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Inspections of moulds and tools in China

by Renaud Anjoran

Many buyers want to have a Chinese manufacturer work on their own designs. And, very often, it means mould(s) need to be created for each new product design.

But creating a mould is expensive. If the supplier does not already know the buyer, he will probably ask the buyer to send a payment.

In the importer’s side, it means they need to send money to a new supplier (who has not demonstrated his ability to produce at the right quality standard).

And then, to send money again before production starts (the famous “deposit” which is actually an advance payment).

It is understandable that the buyer wants to check whether the moulds were done right. But how to check the mould’s quality?

Here is what I usually write to clients who need an inspection on plastic injection moulds.

Regarding the material composition

You want to make sure the steel is hard enough. But how to make sure about this?

In the best case, the factory has XRF testing capability.

If they do not have the capability, the inspector can ask for certifications of materials. Sometimes they are fake, but that is not as frequent for moulds or tools as it is for a production batch.

Another option is to send samples of the tooling to a testing laboratory. They will run a chemical analysis, and confirm whether the grade of steel you requested was in fact used.

Regarding the dimensions

There are two cases:

1. You gave the drawing of the mould/tool to the supplier.

In this case, all we need to do is checking the mould’s dimensions.

In an ideal world, the manufacturer should have CMM testing capabilities. If not, using calipers is possible but not very precise.

Another option is to ask the manufacturer to physically bring the whole mould to a testing laboratory that has CMM capability.

2. You only gave the drawing of the finished product (to be made with the mould) to the supplier.

We will need to know the material of the finished products, because we need to estimate its shrink rate (after it gets out of the mould). For example, nylon has a higher shrink rate than polycarbonate.

We can use software to estimate by how much each dimension will shrink, and it allows us to know the dimensions the mould should have. And then, we can use CMM or calipers to estimate whether dimensions are right (back to point 1).


Renaud Anjoran has been managing his quality assurance agency (Sofeast Ltd) since 2006. In addition, a passion for improving the way people work has pushed him to launch a consultancy to improve factories and a web application to manage the purchasing process. He writes advice for importers on qualityinspection.org.

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