

Custom Rigid Molded Parts Ace Cost, Delivery and Detail Requirements
What do munitions storage structures, faux-wood shutters, kayak paddles and fuel floats have in common? They’re all examples of custom rigid molded parts. From ongoing cast part programs to high-volume runs for a discrete application, we’ve been providing customers with a fast-cycle, low-cost, highly detailed alternative to machined parts.
Molded parts, also known as cast parts, involves using a two-part urethane formulation, and utilizing a mold or tool for a specific shape. This method of producing large volumes of rigid parts serves as an efficient option to machining or carving high-density rigid polyurethane foams.
A company using our materials have two options for the rigid products: We offer built-to-print parts as well as sheet stock. The manufacturing process for build-to-print parts is ultimately driven by the project and requirements. The primary benefit of molded parts over machining is reduced cost-for-volume sale and achieving geometric complexity.
The CNC route may work for projects with simple shapes at high volume. However, in a casting process, with even medium-sized complex shapes, pouring can be more advantageous since one can get more cycles with less labor, driving the part cost down. In addition, molded parts utilize raw materials more efficiently, thus reducing waste. Depending on the size of the run, and the size and complexity of the part being produced, the cost could be four times as high for machining the parts than it would be for molding them.
As an added benefit, General Plastics’ molded parts are self-skinning, so when the part is released from the mold, the surface will require little, if any, finishing. Paint and texture can also be applied based on customer specifications. “The densified surface of the material results in a nice, shiny finish that closes out the cells and provides added durability sought by many customers,” said Regional Accounting Manager James Overton.
Infinite Applications
Casting or molding rigid polyurethane foam is a process that lends itself well to the production of fuel floats. The need for a smooth rind or skin that is produced from the molding process is necessary in this application as it provides improved resistance, preventing the material from breaking down and absorbing fuel. Through this process, complex shapes and designs can also be achieved.
For functional décor applications, molded foam parts serve building applications such as interior and exterior architectural elements. These can include custom, highly detailed crown moldings and faux-wood shutters. Another example is decorative corbels for a home exterior, and window shutters, which can be molded with a built-in wood-grain texture and easily painted, and lightweight, high-volume props for theaters or movies.
Other applications include hockey sticks as shown in our rigid molded parts video, kayak paddles, and fishing rod handles. All of which are readily molded in high volumes.
Molded Parts for Military and Aerospace Applications
General Plastics manufactures various spacer and void-fill parts that leverage multiple physical properties of foam: high strength-to-weight, flame-retardant, easy shaping, and insulating. Overton explains that pieces are molded to a specific size and shape to fit into a particular area, or can also be part of an assembly.
Other military applications such as dunnage packaging are dense, rigid molded structures with circular slots, similar to a wine rack, for transporting munitions. Depending on the requirements and design, these flame-retardant, impact-absorbing lightweight molded structures can hold their payloads snugly or simply keep them separated from each other within their crates.
Full Spectrum Services
When working with General Plastics and choosing molded parts, customers are not limited to the materials we sell. Beyond our polyurethane foam parts, services also include part and tool design, mold tooling manufacture, machining molded products to create finishing details, applying other finishes and/or incorporating parts in assemblies, depending on what’s required. Our facilities, capabilities, certifications and expertise equip us to manage all aspects of a rigid foam molded program as needed.