Providing a one-stop-shop for our customers’ plastic and assembly requirements, DeKALB Molded Plastics utilizes three main plastic manufacturing processes to create our products: structural foam, gas counter-pressure, and gas assist. Beginning in the mid-1990s, our team began using gas assist as a way to enhance part performance and aesthetics with a footprint as large as 150 pounds and up to 30 inches deep.
What is Gas Assist Molding?
Gas assist molding is a process that uses pressurized nitrogen gas to hollow out strategically placed sections. During the process, plastic is injected into a mold, then gas is injected either in thick zones or in gas channels, depending on the part. For each part, our team works with the customer to determine the optimal settings for manufacturing the part, to achieve maximum performance while minimizing cost.
Once the resin is introduced into the mold, the nitrogen gas is injected into the polymer melt. The nitrogen forms hollow sections as it displaces the polymer in thicker areas, resulting in a significantly lighter cross-section. The gas assist method prevents sink marks and the ‘characteristic swirl’ that occurs during structural foam processing. In addition, cycle time is reduced due to faster cooling, equating to a lower cost component.
Benefits of Gas Assist Molding
Gas assist molding has many benefits:
- Faster cycle time
- Surface finish similar to injection molding
- Reduced cooling times
- Lighter part weight
- Lower piece part price
- Integrating localized design features
Applications of Gas Assist Molding
Typical uses for gas assist molding include:
- Hollowing out a localized thick area
- Generating stiffening sections across a part
- Performing the pack phase of the process
Each of these reasons provides a different benefit. Hollowing out a thick area of a part also allows bold design features. Gas assist can also be used to increase the structural integrity of a part by producing stiffness across the part. Finally, using gas assist molding to perform the pack phase of the process allows a part to function in a smaller press tonnage, which lowers overhead.
When weighing the benefits of different ways to mold a part, the gas assist molding process is often chosen because of the benefits of not having the swirled pattern common to foamed products. Overall, gas assist molding produces parts with more attractive cosmetic surfaces.
What Products are Created Using Gas Assist Molding?
Everything including air compressor parts, medical equipment housings, refrigerator door handles, heater shrouds, bleacher seats, and utility carts. The possibilities of what can be created through gas assist molding are limited only by our imagination.
Does the Design of Gas Assist Molding Require Additional Considerations?
During the tooling design stage, tooling is adapted to direct gas into predetermined areas hollowing out up to 15% of the total volume.
To learn more about gas assist molding or any of our processes at DeKALB, contact our committed team of experts today!