绘制价值流图常见问题(英文版)

1、Value Stream Mapping Train-the-TrainerInformation For A Process Data Box(to be collected on the shop floor) Cycle time Changeover time Process reliability (uptime) Scrap/Rework/Defect rate Number of product variations Number of operators Production batch sizes Working time (minus breaks) Pack size T

2、ypical Steps to Complete a Current State Drawing Document customer information Complete a quick walk through to identify the main processes (i.e., how many process boxes) Fill in data boxes, draw inventory triangles, and count inventory Document supplier information Establish information flow: how d

3、oes each process know what to make next? Identify where material is being pushed Quantify production leadtime vs. processing time Many shops have a combination of repetitive and non-repetitive products (indicating product families) Product families might be difficult to see focus on machines/operati

4、ons and work content time Engineering might be included in the information flow for leadtime impact, etc. Pitch is typically arbitrary to the manager Employment of pitch requires detailed knowledge of work content and routings for jobsFrequently Asked Questions: Make to Order and Engineer to Order S

5、hopsFAQ: Distribution Centers ExampleRECEIVESTOCKPICKPACKSHIP(Information flow on top)IIIIIFAQ: Parallel Manufacturing Flows Keep it simple, and make sure to leave room for the data boxes!FAQ: Including Subassemblies Focus on major subassemblies first Select one or two which might represent differen

6、t types of situationsGeneric vs. specific to the product familyOutsourced tasks within assembly Follow the format for parallel flow, and always include the main assembly process! For large fabricating and assembly operations, consider maps for each major subassembly with a “macro map” indicating the

7、 entire product family FAQ: Do We Really Have a Supermarket (or FIFO lane)? Supermarkets (and FIFO lanes) control production between points of flow without a written schedule.What is the trigger for production in this area of the value stream?Is the upstream process overproducing? If there is a sche

8、duling system present outside of a pure pull, chances are that there is no supermarket.FAQ: OutsourcingXYZCorporationI300 piecesMon+ WedI100 piecesMon+ WedC/T = 1 hourL/T = 3 daysBatch = Min. Batch = 3 Days60 min.2 days.7 daysFAQ: Long Processing Times vs. Production LeadtimesI300 piecesI100 piecesC

9、/T = 8 hoursC/O = 25 min.Rel. = 100% Batch = 100 pcs. 8 hours8 hours3 days1 dayCUREFAQ: Cycle Times vs. Work Content Work content is important to understand costs and in balancing flow Consider all machine and manual work content, regardless of the cycle time Accumulate all parallel operations in th

10、e processing timelineC/T = 30 sec.C/O = 25 min.ASSEMBLY= 5Cycle Time = 30 secWork Content 150 sec.FAQ: Different Changeover & Cycle Times, etc. Current state mapping might uncover:Several different machines performing the same operationDifferent products within the family with different data box

11、 characteristics for a specific process Capture the range of values as opposed to an average valueFAQ: Mapping Final Inspection/ Repair/Rework Judgment counts! Minimal repair/rework might be captured as a data attribute at the final step. If nearly every part needs assessment or extra work, consider

12、 a separate process box. FAQ: Supplier Data Boxes Data attributes are dependent on the value stream and supplier. Minimum information might include:XYZSupplierL/T = 3 weeksBatch = 3 TonsMin. Batch = 2T2% ScrapFAQ: Pull Within an MRP Environment A combination push and pull is usually just a push syst

13、em! Multiple production triggers typically lead to overproduction.FAQ: Assemble-to-Order Options in a Future State Finished goods supermarkets can be expensive in value streams which have many finished part numbers within a product family To minimize inventory costs, try to find the upstream locatio

14、n where the value stream has very few variations and consider a supermarket of WIP at that point. Customers orders can “drop” to this location, with FIFO lanes controlling production into shipping.FAQ: Assemble-to-Order Options in a Future StateCUTF I F Omax 20 piecesASSEMBLESHIPF I F Omax 20 pieces

15、Customer OrdersOXOXFAQ: Why Not Just Start Pulling Tomorrow? Initiating a pull system without first attempting to flow will result in lots of supermarkets, and may increase your inventory levels. Design your future state with the following sequence:Flow wherever you can (while still pushing)Produce

16、to the TAKT (while still pushing)Implement a pull system FAQ: Administrative Mapping: Part 1: Integrated Include functions such as engineering, purchasing, and order entry for product families which have routine activities prior to scheduling Place the process boxes between the customer and the scheduling function Minimize the data collection to the basics of cycle time or quality, and document the impact on leadtime FAQ: Administrative Mapping: Part 2: Separate Maps Better for redesigning overhead and administrative support are