Injection molding is the most popular mass production method when creating large volumes of identical plastic parts — and for good reason. While you may need to invest a significant amount of money upfront to manufacture injection mold tooling, your price per unit will be extremely low if you produce parts and will continue to drop as you make more pieces. A complete injection mold system consists of a mold base and one or more sets of core and cavity inserts — these inserts are the primary components that mold your part. However, you may also see the more general term “mold” being used, which typically refers to the combination of the core and cavity insert pair.


Depending on the size and complexity of the part, the cost of a mold could run you tens of thousands of dollars. This accounts for the parts and assembly of the injection mold. On the other hand, modifying a mold can save you time and hundreds to thousands of dollars. However, the type of changes being done to a part is a major deciding factor when it comes to which option is available to you. Regardless of the decision, to increase the longevity of your molds – modified or brand new – you should invest in regularly scheduled maintenance and repair.

When you need to adjust the size, design, or part function, you’ll have to tweak your injection molding process. In doing so, you’ll have to decide how these changes will be made — which raises the question: do you modify your molds, or make new ones altogether? In many cases, using either a new or modified injection mold can get the job done. However, you should know that the cost of creating a new injection mold is higher than simplifying an existing one. Even making simple molds can easily run up to thousands of dollars. This cost will increase depending on the size and design of the part.


Due to the associated costs and time, it is not very appealing to have to make a new mold tool from scratch, but there are some situations where it isn’t possible to alter an existing mold and achieve your desired results. You may need to manufacture a new injection mold if you need to Reduce the size or shape of your product: Since it’s potentially costly and very difficult to reliably add metal to an existing mold, if you need to shrink the size of your part, you may need to manufacture a new set of mold inserts.