of muscles to maintain a fixed position.,Eliminate muscular force by using power tools.,Eliminate danger.,Eliminate idle time.,2002/9/26,28,SMT Training for Productivity,Combination,Replace with one continuous short motion.,Combine tools, controls, and motions.,Rearrangement,Distribute the work evenly between two hands.,Shift work from the hands to the eyes.,Arrange for a straight forward order of work.,2002/9/26,29,SMT Training for Productivity,Simplification,Reduce eye travel.,Keep work in the normal work area.,Shorten motions.,Adapt handles, levers, pedals, buttons, etc., to human dimensions and musculatures.,2002/9/26,30,SMT Training for Productivity,Applying the Principles of Motion Economy,1.,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 ink bottle.,2002/9/26,31,SMT Training for Productivity,Applying the Principles of Motion Economy,2.,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.,2002/9/26,32,SMT Training for Productivity,Applying the Principles of Motion Economy,3.,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.,2002/9/26,33,SMT Training for Productivity,Applying the Principles of Motion Economy,4.,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 own gravity,.,2002/9/26,34,SMT Training for Productivity,Applying the Principles of Motion Economy,6.,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 and hands.,2002/9/26,35,SMT Training for Productivity,Applying the Principles of Motion Economy,8.,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.,2002/9/26,36,SMT Training for Productivity,Various types of charts,Used as record techniques,Outline process charts:,Overview of a process with graphical representation.,Show principal operations () and inspections (,).,Assist in the plant layout design, design of product, or machinery processes.,2002/9/26,37,SMT Training for Productivity,Various types of charts,Flow process chart:,Activities of men, material or equipment.,Two or more subjects can be presented alongside each other to show their interdependence.,Activities are divided by 5 functions, operation (), transport (,), storage (,), delay (,D,), inspection (,).,Only the activities of particular subject, either man, material, or equipment, are recorded on a single chart.,2002/9/26,38,SMT Training for Productivity,Example,Flow process chart:,Inspecting and marking,incoming parts,(original method),2002/9/26,39,SMT Training for Productivity,Example,Flow process chart:,Inspecting and marking,incoming parts,(improved method),2002/9/26,40,SMT Training for Productivity,Various types of charts,Tow-handed process chart:,Useful in showing idle time by either hand.,Activities of a workers two hands.,Simultaneous movements by both hands appear opposite each other.,Description of the activities represented by the symbols should be inserted.,2002/9/26,41,SMT Training for Productivity,Example,Two-handed process,chart:,Cutting glass tubes,(original method),2002/9/26,42,SMT Training for Productivity,Example,Two-handed process,chart:,Cutting glass tubes,(improved method),2002/9/26,43,SMT Training for Productivity,Various types of charts,Multiple activity charts:,Consider on the activities of a subject in relation to one or more others.,Show up clearly ineffective time within the process.,Useful in finding the best sequence of carrying out the various parts of the work.,Operation / machine chart,shows the interrelationship of the operator and the machine.,2002/9/26,44,SMT Training for Productivity,Example,Multiple activity chart ,worker and machine:,Finish mill casting,(original method),2002/9/26,45,SMT Training for Productivity,Example,Multiple activity chart ,worker and machine:,Finish mill casting,(improved method),2002/9/26,46,SMT Training for Productivity,Time Study,Most common technique for setting time standards.,Useful for repetitive work.,Provide standard rate of working.,A means of assessing the amount of rest that should be associated with the job.,2002/9/26,47,SMT Training for Productivity,Time Study: Procedures,1.,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.,8. Apply allowances.,9. Check logic.,10. Publish the time standard.,2002/9/26,48,SMT Training for Productivity,Time Study: Focus Points,Extend the time study,Calculate average observed time.,Determine performance rating.,Calculate normal time:,-,Normal Time = average observed time x performance rating,Find out frequency (how many times a task is performed within a time period).,Calculate unit normal time.,2002/9/26,49,SMT Training for Productivity,Time Study: Focus Points,Determine the number of cycles,N = number of cycles,R = range of the sample of observations (in minutes),A = required precision (+/- 5% or 10%),d,2,= statistical constant (3.078 for 95% confidence level),x,= average time (in minutes),2002/9/26,50,SMT Training for Productivity,Time Study: Focus Points,Performance rating,Rating is the process of adjusting the time taken by an individual operator to what could be expected from a normal operator.,Four major factors: skill, consistency, working conditions, and effort.,Effort is the most important.,Effort is the operators speed, and is measured based on the normal operator working at 100%.,2002/9/26,51,SMT Training for Productivity,Time Study: Focus Points,Relaxation allowance,It is the allowance for the periodic stops for personal needs or fatigue.,Example: going to washroom; getting a drink.,Contingency allowance,It is a small allowance of time which may be included in a standard time to meet expected items of delays.,Occurs infrequently or irregularly.,Example: interruptions by supervisors; changing materials.,2002/9/26,52,SMT Training for Productivity,Time study: Example,Station No.,Operation,Description,Findings (sec),Required,# cycles,Average Time (sec),1,2,3,4,5,6,7,8,9,10,M15,PWB,分割,&,蓋印,123,129,138,140,119,116,112,102,121,132,16,122.25,102,127,131,125,121,118,M16,26 pin,電容,振盪器,接地線焊接,48.65,51.14,48.69,50.81,46.50,49.16,50.00,48.28,43.78,52.06,10,48.91,M17,電感焊接,18.59,19.01,20.40,20.10,19.75,18.22,23.97,22.00,20.25,21.69,12,20.75,20.29,23.75,M18,PWB,目檢,12.47,14.78,18.13,19.00,13.24,15.40,15.09,18.44,17.62,16.81,28,16.92,10.57,13.29,13.69,9.78,19.62,15.03,18.75,16.40,23.01,22.19,15.09,21.97,25.38,20.4,14.09,16.97,24.16,12.34,PWB,分割,&,蓋印,PWB,分割,&,蓋印,Example: Hand soldering for PWB of MPF82C.,Identify the operations.,Time first 10 cycles for each operation.,Calculate the required no. of cycles to be taken.,2002/9/26,53,SMT Training for Productivity,Determine No. of Cycles,Station,No.,Operation,Description,Findings (sec),Required,# cycles,Average Time (sec),1,2,3,4,5,6,7,8,9,10,M15,PWB,分割,&,蓋印,123,129,138,140,119,116,112,102,121,132,16,122.25,102,127,131,125,121,118,Take the follows as an example, consider first 10 findings.,By N = 4R,2,/ A,2,(d,2,),2,(,x,),2,R= (140-102) / 60 = 0.633,Avg. (,x,) = 123.2 / 60 = 2.053,For 95% confidence level, A = 0.05, d2 = 3.078,N = 4 (0.633),2,/ (0.05),2,(3.078),2,(2.053),2,= 16,6 additional cycles should be time taken.,2002/9/26,54,SMT Training for Productivity,Extend the Time Study,Station No.,Average time (sec),Performance Rating,Normal Time (sec),Frequency,Manpower,Unit Normal Time (sec),M15,122.25,0.9,110.03,8,1,13.75,M16,48.91,0.95,46.46,1,3,15.49,M17,20.75,0.9,18.68,1,1,18.68,M18,16.92,1,16.92,1,1,16.92,Determine performance rating for each operation.,Normal time = avg. time X performance rating,eg. For M15, normal time = 122.25 X 0.9 = 110.03s,Identify frequency and manpower for each operation.,Unit normal time = normal time / (frequency x manpower),eg. Unit normal time = 110.03 / (8 X 1) = 13.75s,eg.,2002/9/26,55,SMT Training for Productivity,Establish Time Standard,Define allowances:,Personal usually 5%,Fatigue minimum 5%,Delay usually 3 %,Identify bottleneck station.,Standard time,= cycle time of the bottleneck / (1- 5% - 5 % - 3 %),= 18.68 / 0.87,= 21.47s,Pcs./Hr = 3600 / 21.47 = 167,Bottleneck,2002/9/26,56,SMT Training for Productivity,Activity Sampling,A technique in which a number of successive observations are made over a period of time of one or a group of machines, processes, or workers.,Each observations records what is happening.,A measure of the percentage of time for a particular activity or delay.,2002/9/26,57,SMT Training for Productivity,When to use and why?,Assess productive and non-productive time as an aid to setting allowance.,Determine the job content as part of a job analysis.,Estimate managerial needs, equipment needs or the cost of various activities.,Help workers make better use of their time.,2002/9/26,58,SMT Training for Productivity,Activity Sampling: steps,1.,Establish the purpose and goal of the study.,2. Identify the elements.,eg. Work, idle, material handling, etc.,3. Estimate the ratio percent of the elements.,eg. May be estimated by pilot study.,4. Determine the level of accuracy and confidence.,eg. Level of accuracy=+/-5%, confidence level=95%.,2002/9/26,59,SMT Training for Productivity,Activity sampling: st
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