Molding Processes

Plastic Molding Processes



Since our founding in 1962, we've offered many types of plastic molding processes to meet our Customers’ diverse needs including thermoplastic injection molding, insert molding, wire over-molding, thermoset injection, compression, and transfer molding. No matter the process, we can recommend and manufacture plastic parts in the appropriate material for any project.

We produce custom-molded plastic parts for OEMs in the Defense, Avionics, Instrumentation, Medical, Consumer Products, Energy, and Transportation industries. ISO 9001 certified ITAR Registered, DoD Certified Munitions Supplier, QPL Approved, FDA Class I, II, and III medical devices. The parts we create range from dime-sized to gallon-sized, from parts designed to last 50 years to those designed as disposables, in quantities from 500 pieces to 20,000,000 pieces per year, and for environments as pleasant as an air-conditioned office to as unforgiving as an oil drilling borehole.

We produce thermoplastic and thermoset custom molded parts using hundreds of different standard and custom plastic formulations (see alphabetical listing below) and offer a wide spectrum of insert-molding (plastic molded around metal parts), over-molding (plastic molded around plastic parts), and post-molding services (machining, assembly, printing, laser marking, ultrasonic welding, heat staking, etc). We specialize in a wide spectrum of molding services, including insert molding and over-molding services. 95% of the parts we produce are smaller in size than a gallon jug of milk, weigh less than one pound, and have a maximum dimension shorter than 12 inches.

Whether you have a drawing, a sample, or simply an idea, our team can design the part and select the material which best fits your needs, perform 3D modeling, create full-size prototypes, design and create the molds, perform first article inspection and then produce production quantities. We are ITAR registered and ISO 9001 certified.

Injection Molding

The most common way to produce plastic parts is via the injection molding process. When the process uses raw materials that can be heated to soften or melt, it is called thermoplastic injection molding. Many plastic parts are made from thermoplastic materials including Nylon, Polycarbonate, and ABS. When the process uses materials that permanently solidify through a chemical reaction, it is called thermoset molding. Thermoplastic injection molding, which relies on the rapid cooling of the melted plastic material inside the mold, typically results in a much faster processing cycle than thermoset molding. Typical thermoset materials include DAP, Phenolic, and Epoxy.

Thermoset materials are typically used in applications where retention of mechanical properties at extremely elevated temperatures is a requirement. The thermoset manufacturing process requires significant experience with plastic injection molding. Whether using thermoplastic or thermoset material, injection molding is the most cost-effective method because it can be automated, eliminating labor-intensive preliminary or secondary operations.

Insert Molding

One specialized type of plastic injection molding performed at Rebling is called insert molding. This process involves molding plastic around another part, which could be made of metal or another plastic material. Wire over-molding, or wire plastic molding, is a special type of insert molding where plastic is molded over different sizes of wires to form a plug or strain relief.

Thermoset Transfer Molding and Compression Molding

The Thermoset Transfer molding process starts with pre-forming a cylindrical “pill” of material of the proper weight. The pill is usually hand loaded into a mold, where a plunger pushes the material into the cavity, and the thermoset material cures, through a chemical reaction, under heat and pressure.

Thermoset Compression molding uses a loose, powdery molding material that must be weighed before an operator or automated equipment places the material into an open mold cavity. The press applies heat and pressure until the part is cured.

While both of these methods are more labor-intensive than injection molding, some thermoset materials are only available in transfer and compression grades. In order to achieve some of the special properties of thermoset materials, compression and transfer molding processes are sometimes necessary.

Consistent Processing

No matter which molding method is used, processing parameters for each part are documented and stored in machine memory to insure lot-to-lot consistency.

Using modern, state-of-the-art primary and auxiliary processing equipment enables Rebling to provide the highest quality molded parts available anywhere. To ensure part consistency and minimize machine downtime, all processing equipment is serviced using an extensive preventative maintenance program. This includes all the Customer-owned molds and fixtures which undergo routine maintenance during and after production runs. Every mold is tracked for a number of cycles in our ERP system to ensure maintenance is performed at the proper interval.