How Can I Make My Thermoplastic Injection Molding Process More Efficient?

Oct 27, 2022, 10:37 AM by The Stoner Molding Solutions Team
If you’re in the molding and manufacturing field, you likely already know that thermoplastic injection molding has a wide range of uses and increases in popularity yearly. With that popularity comes increased pressure for you to mold more parts in less time.

A lime green injection molding machineIf you’re in the molding and manufacturing field, you likely already know that thermoplastic injection molding has a wide range of uses and increases in popularity yearly. With that popularity comes increased pressure for you to mold more parts in less time. If your mold cycle time takes too long or the parts you produce aren’t high quality because you’re trying to rush the process, then you face an efficiency problem.

By understanding the process and common materials used in injection molding and measuring the right metrics, you can begin to understand how to make your plastic molds more productive. Additionally, continually improving your manufacturing process can make your process more efficient.

One improvement that can make a significant difference is the products you use on the molds. Mold cleaners are essential to eliminate dirt, grime, and other residues that can cause defective parts. Mold sealers help fill in the mold's microporosity to produce a consistent surface finish. Mold releases help you to release the molded product quickly and effectively from the mold surface and decrease scrap parts.

Stoner Molding Solutions has specially formulated products to help improve the efficiency of your thermoplastic molding operations, allowing you to achieve a higher output of completed products in less time. Get in touch with our experts today to see how we can help you get more products molded more efficiently.

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What Is Thermoplastic Injection Molding?

Thermoplastic injection molding is a manufacturing process to create high-quality plastic parts quickly and efficiently with a consistent surface finish. Pellets made from various thermoplastic polymers are added to a hopper of a molding machine, which are then passed into a heated barrel.

With a corkscrew-like action and heat, the barrel melts the pellets. Then, the material is injected at high pressure to fill the plastic molds completely. After it is cooled, the molded parts are released by opening the mold.

What Are Some Common Polymers Used for Injection Molding?

With thermoplastic injection molding comes high-quality parts that are greatly accurate and easy to produce in large numbers. It’s no wonder many industries—from automotive and medical to household tools and toys—use this molding process to create plastic parts. Some of the most common thermoplastic materials used in plastic injection molding include:

  • Acrylic – With hardness comparable to aluminum, acrylic is ideal for many products, including lenses and control panels.
  • Acrylonitrile Butadiene Styrene (ABS) – This material provides high impact strength, durability, and scratch resistance to items such as radiator grills for cars, laundry irons, hair dryers, and more.
  • Polyethylene – A high-density type of plastic, polyethylene is suitable for more intense applications, such as fuel tanks and refrigerator containers. Its inherent properties include high-heat distortion temperature, stiffness, and chemical resistance.
  • Polypropylene – This thermoplastic resin provides flexibility, longevity, and chemical resistance. This material will be molded into things like plumbing equipment and washing machine drums.
  • Polystyrene – Its high gloss and transparency make this plastic one that manufacturers often add dye to change the color. It’s often used in packaging and the toy industry.

What Metrics Should I Measure in my Plastic Injection Molding Operations?

When creating thermoplastic molded parts, you want a high output of quality parts. To ensure your process is as efficient as possible, you should be measuring the following metrics:

  • Mold cycle time – the total time required to mold a part, from when the pellets are added to the hopper to when the completed piece is ejected, and the mold is closed for the next cycle.
  • Theoretical cycle time—the optimum amount of time required to produce a completed part. If actual cycle times take longer, it may indicate a problem with the mathematics or with the machine settings. If actual cycle times are shorter, you may have a quality problem with your finished product.
  • Average cycle time – Add up the total time to produce a run of products by the number of parts produced.
  • Number of defective parts produced – Amount produced per cycle
  • Total downtime – Including when the mold has to be taken out of production for maintenance and when operators need to pause to reapply the mold sealer, cleaner, or release.
  • Maintenance schedules – When a machine is due for routine maintenance, how long it was out of service, and when it was brought back into service.

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How Can I Improve My Thermoplastic Molding Efficiency?

When you notice some of your metrics dropping, you may be concerned that you won’t meet your necessary deadline to get the products to the market. To improve your economic efficiency, you can try various strategies, including:

  1. Optimize your machines – A thermoplastic molding operation is only as successful as the machines used in the process. Ensure you have performed regular maintenance when necessary, calibrate the machine properly, and optimize factors such as heat, pressure, and ejection speed for the type of plastic molding.
  2. Manage your inventory – Nothing is worse than having a productive day only to run out of the plastic material you need to complete the job. Ensure that processes indicate when you are running critically low on a much-needed supply. Inventory management models, such as Just in Time and Kanban, are ways that you can ensure you always have enough supplies on hand.
  3. Train your machinists – Cycle times can often be delayed or improved based on the machine's operator. Every action and decision they make can control the output of the materials. Regular training refreshers and coaching can make a difference in your molding efficiency.
  4. Try a different machine – Not all machines are equal. Some machines may produce parts faster than others without compromising quality. If all else fails, give a second machine a run-through to see if your molding process can be more efficient.
  5. Use the right molding products – Your molding efficiency can be greatly improved by choosing mold releases, sealers, and cleaners that work effectively, such as the ones we sell. If you deal with frequent sticking parts, defective surface finishes, or build-up on the finished products, your mold releases may be to blame.

Try the Best Thermoplastic Injection Molding Products on the Market!

If you do not see the results you want from your thermoplastic injection molding operations, then it’s time to try our mold releases, sealers, and cleaners. We have specially designed these products with your industry in mind. Our products can help you optimize your cycle time, produce a consistent surface finish, minimize mold flow lines, and more. Get in touch with one of our experts today to see which products are right for you!

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