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Jeff Liker

Jeff Liker: Don’t confuse JIT shipping with a JIT system

By Jeff Liker, - Last updated: Monday, September 24, 2012 - Save & Share - Leave a comment

We did work for a JIT seat assembly plant that shipped in sequence to automotive.  They were proud of the plant for being “lean.”  After all it shipped JIT.  Walking through the plant it was obvious it was far from lean.   Yes they had an assembly line for the seats and yes they shipped in the exact sequence of the auto assembly lines.  But in reality they were sequencing out of a large inventory in an automated storage and retrieval system, the standardized work and training on the assembly line were awful, the line was not well balanced, built-in quality was mostly absent, and there was a mountain of inventory of incoming materials surrounding the assembly line (e.g., foam, seat covers, frames).  They were confusing JIT shipping with a JIT system.

Having said that the upstream processes like building the frame were even worse.  In the case of a mass production press shop there are various problems to attack depending on how automated the technology is.  If it is not automated then there is plenty to do on the jobs of loading and unloading.  Certainly SMED is critical for the main purpose of reducing lot size.  From an overall flow viewpoint in Learning to See the Acme Stamping case is very much like your situation.  The current state is common–scheduling individual processes, building huge batches of stamped parts, large amounts of inventory incoming, WIP, and finished goods, no real standardized work, unbalanced work loads, and no real heijunka.  The Acme future state is a good starting point for your future state though every situation is different so be cautious in copying.  But the flow issue starts with heijunka which starts with the JIT assembly line.  If the assembly line is building to a real takt and is leveled that will level the pull on the press shop.  Then simple kanban systems can be very effective.  As you reduce changeover time on the presses you can build smaller lots which develops a rhythm between press and assembly.  Then having stabilized press and assembly you can work with your suppliers to move toward JIT delivery where possible.   If this is all done then you can move to the second cycle of fine tuning all these processes which is a never ending journey of continuous improvement.

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