Category Archives: Gas Assist Molding

Gas Assist Molding

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!

Value Added Services News

At DeKALB we offer an array of value added services to complement your molded plastics needs. We pride ourselves on the ability to provide our customers a wide range of services.

Our team has the ability to utilize existing products and fabricate them to create customized components. Our capabilities include cutting-straight and angles, assembly, bonding, welding, inserting, routering and drilling. At DeKALB, we also providing painting services, utilizing both solvent and water based painting systems with complete masking capabilities. We provide numerous painting systems, including: acrylic, water, and urethane based, as well as multiple masking, color, and textures.

DeKALB provides complete plastic and assembly solutions, from simple sub-assemblies to complete assemblies that are packed and shipped right to your customers’ door. We have the capabilities for sonic and induction welding, enclosure and component assembly, bonding and emabonding. We also have the capability of specialty packaging, bulk packaging, and consumer-ready packaging with custom labels and decals.

Our numerous years of experience in the manufacturing industry guarantees the highest quality products at the right price. We keep track of these products with our inventory management systems. These solutions reduce your work load and increase the efficiency of your supply chain.

At DeKALB, we are constantly looking for new ways to make operations for our customers more efficient.

Custom Molded Plastics

Custom molded plastics are the heart and soul of DeKALB Molded Plastics. DeKALB is one of the first ISO 9002 certified structural plastics molders in the United States. With presses ranging in tonnage from 300 to 750 tons and over 30 years of experience in the structural foam industry, there isn’t a project the team at DeKALB can’t tackle with precision and quality.

DeKALB specializes in large, multi-nozzle plastic products while offering in-house painting, decorating, kitting, and assembly capabilities. Deliverables range from single stand-alone products to complex, multi-component, multi-operation programs.

DeKALB’s product offerings are diverse and focused, including:

In the Specialty Material Handling market, DeKALB produces rigid plastic pallets, folding transport boxes (for bulk and liquid products), and other applications that protect valuable and perishable household items (food, textiles, and medical components). In the Medical market, DeKALB produces a variety of intricate products, ranging from ultrasound and densitometers to MRI helmets and medical beds. Their main concentration is to produce products that contain, support, and protect medical equipment. DeKALB’s Safety Enclosures and Devices focus on protecting and preventing individuals and property from harm with the creation of barriers, stands, and guardrail blocks.

DeKALB has perfected two main plastic manufacturing processes: structural foam and gas assist. Structural foam molding (Fig. 1) is a process in which foamed plastic flows through the mold, surface cells explode, and a solid skin forms against the walls of the mold. Meanwhile, the core of the newly created part cools to a cellular structure. The end result is a part which is up to 20% lighter and three to four times more rigid and durable than solid plastics. This innovation can replace a myriad of materials, including wood, metal, concrete, and fiber glass.

structural-foam-molding-process

The gas assist molding process (Fig. 2) utilizes nitrogen gas that is injected into the polymer melt as soon as the resin is injected into the mold. The nitrogen displaces the polymer in thicker areas, hollowing out the part and making it significantly lighter. This is a low-pressure injection method that 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.

gas-assist-injection-molding-process

Beyond competitive pricing, DeKALB prides itself on superior customer service, warehousing capabilities, and on-time deliveries. One glance at the Client Testimonials page on dekalbplastics.com tells the story of DeKALB’s consistency, quality, responsiveness, competitive pricing, and technical support.

What is DeKALB's plastics manufacturing size capabilities?

Transcript:

Many people come to DeKALB Molded Plastics because we can make large parts. Large parts, structural foam, gas assist, very, very well. We can make products up to 150 pounds at our facility, but really it’s the type of process that we can do. Because they are so large, we can be cost effective with the rate reduction, and again, providing the characteristics that you need for your large part. We present warp, creep, all the building stresses that come with an injection molded part go away with structural foam.