Measuring up to Snuff

Published On: April 5th, 2023|Categories: Blog|

At PlastiCert we have long prided ourselves on our ability to make tight tolerance parts. Being able to do so is doubly hard, as first the part’s dimensional requirements need to be reflected in the making of the mold. Then, the material and injection molding process need to be managed to accommodate those variables as they also contribute to a final part’s dimensions.

After all that is said and done, we need to verify the part in hand meets it’s design print. For the last 20 years, we used a Coordinate Measuring Machine (CMM) to measure parts and qualify molds and processes. In fact, the same CMM was used all that time. A quite reputable and consistent CMM, but as with all things, it’s age makes it susceptible to possible downtime. It’s age also implied that when downtime occurred, getting replacement parts might have been an issue.

So, we included a new CMM in our Capital Improvement Plan and executed it 3rd Quarter last year.  A Hexagon  GLOBAL S Green 5.7.5 CMM arrived on our loading dock, and we have been putting it to use ever since.


PlastiCert routinely molds parts that have tolerances of + or – 0.005 of an inch. We often look to repeatedly mold parts that require + or – 0.001 inches on specific features or surfaces. Our new CMM is capable of measuring 0.0001 of an inch, but those types of tolerances are rarely attempted much less produced in production. Primarily because all injection molded plastic shrinks as it cools. Just how much varies greatly from resin to resin. The typical window for shrink rates is many times wider than a molder would like. It is then that skill and experience allows the  molder to work the mold design and process to qualify the part a customer is looking for.

We have worked with a customer to design a prototype mold to bear out a tight tolerance design, and the resulting part was so good the customer wanted to take that mold directly into production.  


Having trouble getting the parts you want because of dimensional tolerances? Been told no, what you want is not possible?

Give us a call. We’ll take a look at what you have and render our own opinion as to its repeatability.

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