3.1.1 . lean manufature
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What's lean manufacturing
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3.1.1 . lean manufature
- 1. Introduction to Lean Manufacturing © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com
- 7. The Origin of Lean Manufacturing Discussion question: Who created the Toyota Production System? © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com
- 8. The Creator of the Toyota Production System © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com
- 11. What is Lean Manufacturing? A systematic approach to the identification and elimination all forms of waste from the value stream. © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com
- 12. Concept of Friction, Waste, or Muda Understanding of friction, waste, or muda is the foundation of the lean Manufacturing. © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com
- 15. Waste is Often Built Into Jobs © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com Pre-Gilbreth Bricklaying
- 17. Post-Gilbreth Brick Laying © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com The solution is obvious (in retrospect), but first we have to know that we have a problem!
- 18. Another Example: Fabric Folding © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com Redesign of this job to eliminate the need to walk doubled its productivity. We will see that material waste also hides in plain sight.
- 19. Material Waste Hides in Plain Sight © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com Cleaning Tank 1 Cleaning Tank 2 Dirty parts Clean parts Clean Water Discard water Clean Water The parts get clean, so no one questions this. What is wrong with this picture?
- 20. Why Not Make the Water Work Twice? 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com Cleaning Tank 1 Cleaning Tank 2 Dirty parts Clean parts Discard water Clean Water The almost clean water from the second tank is good enough for use in the first tank. Water usage can be cut 50 percent. ©
- 21. Spin Coating of Semiconductor Wafers © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com The product is the coated wafer, and "the job has always been done this way" in the semiconductor industry. This is how waste hides in plain view.
- 30. Gantt Chart Modification © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com Only machining is value-adding time. This Gantt format of the cycle time makes non-value-adding time highly visible.
- 37. Example: Spin Coating of Semiconductor Wafers © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com The control surface analysis forces the waste to become visible, and causes people to ask if there is a practical way to avoid it. Wafers and Photoresist Photoresist Coated Wafers Process Control Surface
- 38. Example: Machining © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com The waste that is usually taken for granted (metal chips and used cutting fluid) suggests product or process redesign to reduce machining. Metal billets and cutting fluid Metal turnings and cutting fluid Product Process Control Surface
- 40. Lean Manufacturing Techniques Some principles and activities for lean manufacturing © 2009, Levinson Productivity Systems, P.C. www.ct-yankee.com
Editor's Notes
- As we proceed through the presentation, we will see many specific advantages of lean Manufacturing. Lower production costs and shorter cycle times encompass the key competitive advantages. "Insurmountable" is not an exaggeration . The only thing that can compete with a lean Manufacturing system is another lean Manufacturing system. Make-to-order (facilitated by shorter cycle times and JIT) crushes make-to-forecast through lower cost and better customer satisfaction. Comprehensive lean Manufacturing crushes cheap foreign labor. It was, in fact, developed with this issue in mind. Lean Manufacturing can thus preserve American manufacturing capability, upon which our nation's security and standard of living depend. (3) Comprehensive lean Manufacturing beats Six Sigma any day of the week. (Lean Manufacturing actually includes many elements of Six Sigma, such as standardization and best practice deployment.) The Ford Motor Company continued to expand its sales during the post-World War I depression by using lean Manufacturing. A lean company is secure even during "bad times." "What has Six Sigma done for Motorola lately (2000-2002)?" (4) Lean Manufacturing includes total quality management (TQM).
- The Ford Motor Company (and the industries that grew to support it) was directly responsible for making the United States the wealthiest and most powerful nation on earth. The U.S. surpassed the British Empire some time during the 1910s. During the Model T's 19 years of production, it created more prosperity than the estimated wealth of 35 of the country's 48 states (Ford, 1930, Moving Forward ). This figure did not include railway workers, rubber workers, oil workers, and others for whom the Model T created jobs. When the going got tough, the Ford lean Manufacturing system kept going. "What has Six Sigma done for Motorola lately (2000-2002)?" The Ford Motor Company sold 1.25 million cars during the 1920-1921 depression that followed the First World War and the 1918 influenza epidemic: five times as many cars as the company sold during 1913-1914 . Lean Manufacturing is more comprehensive and global in outlook than Six Sigma. Lean Manufacturing's goal is to root out all forms of waste. Remember, however, that lean actually incorporates aspects of Six Sigma, so the two systems are compatible.
- My Life and Work (1922) described all the basic principles of JIT: We have found in buying materials that it is not worth while to buy for other than immediate needs. We buy only enough to fit into the plan of production, taking into consideration the state of transportation at the time. If transportation were perfect and an even flow of materials could be assured, it would not be necessary to carry any stock whatsoever. The carloads of raw materials would arrive on schedule and in the planned order and amounts, and go from the railway cars into production. That would save a great deal of money, for it would give a very rapid turnover and thus decrease the amount of money tied up in materials. With bad transportation one has to carry larger stocks. Materials arrive exactly, and only, when the production line needs them. Materials go, not from dock to stock, but from dock to factory floor. JIT requires reliable transportation and a supporting logistics system. Bad transportation (e.g. lack of a good freight management system) requires the plant to keep more inventory. Inventory reduction frees capital. Cycle time reduction frees capital.
- A dollar's worth of Ford stock purchased in 1903 returned $2500 when Ford bought his stockholders out in 1919.
- Lean Manufacturing was directly responsible for making the United States the wealthiest and most powerful nation on earth during the early twentieth century. Enormous growth in U.S. productivity caused the United States to surpass the British Empire in wealth and military power. Lean Manufacturing is the only way to protect American manufacturing capability and preserve the nation's affluence and military security.
- The brick weighs about five pounds (2.3 kg). How much does the worker actually raise and lower every time he bends over for another brick? This animation illustrates the virtue of videotaping workplace activities. The people who are doing the job may have become accustomed to the waste that is built into the job but, when they watch themselves in the videotape, the waste may become obvious.
- "But all [employees] took two steps to the right to secure their cloth, returned to the tables, folded the stuff and deposited it on another pile two steps to the left. That had always been the practice; no one had ever thought to question it." Edward Mott Woolley example from The System Company. 1911. How Scientific Management is Applied . London: A. W. Shaw Company Ltd. The animation illustrates the value of videotaping a job, not to measure the performance of individual employees, but to assess the job's design for inefficiencies.
- Countercurrent flow is standard in extraction, absorption, and leaching operations, where it is desirable to concentrate the dissolved material in the solvent.
- Researchers are now investigating extrusion spin coating as a way to reduce this waste. http://dspace.mit.edu/handle/1721.1/8694 "Spin coating is the prevalent coating method to produce the required thickness and uniformity, but it typically wastes over 90% of the photoresist applied . A more efficient method needs to be developed for two reasons. The first is that 80% of the photoresist is an environmentally hazardous solvent. The second is the cost increase of photoresist."
- "I believe that the average farmer puts to a really useful purpose only about 5 per cent. of the energy he expends. … Not only is everything done by hand, but seldom is a thought given to a logical arrangement. [Time for a kaizen blitz?] A farmer doing his chores will walk up and down a rickety ladder a dozen times. He will carry water for years instead of putting in a few lengths of pipe . His whole idea, when there is extra work to do, is to hire extra men. He thinks of putting money into improvements as an expense . … It is waste motion— waste effort— that makes farm prices high and profits low" (Henry Ford, 1922, My Life and Work ).
- (1) Overproduction "Just-in-case" production driven by long-term market forecasts, instead of just-in-time Dysfunctional performance measurements that demand that personnel and equipment keep busy. (2) Waiting: time in queue Aggravated by batch-and-queue operations. (Heat-treatment seems notorious for this.) Alleviated by single-unit processing (3) Transportation Hand trucks and forklifts for moving parts from one part of the factory to another: no value added, opportunity for handling damage. Transportation introduces cycle time and lead time, e.g. container ships from China add six or seven weeks . Mortal enemy of make-to-order, assemble-to-order, and JIT Defects are not discovered promptly
- Imai, Masaaki. 1997. Gemba Kaizen . New York: McGraw-Hill
- We recommend an understanding of this concept as a basic skill that everybody needs to know.
- See Levinson, Beyond the Theory of Constraints (2007, Taylor-Francis) for more about cycle time accounting.
- The importance of this observation cannot be overemphasized. Today, avoidance of disposal costs is an incentive for green manufacturing. Ford found it profitable to find uses for waste (or avoid its production in the first place) even though he could have legally dumped it into the atmosphere or river.
- At the basic skill level, frontline workers need to recognize that anything that is thrown away represents wasted material, and possibly disposal costs. At the intermediate skill level, managers and engineers should understand the control surface concept, and the fact that all inputs and outputs must balance. Levinson, William A. "Waste Management: Using a bill of outputs to eliminate excess." APICS, The Performance Advantage , January 2005 (33-35) We recommend this as an intermediate-level tool for use by facilitators, engineers, and managers.
- There is admittedly no guarantee that the waste can in fact be avoided or eliminated once it is recognized. The usual situation is, however, that there is NO chance to eliminate it because no one recognizes its presence in the first place.
- At Henry Ford's River Rouge auto plant during the late 1920s or early 1930s, workers noticed that a machining process reduced 25 percent of the aluminum stock to chips. The product or process was redesigned to reduce the waste to 2 percent, even though the chips were presumably recyclable.
- Example: power source regeneration means that, when machine tools stop, their motors act as generators by recovering the mechanical energy as electricity. The concept is similar to that of the Toyota Prius, but the technology has been available in machine tools before the Prius became available. See Koelsch, James R. "Machine Efficiency = Energy Efficiency," Manufacturing Engineering , September 2008, pp. 121-130.
- Henry Ford, My Life and Work (1922), on DFM: "Start with an article that suits and then study to find some way of eliminating the entirely useless parts. This applies to everything— a shoe, a dress, a house, a piece of machinery, a railroad, a steamship, an airplane. As we cut out useless parts and simplify necessary ones, we also cut down the cost of making." "But also it is to be remembered that all the parts are designed so that they can be most easily made." Ricoh Copier: an improvement during the design phase has a 100:1 payoff. A process improvement has a 10:1 payoff. Correction of a manufacturing problem has a 1:1 payoff. (Lorenzen, Jerry. 1992. "Quality Function Deployment." Presentation to the Mid-Hudson Chapter, ASQC, 05/26/92) DFM ties in with quality function deployment (QFD), also known as the "house of quality." QFD brings "the voice of the customer" into the design process.
- Rudyard Kipling's The 'Eathen describes the general idea: The 'eathen in 'is blindness bows down to wood an' stone; 'E don't obey no orders unless they is 'is own; 'E keeps 'is side-arms awful: 'e leaves 'em all about, An' then comes up the regiment an' pokes the 'eathen out. All along o' dirtiness, all along o' mess, All along o' doin' things rather-more-or-less, All along of abby-nay, kul, an' hazar-ho, Mind you keep your rifle an' yourself jus' so! … Gettin' clear o' dirtiness, gettin' done with mess, Gettin' shut o' doin' things rather-more-or-less; Not so fond of abby-nay, kul, nor hazar-ho, Learns to keep 'is rifle an' 'isself jus' so! abby-nay = "Not now." kul = "Tomorrow." hazar-ho = "Wait a bit." (1) Clearing Up: Your wastebasket is your friend. Disney theme parks have plenty of waste receptacles. At Ford's River Rouge plant, a waste container was within six steps of any position (Norwood, 1931. Ford: Men and Methods ). Unwanted but serviceable equipment can be auctioned off on E-bay. Three-tier classification Frequently-used items at workstation Regular use: near workstation Rare use: keep outside the work area (2) Arranging: a place for everything, and everything in its place (3) Neatness: Keeping everything clean makes it easier to locate leaks and dropped parts. It also keeps dirt out of the equipment and the product. (4) Discipline: includes scheduled preventive maintenance: Described explicitly by Frederick Winslow Taylor in 1911 (5) Ongoing improvement: Holding the gains through standardization and best practice deployment
- Smith, Wayne. 1998. Time Out: Using Visible Pull Systems to Drive Process Improvements . New York: John Wiley & Sons. Suzaki, Kyoshi. 1987. The New Manufacturing Challenge . New York: The Free Press Caravaggio, Michael: "Total Productive Maintenance" in Levinson, William (editor). 1998. Leading the Way to Competitive Excellence: The Harris Mountaintop Case Study . Milwaukee, WI: ASQ Quality Press. Principles for visual controls, per Caravaggio (in Levinson, 1998) Communication: written communications must be easily accessible. Visibility: communication uses pictures and signs. Consistency: every activity uses the same conventions. Traffic signs are an example. Stop signs are the only red octagonal signs, yield signs are triangular, and so on. Detection: alarms and warnings announce abnormalities. Fail-safing: this prevents mistakes and abnormalities.
- See Levinson, William, and Rerick, Raymond. 2002. Lean Manufacturing: A Synergistic Approach to Minimizing Waste . Milwaukee: ASQ Quality Press Ford Highland Park plant (1915): the accumulation of inventory where it didn't belong, e.g. in a work slide or on a conveyor belt, was easily visible. It was evidence of a stoppage or other problem. "As soon as the roll-ways were placed the truckers were called off, the floor was cleared, and all the straw boss had to do to locate the shirk or operation tools in fault, was to glance along the line and see where the roll-way was filled up" (Arnold, Horace Lucien, and Faurote, Fay Leone. 1915. Ford Methods and the Ford Shops . New York: The Engineering Magazine. Reprinted 1998, North Stratford, NH: Ayer Company Publishers, Inc.).
- Reference: Smith, Wayne. 1998. Time Out: Using Visible Pull Systems to Drive Process Improvements . New York: John Wiley & Sons. "For each constituent operation of an order an instruction card corresponding to the standard order is written at the time the work is planned, and, when issued to the workman, it is hung in plain sight in a tin rack at the workman's bench . To insure definitely the complete occupation of the employee's time three jobs are assigned him; he is working on one, the second is ready— all materials and appliances at hand, and the third is either ready or the stock is in the material or the milling department. When a job is completed, the mechanic hangs his card on a hook on the lower right hand corner, moves up the other two, and goes on with his work. … The rack always shows the foreman what the man is doing, and calls attention to the jobs ahead, so that it is of the very greatest value in coordinating the work of the various departments. " (Frederick G. Coburn, "Laying Out Work for Each Man," in The System Company. 1911. How to Get More Out of Your Factory . London: A. W. Shaw Company, Ltd.) Furthermore, "…it is also necessary that each man get through with his job in time for the next man to take it up, for that next man isn't going to be caught loafing if he values his job. [This wording reflects management attitudes of the early twentieth century, but note that inventory does not decouple downstream operations from stoppages.] And the work must be done right, or the next man will kick [complain], lest the boss find him with a piece of imperfect work. [There is little or no inventory in which defects can hide for long.] The whole thing becomes an interlocking and smoothly working mechanism if correctly planned and supervised: and the most trouble occurs under the conditions producing apparently the smoothest running under the old system ."
- The chemical industry has some of the most easily-controllable processes in existence. They are (ideally) pure flow operations Chemical engineers prefer the plug flow reactor (PFR) and continuous stirred tank reactor (CSTR) over the batch reactor. They are amenable to automatic process controls, e.g. proportional-integral-derivative (PID) controllers. In discrete-item manufacture, single-unit processing is the closest approximation to a continuous flow operation.
- The golf analogy is a very good one. Remember that a punch adds value to the part only during the split second in which it actually strikes the part. A drill or lathe adds value only when the tool is in contact with the piece and is cutting metal. Theory of Constraints (Goldratt): you can increase capacity only by elevating the constraint operation. Cycle time can, however, be reduced anywhere in the process. Eliminate batching and queuing Transportation adds cycle time but no value. Single-minute exchange of die (SMED) reduces setup times and allows smaller batches to be run economically Processes can be changed to reduce cycle time. Selection of the right alloy can eliminate a heat-treatment step. The advantages of a short cycle time can be enormous. Make-to-order instead of make-to-forecast! No need to guess what customers will want several months from now. Adams Citrus Nursery's continuous flow greenhouse, using "Citripots." Lead time 9 months instead of 3 years, trees could be grown to order for orchards. Better responsiveness to customer needs
- "Instruction Card for Lathe Work," from Frederick Winslow Taylor's Shop Management (1911). The left-hand column is for "operations connected with preparing to machine work on lathes and with removing work to floor after it has been machined." It therefore includes setting up the lathe, and loading and unloading the work. These are non-value-adding and, per SMED, should be reduced or externalized. The right-hand column is for "operations connected with machining work on lathes." Taylor apparently focused his efforts on making these activities more efficient (as opposed to reducing setup). The value-adding operations of his era suffered, however, from the false economy of trying to maximize the tool's life at the expense of productivity. Taylor said to machine the work as quickly as possible, and regrind the tools as necessary. Taylor and J. Maunsel White developed the Taylor-White process for treating tool steel. Per Taylor's Shop Management (1911), When one realizes that the cutting speed of the best treated air hardening steel is for a given depth of cut, feed, and quality of metal being cut, say sixty feet per minute, while with the same shaped tool made from the best carbon steel and with the same conditions, the cutting speed will be only twelve feet per minute, it becomes apparent how little the necessity for rigid standards is appreciated.
- SMED also increases the tool's capacity by reducing setup time. Per Goldratt's Theory of Constraints, however, this does not improve factory capacity unless the tool in question is the constraint. Note SMED's central role in cycle time reduction . When setup times are long, the factory is almost compelled to run large batches of parts to avoid breaking setups. Batch-and-queue is the mortal enemy of short cycle times because the parts spend most of their time waiting to be processed. Historical example of SMED: the preloaded musket cartridge. Measuring out the black powder charge from a powder horn is internal setup ; a hunter could not use his firearm while he was doing this. This aspect of setup could, however, be externalized by measuring the appropriate charge into a wooden cartridge. Sixteenth-century woodcuts show soldiers using such cartridges, and performing loading drills that incorporated motion efficiency principles. The paper-wrapped cartridge reduced non-value-adding handling even further by incorporating the powder charge, bullet, and wadding (the paper wrapping itself) into one package. It eliminated the need for the soldier to reach for the cartridge, bullet, and wadding separately. The ability to shoot more rapidly at targets that shot back was doubtlessly an incentive to develop methods that industry adopted centuries later, and Frank Gilbreth recognized this in his Motion Study (1911).
- Seen at a health clinic at O'Hare Airport while getting a flu shot (October 2002): syringes have needle caps attached to them. After the injection is given, the needle is capped immediately. The nurse does not have to go to a sharp-object disposal unit to make the needle safe. It's estimated that handwritten prescriptions kill up to 25,000 patients per year ("Message to physicians: Better read than dead." 2000. Wilkes-Barre Times Leader , 25 October 2000). ISO 9000 does not allow any uncontrolled handwritten work instructions. Recommendation (being done in some hospitals): the physician must enter the prescription into a computer. Check for unusual dosages (e.g. 100 instead of 10) Check for interactions Send unambiguous instructions to the pharmacy and possibly issue a bar code for the medication