Plastic Molding Processes
At Rebling Plastics, we perform several types
of plastic molding processes to meet our customers’
diverse needs. We have decades of experience with
thermoplastic injection molding, insert molding
(including wire overmolding), and thermoset injection,
compression and transfer molding. No matter what
the process, we feel that we can recommend and
manufacture plastic parts out of an appropriate
material for almost any project.
Plastic Injection Molding
The most common way to produce plastic parts
is the plastic injection molding process. When
the process uses materials that can be heated
to soften or melt, it is called thermoplastic
injection molding. Most plastic parts today
are made from thermoplastic materials such as
nylon, and ABS.
When the process uses materials that permanently
solidify by a chemical reaction, it is called
thermoset injection
molding. Thermoplastic injection molding,
which relies on the rapid cooling of the plastic
melt in the mold, typically results in a much
faster process cycle than thermoset molding.
The principal thermoset materials molded by Rebling
Plastics are DAP, phenolic
and epoxy.
Thermoset materials are typically used in specialized applications where retention of mechanical properties at elevated temperatures is a requirement. Using either type of material, plastic injection molding is the most cost effective method for manufacturing at Rebling Plastics, because it can be automated, and it does not require any labor intensive preliminary or secondary operations.
One specialized type of plastic injection molding
performed at Rebling Plastics is called insert
molding. This process involves molding plastic
around another part, which could be made of metal
or another plastic material. Wire
overmolding is a special type of insert molding
where plastic can be molded over different sizes
of wires to form a plug or strain relief. Rebling
Plastics has experience with wire overmolding
several types of parts using a variety of wire
sizes.
The thermoset transfer molding process starts with pre-forming a cylindrical “pill” of material at 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 under heat and pressure.
Thermoset compression molding uses a loose bulk molding compound 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 plastic 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. That is why Rebling Plastics
is committed to offering all types of thermoset
molding to our customers.
Consistent Processing
No matter which molding method is used, processing parameters for each part are documented (or stored in machine memory) to insure lot to lot consistency.
Using modern, state of the art primary
and auxiliary processing equipment enables
Rebling Plastics to provide the highest quality
plastic moldings available in the industry today.
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.
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