AIM Processing Small Plastic Parts Blog

One of the more interesting challenges we get at our small part plastic injection molding operation in the Denver area is how to design a plastic parts manufacturing process in a way that produces the best assemblies. When two or more finished parts must fit together properly to make one assembly, there are a number of factors to keep in mind.

Designing Small Plastic Parts for Assembly

The key to designing parts for assembly is to be very aware of tolerances. When multiple parts with multiple tolerances must fit together, the parts must be designed and manufactured in such a way that they can account for some level of difference between the model and the finished parts. In particular, here are some things to keep in mind:

• Shrink rates. Different materials have different shrink rates. It’s critical that everyone from the part designer to the operator at your plastic injection molding company understands what those rates are and how they will impact the way finished parts fit together to create an assembly. A word to the wise here: be sure all the stakeholders discuss shrink rate before you start production runs.
• Color matching. When different base resins are used in the components of an assembly, it can be very difficult to match colors between the parts. Even though technically the same shade is used in both parts, aspects of the material like surface lustre can result in colors that are a close match, but not an exact match. One way to deal with this is to design your assemblies using complementary color. For example rather than having the two halves of a blue part look somewhat “off” due to slight color differences, you might create assemblies that are blue on one side and orange on the other.
• Securing the parts of an assembly together. There are many methods for connecting the parts of an assembly. They include snap fit, interference fit, screws with inserts, self-tapping screws, and ultrasonic welding. Each of these methods poses unique challenges when it comes to ensuring that components fit together properly. Once you’ve decided on an approach, it’s important for the designer and your plastic injection molding shop to discuss the plastic parts manufacturing process and how it can be best executed to produce high-quality assemblies that fit together properly.

Decades of Experience in all Types of Plastic Parts Manufacturing Processes

While designing for assembly can be challenging, with a little bit of forethought and the skill and experience of a small plastic part injection molding company like AIM Processing, there’s no reason you can’t produce parts that fit together like hand and glove. In our more than 20 years in business, we’ve seen all kinds of assemblies. If you have questions about the design for your next project, don’t hesitate to contact us. We’re happy to discuss your objectives and work with you to ensure that you can achieve them.