Designing for Injection Molding: 3 Tips for Seamless Production

design for injection molding

Plastic has a lot of value in our daily lives. It’s versatile, sturdy, and easy to mold into various shapes. However, it’s important to use it economically and sustainably since plastic production has doubled in the last 20 years.

Here, we’re going to talk about how you can create a usable and efficient design for injection molding. Read on for some tips on making high-quality parts with minimal waste and lower costs.

1. Keep Wall Thickness Uniform

Many injection molding parts have several walls between hollow sections. These walls don’t just construct the overall shape of the part but also hold it together.

It’s important that each wall has the same thickness. If they’re uneven, the part will cool unevenly inside the mold. This can cause warping and sinking as well as weakness in the useable part.

However, some parts naturally do have sections that are thinner and thicker than other areas. This is still completely within the capabilities of injection molding if you know how to transition between thicknesses.

Don’t move immediately from a thick section into a thin one. Instead, gradually taper the amount of plastic off until it’s the appropriate thinness. This stops some areas of the part from becoming weak and snapping.

2. Avoid Undercuts Whenever Possible

Most injection molds are “straight-pull molds.” They’re made with two halves that pull apart after the plastic inside has cooled and solidified.

Some people design parts with undercuts for injection holding. Undercuts are anything that makes it complicated for the part to come out of the mold. In some cases, these undercuts stop the mold from releasing the part altogether.

When possible, don’t design a part with side holes, vents, or slots. Protrusions like snaps and latches also can inhibit the part’s removal from the mold.

If you do need to include an undercut, move the parting line of the mold so that it intersects with the cut. Adjust the draft angles to accommodate this.

Undercuts are unavoidable sometimes when creating precise parts, and a professional plastic part manufacturer can help you contend with them.

3. Make Part Removal Easy

Part of designing an injection mold is creating gates and inlets to help the part come out of the mold in one piece. Make sure that the gates are at the thickest parts of the plastic. This will stop the part from getting damaged while ensuring that the filling remains uniform around the gate.

Ejector pins are also important for part removal. Put them in ribs and other reinforced parts of the final product. This will stop them from snapping or warping when removed from the mold.

Create a Great Design for Injection Molding ASAP

Now that you have some tips on creating a part design for injection molding, it’s time to talk with an expert about your next project.

Nova Stevensville’s team is excited to help you create a mold for the mass production of car parts and other plastic items. Reach out to us today to ask for a quote for your project.

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