Rework by Inspectors - Pros and cons of a quality inspector also doing rework?

[RosieA]

Need opinions:

What are the pros and cons of having a quality inspector also do the rework on defects he/she finds?

My concern is that by having the inspector fix the problem, the process step where the problem occurred doesn't get investigated.

I've suggested operator self-inspection before it moves to the in-process inspection (Rockwell harness Test), but was initially rebuffed. I was told it would be too time consuming for the operator to do.

Opinions?

 

[Michaelar]

quality inspection / rework

Need opinions:

What are the pros and cons of having a quality inspector also do the rework on defects he/she finds?

My concern is that by having the inspector fix the problem, the process step where the problem occurred doesn't get investigated.

I've suggested operator self-inspection before it moves to the in-process inspection (Rockwell harness Test), but was initially rebuffed. I was told it would be too time consuming for the operator to do.

Opinions?

My number concern would be the rework. what are we talking about here, adding a missing clip / bumper or are we talking about removing weld spatter. Would the quality inspector be trained on the rework? how difficult is the rework and what damage could be done by someone inexsperienced?
My second concern would be ,how much time will the rework take away from the actual inspection? would it be more profitable to add another person into the process just to rework? Have you thought about a 3rd party inspection/rework?
then you are looking at how is this recorded. will someone fudge the numbers. how are you making the inspected parts verses the reworked parts?
traceability of the part. how many hands did this part travel thru?

 

[RosieA]

The rework is to straighten the part, which is required on close to 50% of all parts that hit the hardness inspection step. Inspection time is definitely impacted, but the other concern is who inspects the inspector? The answer is, no one.

 

[Wes Bucey]

I've often considered the issue of rework, whether it should be done, who should do it, how it should be reinspected, etc.

In my experiences with this issue, the prime driver was budget.
The facets (which all affect budget) I most often considered were:

• the time and labor to identify nonconformance and determine whether it CAN be reworked within terms of any customer requirements to be conforming
• the time and materials to do the rework
• whether the time and materials could more profitably be expended in making NEW pieces (or in doing any other work in the enterprise)
• the cost of a redundant reinspection (whether to just reinspect for the repaired feature or to reinspect the entire piece because of possibility of damage during the repair process)
• notification to and concurrence from customer for reworked pieces
  (State Farm just agreed to $40 million settlement for not informing customers about reworked autos)
• whether reworked pieces should be identified and segregated from original production
• concurrent efforts to trace root cause of nonconformance and to create and implement corrective and preventive processes

In my opinion, there is no single "right" answer to the question in any company or for any given piece part.

note I haven't even addressed training, competence, or integrity of inspector to perform rework and reinspect the product - they all come AFTER the budget factor in my mind.

 

[wmarhel]

I've suggested operator self-inspection before it moves to the in-process inspection (Rockwell harness Test), but was initially rebuffed. I was told it would be too time consuming for the operator to do.
Opinions?

What's the possibility of determining and eliminating the root cause of the problem?

With the exception of some regulatory, contractual, or liability issues; what is the need for inspection? I would push the product back on the department producing the garbage and offer assistance to correct the problem, but that's a battle you'll have to determine whether you can win or not.

Has anyone done a study of the process to determine whether it would negatively affect the operator. I just ran into a similar problem where the plant mgr, and supervisor claimed that the data collection was costing them over an hour of production time during an eight hour shift. The sad thing, was that the numbers only showed about a 15 minute loss per shift. Needless to say, it didn't have anything to do with facts, and everything to do with trying to keep their little empire secure so we continued with the data collection.

Do it once and its a favor, do it twice and it is now "your" job.

Wayne

 

[RosieA]

Do it once and its a favor, do it twice and it is now "your" job.

Wayne

Oh so true!

The Rockwell hardness test has to be done to determine if the heat treat process did what it was supposed to do. I've only been on the job for 7 weeks, I'm not sure what the roots of the straightness issue are, but your suggestion to do a process study is a good one.

My early perception is that this product group is pretty hard to work with, and data will help validate the perception that operators don't have time to self-inspect their work.

 

[Kevin H]

re: Rework by Inspectors

Rosie, I can share the concerns raised by the other posters. As a metallurgist, I also have another issue - depending on the part, straightening could have an impact on the Rockwell hardness test. Hard to second guess from an internet forum - not knowing the exact preceding part, the straightening operation, etc., but experience from years ago when I was a heat treat metallurgist showed that mechanical working, such as straightening heat treated or annealed bar prduct increased Brinnel hardness by 1 or more readings. The equivalent would be going from 32 Rc to 33 Rc for the heat treated product. For the annealed we were down around the equivalent of 92 Rb and would see an increase of 1 or 2 points Rb.

Don't know if that concern would apply to your operation, but if it did, you'd probably end up with 100 % reinspection for hardness of straightened parts. Might be a whole lot less expensive corporate wide to determine a root cause and correct it as mentioned by wmarhel.

 

[Claes Gefvenberg]

What are the pros and cons of having a quality inspector also do the rework on defects he/she finds?

I share your concern about the process step where the problem occurred not getting investigated. Another thing: Your inspector may have great integrity, but having to correct them, he is in a way getting punished for finding faulty items.

I've suggested operator self-inspection before it moves to the in-process inspection (Rockwell harness Test), but was initially rebuffed. I was told it would be too time consuming for the operator to do.

Really? Why would it be less time consuming to move the parts to an inspector before checking them?

how many hands did this part travel thru?

Exactly. That will not make it any better...

The rework is to straighten the part, which is required on close to 50% of all parts that hit the hardness inspection step.

50%??? :mg: What about the process? Bring in the designers and production engineers. I know what heat treatment can do to the shape of parts, but if that part of the process cannot be improved, events seem to indicate that straightening should be a normal part of it.

Do it once and its a favor, do it twice and it is now "your" job.

Indeed... Do that and you own the problem.

/Claes

 

[Caster]

Let's make a deal

I just ran into a similar problem where the plant mgr, and supervisor claimed that the data collection was costing them over an hour of production time during an eight hour shift. The sad thing, was that the numbers only showed about a 15 minute loss per shift. Needless to say, it didn't have anything to do with facts, and everything to do with trying to keep their little empire secure so we continued with the data collection.Wayne

Wayne

I laughed at this. Heard the exact same comment years ago. Foreman said SPC was killing production, they couldn't make parts because of all the stupid paperwork Quality wanted.

So I told him in a production meeting (why is it always a him) to stop all the paperwork immediately. He was happy. Then I asked how many more parts he was going to give us a shift. Only then did he see the trap I'd set. Won the battle but lost the war on that one, SPC died soon after.

Claes is correct, it takes a Saint to call out bad product if she has to then fix it. Especially when the person who made it bad is just going to keep doing it.

Perhaps cost of quality analysis could help here, 50% rework should easily justify heavy investment in improvement. The hidden costs are huge.

Good luck!

 

[Sam]

The rework is to straighten the part, which is required on close to 50% of all parts that hit the hardness inspection step. Inspection time is definitely impacted, but the other concern is who inspects the inspector? The answer is, no one.

I see nothing wrong with this method. This appears to me to just be another step in the process. If 50% of the parts need to be straightened, then I will assume you are doing 100% inspection.
Is this a final step before shipping to the customer or is there another operation that will validate the straighteness of the part?
If it is a final step then, yes you would need some form of product audit to satisfy quality system requirements. If no, then the next operator becomes the inspector.