Category Archives: Structural Foam Molding

What Role does Resin Selection Play in Structural Foam?

| Posted in Plastics Manufacturing, Plastics Molding, Plastics Processing, Structural Foam Molding | Posted by

Anyone who works in the plastics industry understands how vital a role resin selection plays in injection molding, and how important it is to pick the correct resin for the correct product application. When it comes to structural foam molding, resin selection no different – choosing the right resin is critical for success. The base resin is the most important material component in the product development process, and performance will be dependent on the correct selection. Clear expectations and specifications need to be identified to be able to select the correct resin.

When creating a structural foam molded product, one of the top priorities should be identifying the type of resin being used. Understanding what the finished product is going to be used for is a good first step to take – several properties must be evaluated before choosing the right type of resin, including:

  • Chemical resistance – material that can resist most types of chemicals, such as acetones, ketones, oils, minerals, and acetates
  • Weather/environmental resistance – material that can withstand heat, corrosion, and oxidation
  • Temperature range – material that can withstand a wide range of varying temperatures
  • Flame Retardant—material that is burn resistant
  • Impact Strength – the ability of a plastic to absorb energy during plastic deformation
  • Flexibility – ability to bend and move without breaking

Since different resins offer different properties, knowing what application the plastic product will be used for is essential when choosing the right resin. With many resin classes to choose from, we have the opportunity to customize each product for every application.

What Types of Resin can be Used in Structural Foam Molding?

Once the resin has been selected, it needs to be capable of being molded using the structural foam molding process. This resin also must be compatible with other additives, such as colorants, elastomers, impact modifiers, and Chemical Foaming Agents (CBA).

Some high-quality resin materials to choose from for structural foam molded products include:

  • HDPE (High Density Polyethylene)—low-cost, weatherproof, and good chemical resistance
  • PP (Polypropylene)—good heat and chemical resistance
  • PS (Polystyrene)—strong and rigid
  • ABS (Acrylonitrile Butadiene Styrene)– good impact strength and rigidity
  • Polycarbonate – strong with good temperature range
  • PPO/PPE—excellent heat resistance and stability

The possibilities are endless when choosing a plastic resin for a particular structural foam molded component, but each resin should depend on what the structural foam molded part will be used for. The experts at DeKALB will help find the best type of resin for each structural foam molded component, no matter what the application.

The Structural Foam Process

Once the base resin and any additives have been selected, the molding process is ready to begin.  DeKALB focuses on low-pressure structural foam molding: during the molding process, the chosen resin mixes with a Chemical Blowing Agent (CBA) and/or nitrogen gas before being injected into the mold.  When injected, the combined material will create cells or bubbles on the inside of the molded part.  As the part cools, a solid resin layer forms against the mold, which will give it a solid exterior. The honeycomb structure of the molded part is rigid and strong, while at the same time making it lightweight and easier to move.

The DeKALB Difference

There are many benefits to utilizing structural foam molding to manufacture your components instead of other types of plastic injection molding. These benefits include:

  • Less energy waste – the structural foam molding process uses less energy per pound of plastic and uses less raw material overall
  • Increased performance – the structural nature of the resin in the component allows for better performance per pound.
  • Material variety – numerous types of resins can be used in structural foam molded products
  • Cost-efficiency – quality and easily-repeatable parts can be produced for less

DeKALB Molded Plastics is proud of the world-class quality reputation we have established in the structural foam molding industry. With a focus on continuous improvement, we achieve our high commitment to quality by adhering to clearly defined standards that help to control all process variables.

We have more than 40 years of experience serving our customers with high-quality structural foam molding services. With a wide range of capabilities in plastic processing and an experienced team of engineers, operators, and quality technicians, DeKALB Molded Plastics can handle any challenge.

Ready to see how DeKALB Molded Plastics can do for you? Click here to get your next project started.

Structural Foam Molding, It’s What We Do

| Posted in News, Structural Foam Molding | Posted by

As a custom structural foam molder specializing in large, multi-nozzle plastic products, DeKALB Molded Plastics has more than 40 years of experience serving our customers as a trusted business partner. We believe in structural foam because, at DeKALB Molded Plastics, we are structural foam!

The Basics of Structural Foam

A simple question that is often asked to us is, “what are the characteristics of structural foam?” Since structural foam is not a material but rather a manufacturing process, it’s not easy to answer this question. What is structural foam? Structural foam plastic molding is an injection molding process that utilizes a foaming agent and/or nitrogen gas that mixes with the base resin in the polymer melt before being injected into the mold.

What Materials are used in the Structural Foam Process?

As the case with most plastic manufacturing processes, polymers are used. There are two main categories of polymers, thermoplastics and thermosets. The main difference between the two is thermosets cannot be recycled, while thermoplastics can. At DeKALB, we primarily work with thermoplastics and can mold almost all of them. Under the thermoplastics umbrella lies three general groups of resins - commodity, engineered and performance. DeKALB Molded Plastics mainly focuses on commodity resins, but we mold many engineered resins as well. True to our commitment to providing unrivaled customer satisfaction, we have the flexibility and experience to work with all three types. In addition to the resins that we work with, DeKALB is also equipped to add additivities including talc, glass-fiber, impact modifiers and, in some cases, crumb rubber.

Structural foam has great recyclability, as parts molded in this process can be made from virgin material or recycled material. From there, the part, whether originally from virgin material or recycled material, can continue to be recycled, and subsequently, remolded again and again.

What Does DeKALB Molded Plastics Do?

Simply put, we mold big, heavy-duty thermoplastic parts. Generally, the guidelines for the parts that we produce weigh between 3 and 150 pounds, dimensionally parts are a 1’ x 1’ square, up to 4’ x 8’, similar to a sheet of plywood, and 30” deep. The thickness of the parts produced ranges from 3/16” to 3/8+” (4.7mm to 10mm).

We have the capabilities to go slightly outside of those boundaries getting close to 6 feet by 6 feet or just under 36 square feet. As always, depending on the application, there are some instances where we can go larger. As for the thickness of the part, we can go thicker or thinner, though when making a part thicker, it is usually more cost-effective to add strength with ribbing rather than thicker sections of plastic. Additionally, when making a part thinner than 3/16”, there are more considerations to make and pay attention to during the process.

DeKALB has a long and proud history of producing custom molded products for multiple market segments. Some examples of the products that we mold include:

  • Yellow barrels – (Seen on highways)
  • Pallets
  • Flooring
  • Underground enclosures

Can You Paint Structural Foam Parts?

From the color of your kitchen to the shoes that you wear, being able to customize something to get exactly what you want is important, and the same is true for the parts that we make. Providing custom solutions, in exactly the color you need, is just one of the ways DeKALB effectively serves our customers. Structural foam parts can be painted, and there are two ways to go about creating parts in a certain color. The part can be molded in color with colorants mixed in or color can be added during secondary operations. To meet your exact specifications, we either add colorant into the foam-resin mix or our in-house paint shop can meet the specific color requested.

We Are Structural Foam

Do you have questions about structural foam? Visit our structural foam FAQ’s.

When you work with us, you work with a partner that is committed to your solutions, providing the answers to your structural foam needs. With a wide range of capabilities in plastic processing and an experienced team of engineers, operators and quality technicians, DeKALB Molded Plastics is up to the challenge. Ready to discover what DeKALB can do for you? Contact us today!

Structural Foam for Seating

| Posted in Structural Foam Molding | Posted by

Everyone that buys a low-end plastic chair understands two basic things: one, the chair will likely be cheap and two, they will likely need to buy a replacement shortly after due to minimal construction qualities. What if these qualities could be enhanced in production? Structural foam provides the strength that will make chairs last. Whether it’s an Adirondack chair or stadium seating, structural foam produces a strong, durable plastic product at a cost reduction. Continue reading →

Value Added Services News

| Posted in Custom Mold Plastic Products, Custom Molding, Gas Assist Molding, Structural Foam Molding | Posted by

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

| Posted in Custom Mold Plastic Products, Custom Molding, Gas Assist Molding, Structural Foam Molding | Posted by

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.