Creating a custom molded plastic part can seem like a daunting task–but we’re here to make it seem a little simpler! From product design to the actual injection of the plastic into the mold to the final assembly, learn about the journey your custom design for a plastic component will take in injection molding.
- Part Design and Development
The first step to making any custom molded plastic part is finalizing its design. This involves engineers and part designers working together to create a design that not only meets the necessary functional requirements, but also will be manufacturable through injection molding. Using CAD software to make a three-dimensional design that they can then examine and adjust for features such as supporting ribs, draft angles for ejection, and bosses for inserts. CAD files also help the development team avoid features such as non-uniform wall thickness, abrupt geometrical changes, and undercuts or overhangs that would interfere with the process. - Building the Mold Tooling
The most important part of any injection molding process is building the actual tool itself. The mold tooling is designed and manufactured based on the design of the product, and carefully made to contain everything that’s necessary to ensure injection molding is possible. Mold tooling is usually made from specific grades of steel, but can also be made from aluminum depending on the plastic being used and the production volumes of the project. - Preparing the Plastic and the Mold
Once the mold is built and finalized, it can be installed into the injection molding machine. The plastic pellets of whatever material is being molded are then melted and kept at a constant temperature depending on the material specifications. Temperature control is critical in injection molding, and should be carefully monitored throughout the entire process. - Injecting the Plastic
Now that the plastic has been melted and the tooling is in place, the molten plastic can be injected into the mold. This is done through a nozzle, pressurizing the plastic in the process so that it fills every part of the mold cavity. The plastic is then held at a set temperature and pressure, and cooled carefully while maintaining that pressure for uniform solidification. While this is happening, the next batch of plastic, called a ‘shot’ is prepped to continue the cycle. - Ejecting the Part
When the custom molded plastic part has fully cooled, the mold opens, allowing it to be ejected into a waiting barrel. Then, it closes and the cycle can begin again.
Final Steps
After the parts have been ejected and the batch is done, some molders like World Class Plastics also perform a variety of other value-added services such as assembly, pad printing, and more. Once everything is done, the parts can be packaged and shipped off to their next location for the assembly of the end-use product.
About World Class Plastics, Inc.
World Class Plastics, Inc. is an expert, full-service supplier of custom molded plastic parts across the Midwest. We provide everything from engineering and product development to prototyping, mold making, tooling, injection molding, and value-added services, all in-house! Check out our website to learn more and request a quote on your project!