TPE Injection Molding – Thermoplastic Elastomers
Flexible thermoplastic elastomers are molded with plastic injection molding with Rebling for a wide range of applications. The ability of these thermoplastic materials to be processed by conventional plastic injection molding machines and their inherently short cycle times compared to the cure time of thermosetting rubbers has provided engineers and designers with a cheaper alternative when defining flexible plastics. In addition, there are standard compounds that provide mechanical properties, hardness, chemical resistance and elasticity that are not available with thermosetting rubber.
Molds for thermoplastic elastomers or TPE injection molding parts such as cable strain reliefs, over-casting of handles or other components, airplane helmets and medical devices.
Properties Of Thermoplastic Elastomers – TPE injection molding
The TPE injection molding is available in durometers which are generally between 30 and 95 on the Shore A hardness scale, depending on the class of material selected.
These flexible resources, commonly referred to as TPRs or TPEs, typically fall into four classes of thermoplastic materials: polyester copolymers olefin; polyurethane; and styrene block copolymers. PVC is another option for flexible thermoplastic materials.
Two types of styrene elastomers are available for plastic injection molding. The styrene-ethylene / butylene-styrene (SEBS) block and the styrene-butadiene-styrene (SBS) block. Trade names for these materials include KRATON® D and KRATON® G. Elastomers of the SEBS block have higher temperature resistance and resistance to longer outdoor exposure, while the SBS block should be restricted to indoor applications. Both types are resistant to water, acids, and bases, but are both attacked by solvents. Both types can be formatted in different colors.
Polyurethanes are known for their excellent abrasion resistance and load-bearing capacity. Polyester, polyether, and polycaprolactone based urethane grades work well in the plastic injection molding process. Polyester types have better mechanical properties, while polyether types have improved low-temperature properties and hydrolysis resistance. The polycaprolactone group offers better hydrolysis resistance than polyester-based urethanes while providing similar mechanical properties.
All urethane can be molded in a wide range of colors and is available in a variety of grades for special applications including flame-retardant materials.
Olefins have the lowest density of all thermoplastic elastomers. DuPont Engage® is an example of this material that is available in pure and color quality. Olefinic offers excellent flexibility at temperatures as low as -60 ° F.
Polyester copolymers provide flexibility and fatigue over a wide temperature range. DuPont Hytrel® is an example of this type of elastomer. This group is generally priced higher than olefin and styrene-based elastomers.
Guide To Thermoplastic Elastomers
Authorized design engineers have extensive experience in optimizing the design of plastic parts in terms of functionality, cosmetics, cost, and processing. As with other thermoplastic materials, the preservation of the entire wall thickness is essential for the production of aesthetically pleasing castings. Ribs and inserts must be used to prick thick sections. The thickness of the ribs shall not exceed 50% of the wall thickness. Built-in bosses can also produce sinking signals if not properly designed. In order to minimize and eliminate these issues, construction engineers should be consulted before the final plan is issued. This design planning is provided free of charge.
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