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Value Stream Mapping. How to Create the Future State. Issue: You have mapped a current state, so what should your ideal or future state map look like? Overproduction – eliminate overproduction, or attempt to level production.
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Value Stream Mapping How to Create the Future State Issue: You have mapped a current state, so what should your ideal or future state map look like? Overproduction – eliminate overproduction, or attempt to level production. Source – “Learning to see, value stream mapping to create value and eliminate muda”, by Mike Rother and John Shook
Value Stream Mapping • Guideline #1: Produce to your takt time. • Takt time = available working time per day • customer demand rate per day • Example: 27,600 sec = 30 seconds • 920 parts • Caution - if processes are set to the takt time, then efforts must be made to: • Provide fast response (within takt time) to problems • Eliminate causes of unplanned downtime • Eliminate changeover time in downstream, assembly-type processes Characteristics of a Lean Value Stream
Value Stream Mapping Guideline #2: Develop continuous flow wherever possible. Producing one unit at a time, continuously passing from one process step to the next without stagnation. Be very cautious when implementing – continuous flow only works when all processes are completely reliable, changeover times are reduced to near 0, and smaller, in-line equipment are developed or available. Start by implementing several shorter continuous flow areas with small buffers in-between. As downtime and changeovers reduce, start increasing the length. Characteristics of a Lean Value Stream
Value Stream Mapping Guideline #3: Use supermarkets to control production where continuous flow does not extend upstream. Supermarket is a short-term storage place where continuous flow is not possible, due to batch processing requirements of upstream operations. The downstream operation pulls parts from the supermarket when needed. The upstream operations’ job is to keep the supermarket filled, no additional scheduling of the upstream operation is required. Caution: how many of each part should the supermarket hold? Characteristics of a Lean Value Stream
Value Stream Mapping Guideline #3: Use supermarkets to control production where continuous flow does not extend upstream. Example of use of Kanbans in a supermarket. Insert page 46 figure Characteristics of a Lean Value Stream
Value Stream Mapping Guideline #4: Try to send the customer schedule to only one production process. The ideal point to schedule is at the process at the beginning of the continuous flow (pacemaker process). Upstream operations will be scheduled via “supermarkets”. Insert page 49 picture Characteristics of a Lean Value Stream
Value Stream Mapping Guideline #5: Distribute the production of different products evenly over time at the pacemaker process (level the production mix). Leveling production mix is viewed as alternating repeatedly between all product types in the assembly area. This could be accomplished by adding slower/shorter assembly lines, or by reducing changeover time, or other… The payback is increased responsiveness to customers, shorter lead times, smaller finished goods inventory, and smaller upstream supermarkets. Characteristics of a Lean Value Stream
Value Stream Mapping Guideline #6: Create an “initial pull” by releasing and withdrawing small, consistent increments of work at the pacemaker process. (Level the production volume). The idea is to continuously be releasing production orders to the shop floor. The small increments (or pitch) allows you to also quickly and accurately assess how you are performing. A heijunka box is often used, this box consists of an array of columns and rows. Each row represents a product type, and each column represents a pitch interval. Characteristics of a Lean Value Stream
Value Stream Mapping Guideline #6: A heijunka box is often used, this box consists of an array of columns and rows. Each row represents a product type, and each column represents a pitch interval. Insert pg 53 Characteristics of a Lean Value Stream
Value Stream Mapping Guideline #7: Develop the ability to make “every part every day” (then every shift, then every hour or pallet or pitch) in fabrication processes upstream of the pacemaker process. Characteristics of a Lean Value Stream
