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Design for Moldability Toolkit

Get in-depth design advice to optimize your plastic parts for injection molding. Designing with moldability in mind can accelerate production time and reduce production costs

Optimizing Part Design for Molding

There are many design elements involved when creating plastic parts for injection molding—design for cost, design for quality, design for assembly, design for manufacturability. And navigating that landscape can be challenging at times. At Protolabs, we provide automated design analysis on CAD models that highlights features in your part design that can be adjusted for moldability. It’s a great design resource to have at your fingertips. To keep those moldability advisories at a minimum and optimize your part design, we created this helpful kit of different injection molding resources.

Designing Complex Features for Molded Parts

Undercuts
Bump-offs
Side-actions
Shut-offs
Core and Cavity
Wall Thickness

Navigating Critical Molding Advisories

Insufficient Draft
Gate and Ejector Pin Layout
Radii Added
Non-metal Safe Changes


 

Designing for Moldability

See how designing with moldability in mind can help you avoid manufacturing advisories in quoting, save you development time, and reduce production costs.


Design software

A Beginner's Guide to Injection Molding

Whether you’re new to the injection-molding process or a veteran of manufacturing, Designing for Moldability is a quick reference guide to wall thicknesses, surface finishes, tolerances, materials, and other thermoplastic molding insights. It’s a thorough look at injection molding that might just provide a few tips to help you make better parts.

Undercuts

Undercuts are features like clips or thru-holes that can’t be milled in a standard vertical (Z-axis) milling setup and would otherwise prevent ejection from the mold. Learn about designing for cams and inserts to accommodate undercuts in your part.

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Bump-offs

Green blue part illustration

Bump-offs are small undercuts in a part that can be formed and safely ejected from a mold without the need for side-action cams. Learn about the types of features and geometries that are good fits for bump-offs. 

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Side-actions

Side-actions, also referred to as side-pulls and cams, are mechanical components in the mold that are used to form undercut geometry. Side-actions are pin-actuated and move based on the opening and closing of a mold. Learn about how to use side-actions to accommodate undercuts here.

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Shut-offs

A shut-off refers to any two faces in a mold that come together when a mold closes to “shut-off” or divert the flow of material inside of the mold cavity. Some shut-offs, referred to as sliding shut-offs or pass-thru cores, are used to form undercut geometry. Learn how to incorporate shut-offs to form undercuts here.

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Core and Cavity

In an injection molding press, one half of the mold (the A-side) is attached and fixed, while the other half of the mold (the B-side) is attached to the moving clamp that opens and closes the mold. Learn how to choose proper core and cavity placement here.

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Wall Thickness

Wall thickness is a prime consideration in the molding process to ensure dimensional stability and consistency while a part cools and hardens. If walls are too thin, it might weaken the part and prevent filling. If walls are too thick, it might cause the part to warp or sink. Learn how to incorporate consistent wall thickness here.

See Guidelines

Navigating Critical Molding Advisories




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Tour Our Injection Molding Facility

Want a peek behind the curtain of our injection molding process? Take a virtual tour. We offer a fully digitized injection molding process to bring you cost-efficient parts fast. From design upload to quoting, from part production to shipping, it’s injection molding tailored to fit your needs, every step of the way.