The situation in our company is like this:
Customer gives us a lot of drawings. We forward the drawings to our suppliers and tell them to make parts according to the drawings. Suppliers agree.

The problem is: every time the parts sent by the suppliers have a large proportion (60% ~100%) that exceeds the tolerance limit. We accept them as concession each time because we conclude the suppliers don’t have the capability to meet the specification requirements. Besides, the parts, although exceeding tolerance limit, fit the assembly quite well. The customer, knowing the parts exceed tolerance limit, accept the finished product each time as concession.

Because it is common knowledge that we can not use the specification on the drawing to decide the acceptability of the incoming parts, each time we let QC inspectors do a preliminary inspection according to the drawing, then write a Discrepancy Report, then we let Quality Engineers do a second inspection on the defectives found, and make a judgment whether they can be used or not according to their manufacturability.

This process, of course, is wasteful, so I proposed to the quality manager that we should make incoming material inspection instructions for each part (currently they don’t exist), and the acceptance criteria on the inspection instruction should be slightly looser than the one provided by the customer’s drawing, so that the incoming parts can at least meet the tolerance requirements on our inspection instruction, although may not meet the tolerance requirements on the customer’s drawing.

My supervisor strongly opposes this idea, insisting that we can not change any customer specification. I argue that we do not change customer specification; we just change our specification, to make it closer to our actual capability. My supervisor disagrees, because our specification derives from customer’s specification.

What is your opinion? Any opinion is appreciated.

It would seem to me that the tolerances were set too tight at the design stage. If the out of specification product is accepted every time without fail - that would sugest the tolerances permitted could be relaxed (assuming this doesn't have an impact further down the line) and that the manufacturing process wasn't taken into account when the customer designed the product (or you should change to a supplier who can meet the capability requirements)

I would have thought justifying a looser inspection criteria than the customer specified would be tricky at best in the event anything went wrong.

Have you discussed a drawing change with the customer? changing the drawing would ensure everyone was singing from the same sheet as it were & would avoid any complications later on.

Customer requirements are king - what they want, you deliver.

If the customer requirements are in reality so loose that they continually sign off concessions to accept parts with wider variations than the drawings state, then get this agreement formalized either permenatly through a change to the drawing or a by a process deviation (a limited in scope (by time, quantity or order number), pre-agreed concession). - If they suddenly get a new QA guy who sees things more black and white, you could be sitting on a hell of a lot of inventory which you cant sell and which you may struggle to get your suppliers to remake/rework

Or get better suppliers who are capable of building what you require. :yes:

It sounds like you should also be engaging in some DFM work with your customer to ensure that what they are asking is physically possible - there are potential cost savings for you, your customer and your supplier if they ask for what they actually need

Setting your own acceptance criteria lower than your customers has a huge potential come come back and bite you on the behind. It's just WRONG.

contract review.

Can you supply it? then do it and do it right. if you cannot supply it then enter into negotiations or no quote it.

I don't have any good advice, other that to note that we've been there as well...with a very much larger customer with ponderous and ineffective internal systems, and out-of-date documentation for many of their accessory products. They originally brought these products to us when another vendor dropped the ball for them. Their direction to us was along the lines of "you guys are experts at this stuff, figure out what we actually need and make it, we'll eventually fix the documentation". That was many years ago, and they're just getting around to sorting out their drawings and label specs with our help. That help mostly consists of our sharing our drawings and label specs, which have actually been controlling the products.

At least for us, quality/regulatory consciousness is a means of increasing, not decreasing, sales. Therefore we hypothetically might no-quote a job if we thought a customer had actual devious intentions regarding regulatory requirements, but we don't no-quote jobs just because a customer's quality competence isn't as high as we'd like it to be. We'd rather take the work, help them meet their customers' requirements, and do our best to nudge them in the right direction with regard to compliance.

I don't have any good advice, other that to note that we've been there as well...with a very much larger customer with ponderous and ineffective internal systems, and out-of-date documentation for many of their accessory products. They originally brought these products to us when another vendor dropped the ball for them. Their direction to us was along the lines of "you guys are experts at this stuff, figure out what we actually need and make it, we'll eventually fix the documentation". That was many years ago, and they're just getting around to sorting out their drawings and label specs with our help. That help mostly consists of our sharing our drawings and label specs, which have actually been controlling the products.

At least for us, quality/regulatory consciousness is a means of increasing, not decreasing, sales. Therefore we hypothetically might no-quote a job if we thought a customer had actual devious intentions regarding regulatory requirements, but we don't no-quote jobs just because a customer's quality competence isn't as high as we'd like it to be. We'd rather take the work, help them meet their customers' requirements, and do our best to nudge them in the right direction with regard to compliance.

Ah, but see, you are entering into negotiations.

Such a good discussion so far.

You can't change the customer specifications. No-no-no.

Nor can you make your specifications different and pass what I call the Straight Face Test.

You can, however ask for a waiver of specific requirements. Once permission to deviate from spec is received, it can be kept on file and your manufacturing tolerances set to match. The waiver would be expected to have an expiration point, or else a statement that it does not expire.

Talk/communicate to your customer. That is the first thing that you need to do. Ask them to increase tolerances.

Give them the data that you have on:

1. the quantity rejected

2. the quantity they have accepted via a concession

3. recommend that they increase the tolerances since apparently it doesn't affect form, fit, or function or they wouldn't be accepting them via the concession.


One question though, why would you go to a supplier that is not capable of meeting the tolerances?

One question though, why would you go to a supplier that is not capable of meeting the tolerances?

I think the deal here is that the customer has set tolerances that are beyond the range of capability, either through ignorance of the process, misinformation, or whatever. Correct me if I'm wrong.:o

I think the deal here is that the customer has set tolerances that are beyond the range of capability, either through ignorance of the process, misinformation, or whatever. Correct me if I'm wrong.:o

Since I haven't seen the drawings or the actual contract, I can't say that you are right or wrong here Steel.

actually, I meant the correct me thing for the OP. :lmao: But that's OK Coury, I'm just happy somebody wants to talk to me!;) Have a great day

actually, I meant the correct me thing for the OP. :lmao: But that's OK Coury, I'm just happy somebody wants to talk to me!;) Have a great day

Sorry Steel. I was quoted, so I presumed you were asking me.

The situation in our company is like this:
Customer gives us a lot of drawings. We forward the drawings to our suppliers and tell them to make parts according to the drawings. Suppliers agree.

The problem is: every time the parts sent by the suppliers have a large proportion (60% ~100%) that exceeds the tolerance limit. We accept them as concession each time because we conclude the suppliers don’t have the capability to meet the specification requirements. Besides, the parts, although exceeding tolerance limit, fit the assembly quite well. The customer, knowing the parts exceed tolerance limit, accept the finished product each time as concession.

Because it is common knowledge that we can not use the specification on the drawing to decide the acceptability of the incoming parts, each time we let QC inspectors do a preliminary inspection according to the drawing, then write a Discrepancy Report, then we let Quality Engineers do a second inspection on the defectives found, and make a judgment whether they can be used or not according to their manufacturability.

This process, of course, is wasteful, so I proposed to the quality manager that we should make incoming material inspection instructions for each part (currently they don’t exist), and the acceptance criteria on the inspection instruction should be slightly looser than the one provided by the customer’s drawing, so that the incoming parts can at least meet the tolerance requirements on our inspection instruction, although may not meet the tolerance requirements on the customer’s drawing.

My supervisor strongly opposes this idea, insisting that we can not change any customer specification. I argue that we do not change customer specification; we just change our specification, to make it closer to our actual capability. My supervisor disagrees, because our specification derives from customer’s specification.

What is your opinion? Any opinion is appreciated.You're bound to deliver to the customer's specification. You can


Discuss the issue with your supplier, if he can't improve then
Find a supplier who has the capability or.
Negotiate up front with your customer for the real requirement.

Why continue to waste resources?

Perhaps the "customer's specification" needs to be interpreted in light of the totality of information available. That's not to say that verbal business-agreement and contract-negotiation information can readily replace existing drawings and documented specifications, even when those verbal negotiations were documented via both-party-approved contemporaneous notes. However, such business-agreement negotiations can provide useful information as to when to not rely on those existing documents without further inquiry and instructions, in a context where the customer admits that his drawings and specifications are not reliable and he wants the supplier to act as a design-control participant in getting parts made and/or resolving the documentation/specifications problem.

Maybe the most important element of that perspective is the documentation of an acknowledgement by the customer and the supplier that the existing drawings and specifications have problems, and that specific steps are approved to deal with those problems while allowing the business relationship to move forward.

Thank you all. I think I know what I should do now. I have been in this company for about a month, still in probation period. Many things are out of my control. The suppliers have been supplying parts to us for quite a long time. By my direct supervisor -the quality manager's words, that we rely on our suppliers more than they rely on us.

Hi SteelMaiden you are correct. I don't think they ever considered the manufacturability during product design, because we have no supplier process capability data.