【導(dǎo)讀】Drawinpencil(easytochange&reliable)avoidputer(timeconsuming). CycleTime(C/T). Changeovertime(C/O). Batchsize. Numberofoperators. Scraprate. Inventorylevels. C/T=45sec.

　　

【正文】 ls the mix of brackets it produces evenly over the shift, then the stamping press (with a shortened setup time) will have plenty of time to react to the cell’s pull for leftdrive and rightdrive parts. It will have time to replenish what was taken away without the need for much inventory in the stamping supermarket. With leveling, which implies more frequent changeovers, the cell’s production mix of trays of brackets would look like this: 1st shift 2nd shift RLLRLLRLLRLLRLLRLLRLLRLLRLLRLLRLLRLLRLLRLLRLLR 35 KEY QUESTIONS FOR THE FUTURE STATE Question 7: What consistent increment of work should Acme release and take away at the pacemaker process? Returning all 46 kanbans (two shifts worth) to the cell at once would provide no sense of takt time to the cell. Batching the volume of work like this must be avoided. A natural increment of welding/assembly work in Acme’s case is the 60 second takt time x 20 pieces per tray = 20 minutes. This is the steeringbracket pitch, which corresponds to one kanban for one tray of 20 steering brackets. This pitch means that Acme will practice paced release of work instruction and paced withdrawal of finished goods at its weld/assembly cell. Each column in Acme’s steeringbracket loadleveling box represents a 20minute pitch increment. The two rows are designated for leftdrive and rightdrive kanban. Every 20 minutes, a material handler brings the next kanban (the next increment of work) to the weld/assembly cell and moves the justfinished tray of brackets to the finished goods area. If a tray is not finished at the 20minute pitch increment, then Acme knows there is a production problem. 36 KEY QUESTIONS FOR THE FUTURE STATE Question 8: What process improvements will be necessary for Acme’s value stream to flow as the future state design describes? Achieving the material and information flows we envision for Acme stamping requires the following process improvements: Reduction in changeover time and batch sizes at the stamping press, to allow faster response to downstream usage. Elimination of the long time (10 minutes) required to change between leftdrive and rightdrive fixtures in welding, to make possible continuous flow and mixed production from welding through assembly. Improvement in ondemand uptime of the second spotweld machine, as it will now be tied to other processes in a continuous flow. Elimination of waste in the weld/assembly cell, to reduce total work content down to 168 seconds or less (Which allows use of 3 operators at the current demand level.) 37 FUTURE STATE MAP FIRST VIEW Source: Learning to See Value Stream Mapping to Add Value and Eliminate Muda, Mike Rother and John Shook 2 shifts 18,400 pieces/mo 12,000 “L” 6,400 “R” Tray = 20 pieces 1 x daily WELD + ASSY Takt = 60 seconds 2 shifts C/O = 0 Uptime = 100% total work content = 168 seconds SHIPPING Staging First View of the FutureStateMap Showing Takt Time, Weld/Assembly Cell and Finished Goods Supermarket State Street Assembly STAMPING L R 20 38 FUTURE STATE MAP SECOND VIEW Source: Learning to See Value Stream Mapping to Add Value and Eliminate Muda, Mike Rother and John Shook PRODUCTION CONTROL 2 shifts 18,400 pieces/mo 12,000 “L” 6,400 “R” Tray = 20 pieces 6week Forecasts Weekly fax Daily (Milk Run) 1 x daily WELD + ASSY Takt = 60 seconds 2 shifts C/O = 0 Uptime = 100% total work content = 168 seconds SHIPPING Staging Second View of FutureState Map Showing Stamping and Raw Material Supermarkets State Street Assembly STAMPING EPE = 1 shift 27,600 sec. avail. C/O 10 minutes Uptime = 85% Coils (at the press) Michigan Steel Co. tote coil coil batch L R 20 39 FUTURE STATE MAP THIRD VIEW Source: Learning to See Value Stream Mapping to Add Value and Eliminate Muda, Mike Rother and John Shook PRODUCTION CONTROL 2 shifts 18,400 pieces/mo 12,000 “L” 6,400 “R” Tray = 20 pieces 90/60/30 day Forecasts Daily Order 6week Forecasts Weekly fax Daily (Milk Run) 1 x daily Daily Order O X O X WELD + ASSY Takt = 60 seconds 2 shifts C/O = 0 Uptime = 100% total work content = 168 seconds SHIPPING Staging Completed FutureState Map State Street Assembly STAMPING EPE = 1 shift 27,600 sec. avail. C/O 10 minutes Uptime = 85% Production Lead Time = days ValueAdded Time = 169 seconds days 1 sec 1 day 168 sec 2 days Changeover Coils (at the press) Michigan Steel Co. tote coil coil batch L R 20 20 20 40 CORE TIME ANALYSIS days days 169 seconds days Currentstate Production Lead Time (Actual Time) Futurestate Valueadded Time (Core Time) Futurestate Production Lead Time (Target Time) 188 seconds Currentstate Valueadded Time The core time is the absolute minimum (valueadded) time to carry out a production task. A reasonable amount of time has to be added back as allowance for a realistic amount of waste (batching, transportation, etc.). Futurestate Allowance (Accepted Extra Time)