One of the more challenging industries to get lean is the mixed model, made to order, assembly production lines. We all have read the success in high volume production lines with options but what if you are producing several distinctly different products on the same line. It becomes a challenge as each station needs to be level loaded for the processing time so the overall cycle time remains consistent. There are several pieces of ground work that must be accomplished prior to any indoctrination of lean processing. While this may seem like a huge task that will take significant time to complete, the manager must remember the basic elements of success – a vision and a strategic plan that states which product line is approached first. Your vision should state what the perfect production line would resemble and the plan will state the cadence of products and the sub-steps to completion. You must remember that cellular or assembly processing must call for the same processes to be followed each time a product is produced. Repetition makes it easier to control quality and also allows you to track whether improvements have a positive or negative effect.
1. Value stream map each assembly
2. Create sub assembly operations and co-locate them to the line in a balanced process and cycle time
3. Break out and balance the tasks
4. Layout inventory, tools, workbenches so that tasks can be eventually and linearly be produced
5. Create inventory feeder line strategies and kits for common sub-assembly operations
6. Define and set in place Standard WIP
7. Create standard work
8. Determine the proper spacing in the flow. Make every a incorporate a “U” shaped cell (Rabbit Chase)
9. Cross train operators
10. Create standard work for the “load versus operators” necessary to meet Takt time
11. Determine the vortex operations and assure that all operators are trained in these operations
12. Assure that there is contingency planning for excess load and equipment failures
While these are not the only elements that must be addressed they are the basics for your journey’s inception. Do yourself a favor and benchmark other and similar industries. Most manufacturing facilities are eager to share their successes and you will not be re-inventing your entire operation as you can use the “Best in Class” practices. You must remember that this is not easy and you will never be complete in your leaning of the lines. After each iteration, you will discover new avenues for improvement.