What is the Difference between Rework v Repair?

There is much discussion and confusion regarding the difference between rework and repair in a manufacturing environment. This is due to so many industry specifications.


These specifications are rarely written in simple English and are full of jargon and legalese. I’ve Googled this subject and found an enormous array of answers. From my experience the difference between rework v repairs is much simpler than anything I’ve read online. Naturally you must research your particular situation when in doubt simply ask auditors.

Let me share my simple definition of rework v repair.

Rework – Bringing a non-conforming part back into conformance by simply reprocessing a prior sequence.

Repair – Bringing a non-conforming part back into conformance using methods outside the original process.

Simple Router

10. Pull widget blank from stock.

15. Drill   .015 – .020 diameter lock ring hole using G9746 press.

20. Clean

25. In process inspect

30. Heat Treat (Harden)

35. Final Inspect

40. Stock

Let’s review two scenarios of non-conformance.

Rework Example

Drilled hole found to be .005 undersized at sequence 25 the in process inspection. Engineer determined worn or wrong size drill was the root cause. The rework simply involves changing drill bit and reprocessing sequence 15 and continue router from that point.

This is considered rework because you simply redoing a process correctly.

Repair Example

Drilled hole found to be .005 undersized at sequence 35 final inspection. Engineer again determined worn or wrong size drill was the root cause. However this time the part was found in a hardened state. Engineer must repair by adding sequence not on the original router.

Before reprocessing sequence 25 the Engineer must soften material using the thermal process called annealing.

Because there was a new process introduced it would be considered a repair.

This simple explanation will fit the machining process the best. Each industry and situation has its own nuanced definition of rework v repair so be sure to know yours. Use my definition as a talking point to begin the conversation.

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6 Responses to What is the Difference between Rework v Repair?

  1. Hi David

    I would have to agree with you rework should always be just repeating the original process to get it fixed; while repair is using a different process to get to the same final finished product. Will accountants doing an audit agree, who really knows, I sure couldn’t tell you (after all I have a degree in accounting and the thing I realized was that some accounting concepts really do not make sense).

    • David - LeanPlanet.org says:

      When it comes to manufacturing, audits typically focus more on product reliability issues than accounting. Accountants are primarily concerned with cost variances. The usual battleground in companies seeking lean solutions is the issue of cost avoidance. For instance if a product cost $500.00 to replace but the engineer can repair for $300. Is the repair a $300 cost or a $200 savings in cost avoidance, or possibly both? How your company treats these type costs will affect the behaviors the engineering staff. This is the reason lean accounting is so important you always want your policies to drive proper behaviors not conflict with them.

  2. Luis Suarez says:

    I understand that repair is about re-establishing a product functionality but the product may remain non-conformant is certain aspects. For instance: touching-up the exterior finish (e.g. paint), the protection aspect of the function is re-established but the product may not be conformant to the respective qualitative quality specification.

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  4. What is the difference between Deviation and Concession , with Example

    • David - LeanPlanet.org says:

      A deviation in the context your inquiring (I believe) is a value outside of accepted tolerances. A concession is allowing that deviation because it doesn’t violate fit, form or function of product. Also there are many times when the deviation is from a primary operation but later finish operations will bring it into the correct final specifications. This is the reason designers shoot for MMC (Maximum Material Condition) at primary machining operations.

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