As a business evolves, so too do the parts it requires. A company may need to adjust the size, offer more variations, or make changes to a product based on feedback. For businesses that get their parts from injection molds, they have to decide on how they want to change the produced parts. Some alterations simply require one to modify their existing mold, while others may call for the creation of an entirely new injection mold. In this blog, we will discuss which option would work best for your needs.

Which Method Costs More and Why?

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.

Under What Circumstances Can You Modify an Injection Mold?

While modifying an existing mold is the less expensive option, there are limitations to what can be modified. If you are making the following changes to your part, a mold modification is a great option:

• Expand Part Geometry: Although there are minimal increments at which metal can be removed, increasing the part size or wall thickness is possible by removing metal from an existing mold.
• Add a Smaller Part: In some cases, if there is enough room in the tool, a small part with a similar style can be installed with a shut-off separating it from the initial cavity.
• Core Replacement: If a part needs to be made small but maintain qualities of the original design – such as threading – the mold can be kept as is and just the core replaced.

To increase the chances of future modifications to a mold, inform your supplier if you believe you will have any reason to adjust or tweak your part in the future.

When is Building a New Mold Recommended?

Although more expensive than refashioning a tool, there are circumstances where a new mold would be required. Some changes that would require a building a new mold include:

• Shrinking a Part: While sometimes replacing the core is the solution, a part undergoing minimization at multiple dimensions requires a new mold. Metal cannot be added to a mold.
• Changing the Resin: Different types of resins shrink different amounts and molds are made to accommodate such shrinkage. Changing the type of resin may mean building a smaller mold.
• Parting Line Change: Expanding a part at the parting line most often requires a new build, as it can negatively impact venting and gating features.

Of course, the price of a new mold varies depending on a few factors, as discussed in our blog, Answering Your Injection Molding Questions: Part One. There are limitations to what can be done, which is why sometimes you can save time and money by modifying a mold or sometimes building a new mold is the only option. Here at Midstate Mold & Engineering, we have the capability of making and modifying molds right in our shop, which not only saves time, but it also allows us to assume full responsibility for the design. If you have questions about mold building or modification, contact us today.