Mold release agents are formulated to increase productivity, while producing consistent parts with less scrap. Yet, it can be difficult to gauge the proper amount to use in order to get the best results and maximize cost savings.

You want to use an amount of mold release agent that releases parts easily, while keeping molds relatively clean. The surface of your finished parts also needs to be acceptable. Parts should be slippery, but not greasy. Using the right amount of mold release can also improve your bottom line, reducing scrapped parts and cutting your overall costs.

Here are some guidelines that can help you determine the correct amount to use, along with some tips to see if you are using too much or too little in your current production process.

How to Test Mold Release Usage

The amount of mold release you should apply will depend on the parts you manufacture, the types of resins or other materials you use in your molds, the temperature and pressure requirements involved in your molding process, and other factors. That’s why it can be helpful to test your process with varying levels of mold release agent to discover the amount that produces the best results.

Clean Your Molds Before Testing

To perform a proper test, be sure to thoroughly clean each mold to remove any traces of mold release or other debris. This ensures the test accurately reflects the performance of the mold release agent amount used for testing.

Perform Consistent Tests

It’s important that the conditions don’t change during your testing. That’s why we recommended performing your testing during a single press operation with the same operator performing each test. That way individual differences in operator methods won’t affect the final results.

Evaluate the Number of Parts Released

To begin the test, apply the usual amount of release agent to the molds and evaluate how many parts can be successfully released. Note when parts begin to stick or hang up, indicating the need for another coating of mold release.

Next, perform the same tests again to verify the results. You may want to run several rounds of testing.

Finally, perform the same tests using more or less mold release to see if you can improve your results.

When your testing is complete, you should arrive at the optimal level of mold release agent to use for the parts and procedures you’ve tested. Be sure to train your staff to use the correct amount during each operation to achieve best results.

Run Tests on Your Most Difficult Parts

If you don’t have the time or resources to perform testing on all of your molding processes, at least evaluate the amount of mold release you use on your most difficult parts. This gives you the best opportunity to improve your process and realize significant cost savings.

Signs You Are Using Too Much Mold Release

Many operators use too much mold release in an effort to prevent sticking parts. But more isn’t necessarily better. In fact, over-application of mold release agents is one of the most common problems that can lead to unsatisfactory results including:

• Blisters, voids, or knit lines on finished parts
• Variable surface finish on de-molded parts
• Parts that are missing critical fine details

Using too much mold release also wastes money, both on inferior parts that end up as scrap and the need to purchase mold release more often.

If you are observing any of these issues, you’re probably using too much mold release and should revisit your application process. For best results, apply a light mold release application at every part or shot, and be sure to clean tools regularly to avoid build up.

Signs You Are Using Too Little Mold Release

While a little mold release can often go a long way, it’s still important to use enough mold release to produce consistent quality in your finished parts. How will you know if you aren’t using enough? You might experience any one or all of the following issues:

• Parts frequently stick to the mold
• Remove mold too frequently due to resin build-up
• Normally glossy parts have a dull finish
• Parts feel dry or rough after de-molding

If you’re observing any of these issues, it’s time to take a look at how much mold release you’re using and whether it’s being applied consistently.

As you can see, gauging the right amount of release agent to use for your molds can be a fairly straight-forward process. It’s simply a matter of testing the amount you use and observing the results of each test. Before you know it, you’ll be producing precision parts with more consistency and less scrap, increasing productivity, and improving your bottom line.

Need help with your molding process? Talk with our molding experts!

Stoner Molding Solutions has been helping manufacturers mold more parts in less time since 1942. We offer a full suite of mold release agents for the thermoplastics, polyurethane, composites, and rubber industries. Our industry-leading chemists and engineers are here to listen and provide honest value. Request a free sample to test our products for yourself!