When designing product for injection molding it is important that the design firm and the client work through the design criteria together to insure a successful outcome. Sometimes the client feels it is best not to reveal everything about a product for security and
confidentiality reasons. I would strongly suggest that you work with a firm that you trust so that you can reveal everything you can about the product. The design firm should be able to expand on the design criteria with a thorough understanding of the products intent.

When it comes to injection-molded plastic designs, there are often more questions to be answered than the client originally expects. That’s why client communication is critical: developing the performance criteria is dependent upon having a clear understanding of what the client needs the item to do. The design firm is the expert in product development, and it’s the firm’s job to ask the right questions about the product’s intended use, and make sure that the design criteria accurately and fully cover all aspects of that use.

That may seem like an oversimplification, but it’s not beyond reason to develop a set of design criteria, fulfill them completely, and still not have a working product. While the firm which does this may get paid for their efforts, the firm which recognizes a problem and prevents it from happening will also earn a client’s loyalty.

Understand if the idea of “working” focuses solely on the prototype, or on the manufactured item, as well. If it’s the latter, each of the design criteria must be double-checked as the prototype tool is created. Injection molding is a different process than 3D printing: while the latter places tiny drops of material upon each other until the parts are formed, the former injects liquid material into a mold, and how that liquid flows may change how the product behaves. By taking those extra steps we can deliver an item which is ready for full-scale production.

If there’s a minimum amount of force required to pull two pieces apart, or a hinge must rotate a given number of degrees, will the firm know to make sure that those criteria are still met when the item is created using the prototype tool? As the material flows into the mold, does it fill it completely, or are there air pockets created by the shape of the product? Do the living hinges work properly? Are there other flaws which might crop up during injection-molding which weren’t evident in a 3D-printed prototype?

Solving this kind of problem can be as simple as tapering edges by a tiny amount to make sure that the parts pop out of the mold smoothly, yet still perform their function once assembled. Catching such issues requires software that performs flow analysis as the tool is designed. Once that analysis is complete, the prototype tool should be put through its paces just as thoroughly as the prototype was. What comes out of that tool (and it should pop out smoothly, without snagging or breaking) should fulfill the very same design criteria that the prototype did.

Product development of injection molded product takes a lot of skill, experience and talent. One of the skills that the design firm should have as well as all of the technical skills is good communication. This includes not only updating the client on the development of the product but also pointing out all of the possible roadblocks by discussing the product in depth and helping to develop a good design criteria.

Do you have a project that requires injection molded plastics? Let us know.

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