精益概论 ASME Lean Overview.

1、 Lean Manufacturing Overview Objective : Doing more with less Becoming LEAN means . Elimination of anything not absolutely required to deliver a quality product on time for the customer SUPPLIERFACTORY FINAL ASSY FAB SELLING ENTITY CUSTOMERWAREHOUSE Lean Operation: looks at the entire stream Lean is

2、 a systematic approach to identifying and eliminating waste through continuous Tools and key/common terms: Value stream mapping Push vs. pull Kanban Muda elimination VA vs. NVA Set up time reduction One-piece flow Operator cycle time Spaghetti diagram Standard work Layout analysis Visual controls Li

3、ne balancing Kaikaku / Kaizen Poka-yoke Takt time TPS Etc., etc. etc. improvement by flowing the product at the pull of the customer in pursuit of perfection Characteristics of a Lean Operation Processes are in place to capture the knowledge of customers (internal and external!) and their values Ali

4、gned, efficient processes provide quality products to the right customers at the right time The entire product delivery process is flexible so the enterprise can respond quickly to changes Management of systems, processes, and people is based on metrics and is aligned at all levels to evaluate perfo

5、rmance All processes, systems, and initiatives are aligned, including supplier partnership Benefits/Goals of Lean Manufacturing Best Quality Lowest Cost Shortest Lead Time Best Safety 1.High (Employee) Morale Lean manufacturing shortens production flow by eliminating waste to achieve: Lean and your

6、company Which one of the five goals is your company most interested in? Which of the five do you think would be the biggest competitive advantage to your company? As a mechanical engineer, which of the five do you think YOU could have the greatest impact on? Lean manufacturing was developed at the T

7、oyota Motor Company of Japan The term “lean manufacturing” came years later, from author James P. Womack. Toyota got some of its ideas for TPS from Henry Ford: Shortened production flow physically locate each process on the shop floor adjacent to the process that came before it. Standardized work st

8、andardize the parts, discover the most efficient way produce then standardize the production work. Reduced cycle times Eliminate unnecessary movement required by workers (e.g., placed tools/parts in easy reach). and originally called TPS “Toyota Production System” As the customer buys an item, make

9、another to replace it Taiichi Ohno, Eiji Toyodas production genius, originated the concept of just-in-time manufacturing. In the supermarket he saw an incredibly efficient consumer-driven supply chain. Daily and weekly orders to suppliers made it possible to eliminate warehousing by the grocery stor

10、e no storage costs, no overproduction. this is the heart of the pull system or JIT manufacturing Taiichi Ohno expanded “just-in-time” manufacturing into the factory No part is made upstream in the manufacturing process until it was “pulled” (required) by a process downstream. This avoided overproduc

11、tion (the worst kind of waste). Parts “flow” through the plant at a level pace, no batches lined up waiting for the next process. If parts stack up between processes (buffer or safety stock), it interrupts the continuous flow of manufacturing that is critical to the lean manufacturing process. Produ

12、cts that flow continuously through the production process are created much more efficiently than those that start and stop, piling up at various points in the “batch and queue” system of “push” manufacturing. which creates continuous flow in the process The inefficiency of large inventories from Lea

13、n Thinking It takes about 3 hours of actual processing time to transform the ore in the mine into the soda can in your hand. However, when one adds the time it is stored on the way in and out of the reduction mill, smelter, hot rolling mill, cold rolling mill, can maker, bottler, and grocery chain,

14、the process to get the ore formed into the can is stretched into 319 days. There are huge opportunities for a just-in-time system for: Finished product inventories Work-in-progress (WIP) inventories 3. Quantity (and pace) of production is determined by customer demand Pull system mix and match “corr

15、ect or switch” Requires less frequent ordering of raw Product design is not driven solely by Parts and products are made over a short Uses time and resources efficiently. Requires no buffer stock. Products are created using a Quantity (and pace) of production is Reduces costs by reducing inventory.

16、“ Just-in-case” (Push system) Just-in-time (Pull system) C/S Requires less frequent ordering of raw materials and parts 9. Requires more frequent ordering of raw materials and parts Product design is not driven solely by customer requirements 8. Product design is driven by customer Requirements, i.e

17、., value Parts and products are made over a short period of time 7. Parts and products are made over a long Period of time Uses time and resources efficiently. 6. Uses time and resources inefficiently. Requires no buffer stock. 5. Requires buffer stock. Products are created using a batch and queue s

18、ystem 4. Products are created using a continuous Flow system Quantity (and pace) of production is determined by forecasting Reduces costs by reducing inventory. 2. Creates large stock of inventory. Traditional method used by many U.S. companies (and even many Japanese companies) 1. Innovative method

19、 used by Toyota Motor Company and other lean operations “ Just-in-case” (Push system) Just-in-time (Pull system) C/S C S C C S S S C C The essence of TPS “The key to the Toyota Way and what makes Toyota stand out is not any of the individual elements But what is important is having all the elements

20、together as a system. It must be practiced every day in a very consistent manner not in spurts.” - Fujio Cho, President of Toyota Motor Company (Liker, The Toyota Way, 2003 Only as strong as the weakest link Lean manufacturing requires rethinking the way work is done coordinating everyone and everyt

21、hing to shorten production flow by eliminating waste. It requires looking at the total process, the “value-stream” from raw materials to finished product, as well as order entry to shipping. Finally, one must apply lean principles to the “extended value stream”, the companys partners, suppliers, shi

22、ppers, and distributors. 2 X Week 2 X Week 2 X Week S employee frustration increases, morale decreases. Time to market it not optimized, providing little or no “value” to the customer. If the entire manufacturing process time is reduced from 7 weeks to 3 days but it still takes order processing 2 we

23、eks to complete the paperwork for each order then Customers still wait eleven days longer than necessary and needless inventory costs continue. If the entire organization can respond to fluctuating customer demand on a 3 day cycle but the raw materials supplier requires bulk orders once a month then

24、 The factory must order and stock more inventory than they need. Waste Identification Waste is “Anything that adds Cost to the product without adding Value There are many examples of waste in the workplace, but not all waste is obvious. It often appears in the guise of useful work. We must see benea

25、th the surface and grasp the essence. Adding Value Is this activity something that the customer is willing to pay for? Does this activity change the fit, form or function of the product or service? Lean Manufacturing - Four Step Focus Step One - Understand what waste is Step Two - Identify where was

26、te is in the process Step Three - Use appropriate waste elimination tool to eliminate specific waste identified Step Four - Aggressive implementation of plans. Do it now! Types of Waste DEFECTS Repair or Rework MOTION Any wasted motion to pick up parts or stack parts. Also wasted walking TRANSPORT W

27、asted effort to transport materials, parts, or finished goods into or out of storage, or between processes. OVERPRODUCTION Producing more than is needed before it is needed INVENTORY Maintaining excess inventory of raw matls, parts in process, or finished goods. PROCESSING Doing more work than is ne

28、cessary WAITING Any non-work time waiting for tools, supplies, parts, etc. Overproduction is considered the greatest waste because it generates so many of the other wastes The 7 wastes are at the root of all unprofitable activity within your organization. The acronym “DOTWIMP” is used to remember th

29、e 7 wastes: Its not always black and white Value Added Necessary Value Added Not Necessary Non Value Added Necessary Non Value Added Not Necessary Drilling, machining, turning, cutting, forming, heat treat, cure, shear, bend Inspection, pilot holes, part mark, order release, inspection buy offs, cle

30、an, deburr Operations called out but no longer needed, (questionable whether or not VA) Counting, moving long set-ups, additional inspection steps, additional paperwork, interim stock locations, packaging and un- packaging Value Added Necessary Value Added Not Necessary Non Value Added Necessary Non

31、 Value Added Not Necessary Drilling, machining, turning, cutting, forming, heat treat, cure, shear, bend Inspection, pilot holes, part mark, order release, inspection buy offs, clean, deburr Operations called out but no longer needed, (questionable whether or not VA) Counting, moving long set-ups, a

32、dditional inspection steps, additional paperwork, interim stock locations, packaging and un- packaging Time is the Shadow of Motion Waste What value is Added by: What value is Added by: Sorting Counting Acknowledgments Moving Expediting Inspecting Returns to Suppliers Repackaging Scrap Storing Invoi

33、ces Rework Loading / Unloading Receiving Report JIT - A Strategy Based on Lead Time JIT - A Toolset For Eliminating Waste Example: Lead Time Reduction CAR DEALER A CALL, MAKE APPOINTMENT TAKE CAR IN WRITE UP ORDER WAIT FOR SHUTTLE CALL: SEE IF CAR IS DONE GET RIDE BACK TO DEALER CHECK WITH SERVICE P

34、AY CASHIER LOOK FOR YOUR CAR CHECK OIL DRIVE OFF TRADITIONAL 8 HOURS PENNZOIL 10 MINUTE OIL CHANGE CAR DEALER A CALL, MAKE APPOINTMENT TAKE CAR IN WRITE UP ORDER WAIT FOR SHUTTLE CALL: SEE IF CAR IS DONE GET RIDE BACK TO DEALER CHECK WITH SERVICE PAY CASHIER LOOK FOR YOUR CAR CHECK OIL DRIVE OFF TRA

35、DITIONAL 8 HOURS PENNZOIL 10 MINUTE OIL CHANGE QUICK LUBE DRIVE INTO LUBE AREA WRITE UP & PAY WHILE OIL IS BEING CHANGED PAY CASHIER DRIVE OFF DEAL 10 MINUTES QUICK LUBE DRIVE INTO LUBE AREA WRITE UP & PAY WHILE OIL IS BEING CHANGED PAY CASHIER DRIVE OFF DEAL 10 MINUTES CAR DEALER B DRIVE INTO LUBE

36、AREA WRITE UP ORDER PAY CASHIER WAIT PICK UP CAR DRIVE OFF IMPROVED 29 MINUTES CAR DEALER B DRIVE INTO LUBE AREA WRITE UP ORDER PAY CASHIER WAIT PICK UP CAR DRIVE OFF IMPROVED 29 MINUTES PENNZOIL 10 MINUTE OIL CHANGE Waste who wants what Your Company Profit Repeat Business Growth Your Company Profit

37、 Repeat Business Growth Cash ! Cash ! $Cash ! Cash ! $ Customer Low Cost High Quality Availability Customer Low Cost High Quality Availability Value ! Value ! Value ! Value ! What would you prefer Price Increase Bigger Profit Bigger Profit Some Profit Some Profit Price to Sell Cost to Produce 1 2 3

38、1 Some Profit Some Profit Price to Sell Cost to Produce 1 2 3 Some Profit Some Profit Price to Sell Cost to Produce 1 2 3 1 1 2 2 3 3 1 1 2 2 3 3 Cost + Profit = Price Cost + Profit = Price if you are the customer? Lean is a continuous journey Management Commitment 1 2 3 4 5 6 7 Lean Operation Ident

39、ify The Value Stream Process Mapping Gap Analysis Elimination of Waste Set Up Reduction, 5 S, Takt Improve Value Stream Flow Kaikaku, Visual Management Improve Stream Quality TQM, Poka Yoke Pull System Kanban,. JIT, P.O.U. Continuous Improvement Training & Awareness Management Commitment 1 2 3 4 5 6

40、 7 7 Steps to a Lean Operations Lean Operation Identify The Value Stream Process Mapping Gap Analysis Elimination of Waste Set Up Reduction, 5 S, Takt Improve Value Stream Flow Kaikaku, Visual Management Improve Stream Quality TQM, Poka Yoke Pull System Kanban,. JIT, P.O.U. Continuous Improvement Training & Awareness Management Commitment 1 2 3 4 5 6 7 Lean Operation Identify The Value Stream Process Mapping Gap Analysis Elimination of Waste Set Up Reduction, 5 S,