Lean manufacturing and Aerospace Machining, Low Volume / High Mix production

Lean manufacturing is a concept that most businesses strive for and many claim.  The primary concept of lean manufacturing is eliminating all unnecessary costs and time associated with production.  The primary way most companies will start with Lean is to manufacture parts as fast as possible – to get as much production from each machine as possible.  As the cycle time decreases wasted machine time decreases as well.  This is a great start to lean manufacturing, but it is also the most common method.  Many companies focus on cycle time reduction almost entirely in their lean efforts.

Cycle Time reduction works best in environments where a machine shop is producing the same part for a long duration.  This is typically a full production shop and will have dedicated machinery to optimize a single process to the fullest extent possible.  In the aerospace machining industry or custom machined parts production we are not producing high enough volumes of many parts to dedicate an entire machine to a single part.  As such aerospace machine shops and custom manufacturing shops (or job shops) will face additional difficulties in going ‘lean’.

Adjusting the cycle time down by 10% is not as effective of a lean tool when machine time may only be 60% or less of the time spent on producing a given part.  The lower the proportion of machine time to non-machine time in a job, the more important it is to go lean in additional ways.  in connection to that – the more often a machine needs to be set up for a new job the more non-machine cost is in the job – for reference a single aerospace machined part may have 5 or 6 separate  machining operations each requiring an additional setup on the machine.  Transferring the material to different areas, setting up the machine, inspecting the part throughout production, and other items add to the non-machine time at every step.

Over the next few posts I will be looking at the 7 wastes identified in a typical lean manufacturing implementation and how CNC Industries deals with each on in relation to our low volume / high mix work.  We have some production jobs as well, but those are handled in slightly different ways, and will be discussed at a later time.

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CNC Industries is a Fort Wayne, Indiana based machine shop specializing in precision CNC machining, fabrication and assembly of application-critical and custom machined parts for the Aerospace, Defense, Medical, Industrial and Transportation  markets.   The company presently employs approximately 55 people.

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