Work Optimization Ch. 13

Work OptimizationCh. 13Dr. Ron LembkeSCM 4621/16How accurately can you measure?

1 mm = 1/251/32Calipers

1/640.05mmMicrometer = 0.01mm

CalipersLord Chancellor Micrometer

Accurate to 1/10,000Created when?1805Henry Maudslay 1771-1831Powder monkey at age 12, cabinet shop Joseph Bramas (hydraulic press) lock shopInvented (or pioneered) slide rest lathe Standardized screws

Block makingMachines for Marc Brunel, Used for 100 yearsWaited for American System

Beginning of StandardsBefore standardized parts, need Screws1860s Machine Tool industry: Silicon Valley of its dayAll screws custom made by tool & die shops according to what they thought bestWilliam Sellers: 1864 On a Uniform System of Screw Threads Sellers vs. Whitworth3 cutters & 2 lathes vs. 1 cutter & 1 latheSimple geometry vs. difficultRounded top vs. straight: ease of manufacturing, ease of assembly

Not Just What you KnowMachine tool makers didnt want to be commoditized like gun makersThe standard people expect to win usually does.Navy Board found it superior, asked Singer Sewing Machine, Baldwin Locomotive which would win (already adopted).Pennsylvania RR adopted (Sellers on the Board)British tanks & trucks couldnt be repaired in WWII because Britain adopted WhitworthEiji Toyodas Ambitious PlansPost-WWII Japanese industry in ruinsEarly 1950s toured Rouge plant2,500 cars in 13 years. Ford: 8,000 per dayCatch up to Americans in 4 years!Toyoda made delivery trucks and motorcycles, and not many of either

, the early yearsFirst two Toyotas imported to U.S. 1957

Elimination of Waste Knew they wouldnt beat U.S. with product innovation, concentrated on licensing patents, and producing more efficientlyCosts prevented mass-production, volume strategy of American firms.Find ways to reduce waste, costShigeo Shingo & Taiichi Ohno, pioneersOhno & Shingo

Couldnt Emulate GMGM huge batches in huge factoriesJapans area is 10% less than California and 70% agricultural.Put entire population of CA into 30% of state, then add 6 times as many people. (and you thought LA was crowded).Land extremely expensiveSprawling factories not an optionSmall BatchesGMs large batches require large amounts of storage space.GM produces in large batches because of significant setup costs.If Toyota had the same large setup costs, it could never afford small batches.Reduce setup cost to reduce batch size.GM didnt think of doing this.Two Pillars of Toyota SystemJust-in-Time: produce the right parts, at the right time, in the right quantityAutonomation: Automation with a human touch (make machine mistake-proof)Just-in-TimeDownstream processes take parts from upstream as they need.Like an American Supermarket:Get what you wantwhen you want itin the quantity you want.KanbanJapanese for signboardMethod for implementing JITIn order to produce, you need both material to work on, and an available kanban.Each work station has a fixed # kanbans.KanbanWorker 2 finishes a part, outbound moves over2 has a blue tag avaliable, so 2 gets another part to work on:2 takes off 1s green tag giving it back to 1, and puts on her blue tag and moves it into position.Flow of work32KanbanWhen 3 finishes a part, Finished parts move over one spotHe has to have a red tag available to put on,He gets a part from 2s outbound pile, And gives the blue back to 2Flow of work32KanbanWhen 3 finishes a part, Finished parts move over one spotHe has to have a red tag available to put on,He gets a part from 2s outbound pile, And gives the blue back to 23s production will be taken by 4, offstage right.Tag goes back into 3s binFlow of work32KanbanRed finishes his part next.

But 4 hasnt freed up any of the red kanbans, so there is nothing for 3 to work on now.3 could maintain his machine, or see if 4 needs help3232How is this Different?Processes can become idled (blocked) or starvedThis makes you painfully aware of problems in your system.Material moves through the system so quickly no in-process recordkeeping is needed.Total Quality ManagementNot a lot of parts to sift through to find a good oneCant afford high defect ratesSince low WIP, get quick feedback on errorsWIP LevelLess WIP means products go through system fasterreducing the WIP makes you more sensitive to problems, helps you find problems fasterStream and Rocks analogy:Inventory (WIP) is like water in a streamIt hides the rocksRocks force you to keep a lot of water (WIP) in the streamLowering Inventory Reduces Waste

WIP hides problemsLowering Inventory Reduces Waste

WIP hides problemsLowering Inventory Reduces Waste

Reducing WIP makesproblem very visibleSTOPLowering Inventory Reduces Waste

Remove problem, runWith less WIPLowering Inventory Reduces Waste

Reduce WIP again to findnew problemsImportance of FlowOhno was very clear about this:Kanban is a tool for realizing just-in-time. For this tool to work fairly well, the process must be managed to flow as much as possible. This is really the basic condition. Other important conditions are leveling the product as much as possible, and always working in accordance with standard work methods.-- Ohno, 1988, p. 3Setup ReductionCant afford to do huge runsHave to produce in small batchesToyota Die Change: 3 hours down to 3 SMED: under ten minutesTechniquesMake internal setups into ExternalEliminate AdjustmentsEliminate the SetupContinuous Process Improvement, anyone?

Lot Sizing

Takt time = available time (day) / Customer demand rate per day

Uniform Plant Loading (heijunka)Any changes to final assembly are magnified throughout production processSmoothingMaster production schedule: 10,000 /mo.500 day, 250 a shift480 minutes means 1 every 1.92 minutesSequencing:If mix is 50% A, 25% B, 25% C, produceA-B-A-C-A-B-A-C