Precision Aerospace Machining and the Seven Wastes of Lean Manufacturing (part 6)

The sixth waste that we will examine is that of over-processing.  The definition of over-processing is to do more work on a piece than is required by the customer.  In the simplest explanation this is simply anything done to the part that does not add value to the product.  A good – and controversial – example of over-processing a part is inspection.

Pretty much everyone would agree (I assume) that inspection is a necessary part of the process of precision manufacturing.  When it comes to precision aerospace parts, it is difficult to imagine shipping parts without a full detailed inspection.  The consequence of a defective part could be catastrophic – so we inspect everything.  However in the process of inspection, assuming that the part is manufactured properly and passes inspection, nothing is done to increase the value to the customer.  The part is exactly the same after inspection as it was before.

There are many other ways to over-process a precision machined part.  Using tools that are more expensive than necessary, running machines too slow, over-engineering the fixtures, holding a tolerance beyond what is necessary for function, or a number of other problems.  Of all of the wastes, I think that over-processing may be the most difficult to eliminate, or even identify at times.

The approach that we take at CNC Industries to eliminate over-processing starts before we run the first part of the first batch that we produce.  Before any new part is produced, we conduct a ‘pre-flight meeting’ in which we examine all aspects of the part.  We will look into all of the common areas of over-processing and ensure that steps are taken to prevent over-processing.  Once a consensus process is established and reviewed to ensure that it will be ‘lean’ enough, we enter the router information into Job Manager 2, our ERP system.  At this time the process established will be on record for each involved party – from purchasing to final shipping, all processes have been reviewed to eliminate over-processing, as well as the other wastes.

With our electronic information system we are able to continually review the established processes quickly and thoroughly.  Every employee in the company is also able to suggest improvements – which has many times lead to a reduction of waste – often through elimination of over-processing.  With over-processing waste it is critical to constantly be looking for a better way to produce the parts.  The effects of over-processing can be very expensive, but it is often hard to detect.

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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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June 25th, 2010|