The Importance of Injection Mold Maintenance

Posted on 06-26-2017

Tool longevity is just as important to part cost and quality as the design and build. Regular, careful maintenance can prevent part failures and lower the overall cost of your injection molding program.

What is mold maintenance?

Mold maintenance, or tool maintenance, refers to the cleaning and repairs that are needed to keep an injection mold in the best working order. Maintenance is performed routinely over the life of the mold (preventative maintenance or PM), and also when any problems arise.

Why is mold maintenance important?

Many buyers overlook mold maintenance when choosing a supplier, but it’s actually a critical aspect of a successful long-term molding program. The condition of the injection mold affects the quality of the plastic components produced. Performing necessary preventative maintenance improves tool longevity and part quality by stopping issues before they happen.

What problems does mold neglect cause?

Over time, the molding process can cause wear on a mold. For example, a fine layer of material gradually builds up on the mold surfaces; if left unchecked, this vent deposit can dent the tool, causing flash and other unwanted part defects. It’s like owning a car. If you never perform regular maintenance, like changing the oil, the mechanical parts will experience wear, reduce running efficiency, and eventually fail.

Unfortunately, many molders will avoid doing maintenance until these quality problems arise or the tool breaks down. Repairing the mold at this point can be expensive and can jeopardize your part supply. However, if done regularly and correctly, preventative maintenance can improve production and lower the overall cost of owning the tool.


Download our guide, Diagnosing Plastic Part Failure, to learn how we assess part defects and molding issues.

What are the benefits of a properly maintained mold?

A well maintained (and designed) mold is key to producing consistent, high quality injection molded parts. Uniform cooling throughout the cavity impression (and from cavity to cavity in multi-cavity tools) will yield the highest quality part and the fastest cycle time.

Ensuring a quality mold requires well-designed tooling and higher precision build, both of which can increase the tool construction cost and regular maintenance cost. However, these measures will ultimately save you significant costs on repairs.

As a best practice, choose a molder that performs maintenance, such as cleaning parting lines during the production run, and has a dedicated service team that documents and tracks mold maintenance, to ensure that your tooling gets the long-term care it needs.

How can your supplier help?

Working with your supplier as a strategic partner can help reduce many of the risks and costs associated with injection molding. They can help you:

Optimize part design and mold design

The complexity of the part design drives the tool design. Working with your supplier to optimize both part design and mold design can improve the longevity of the tool and the quality of the part. Often simple feature changes can improve the robustness of the tool, simplify manufacturing, and ensure consistent part quality.

Make the most of your tooling investment

Achieving the “right size” for tooling budgets means optimizing the tooling investment for the type of part and volume required. Over-investing wastes money, but under-investing results in a shorter mold lifespan, supplier reliability issues, and added costs. Added expenses can include reactive tool maintenance while the tool should be producing parts, as well as overall mold maintenance and repair over the life of the tool.

Empire designs molds to make the PM process easier on the customer. We establish a unique PM cycle for every mold depending on the specific part design, industry, material, and other factors. By providing multi-level maintenance—ranging from a basic cleaning and wear assessment to a higher level teardown with a complete inspection—on a scheduled rotation that is fully documented at each service interval, we can ensure that your mold functions properly each time it is put to use.

Choose the right development tools

There are many options for making prototype parts. SLA, take-apart tools and other strategies can accelerate a project’s time to market. For specific applications such as high-cavitation precision parts with complex tools, a production intent prototype mold that replicates cooling, gating, and ejection strategies will lower the risks associated with production molds.

Empire also builds components so that they can be removed individually without having to disassemble the whole tool, which saves maintenance time and improves tool longevity.


To learn more about improving plastic part quality and cost through better tooling, download our guide.


Having issues with your tool? Sign up for Free Tool Troubleshooting with Empire; we’ll diagnose the problem and recommend a fix.


Editor’s note: This post was originally published in March 2015. It has been republished with new and updated information.