Stockwell Elastomerics is a number one manufacturer of liquid silicone rubber (LSR) based products utilizing its extensive in-house silicone rubber molding operations. LSR is a versatile elastomer that can be molded into sheets and cast into continuous rolls for die reducing or waterjet reducing.
Stockwell Elastomerics applies acrylic stress sensitive adhesives onto LSR sheets and rolls for adhesive backed gaskets. One in all Stockwell Elastomerics’ specialties is making use of film supported acrylic adhesives, akin to 3M 9415 or Adchem 256M and 3M 467 switch movie adhesive onto .010″ and .020″ thick forged liquid silicone rubber for show gaskets and comparable applications requiring a very skinny gasket.
Stockwell Elastomerics additionally injection molds custom 3D parts per buyer specifications. LSRs have a large temperature vary (-58°F to 392°F) and could be made in broad durometer range (10 – eighty Shore A) with out plasticizers. Silicone’s wonderful rebound, UV and ozone resistance makes it ideally suited for outdoor sealing and will be use for submerged gaskets (IP67 and NEMA 6). Stockwell Elastomerics maintains in-home stock of silicone sheet, silicone rolls and molding compounds to be injection molded for quick response times.
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Rubber Contact Brochure
Contains small samples of cured LSR supplies to touch and really feel.
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What is Liquid Silicone Rubber?
Liquid silicone rubber (LSR) could be very low viscosity silicone that can be injection molded or cast into silicone rubber sheets. “Liquid” is express within the name to differentiate LSRs from high consistency gum primarily based silicone merchandise. LSRs are addition cure / platinum cure systems in distinction with most gum based silicones which can be peroxide cured. In its uncooked uncured form, LSR is 2 parts liquid which are mixed together (mixing of Half A and Half B begins the curing) and heated to accelerate the curing process. Uncooked gum based mostly silicones appear and feel similar to clay. LSRs are typically injection molded or cast whereas gum primarily based silicones are sometimes compression molded. Notice that injection molding of liquid silicone rubber is the inverse of molding thermoplastics; room temperature liquid silicone compound is injected into and cured in a scorching mold vs. plastic pellets melted into scorching liquid and pressured into a cooled mold.
Silicone Supplies Selection Guide
Why Specify Liquid Silicone Rubber?
Performance properties and quick cure cycles make liquid silicone rubber a great choice for small molded parts. In contrast to most thermoplastic elastomers (TPRs and TPEs), LSR remains versatile and elastic all the way down to -58°F and retains its properties up to 392°F. Liquid silicone rubber is a good candidate for gaskets, seals and cushioning pads in portable communications, knowledge acquisition instruments and ruggedized digital units where outside situations are demanding. The cure cycles in liquid injection molding permit for a 1 or 2 cavity mold to out-produce a compression mold with the next cavity depend.
Past the mechanical, chemical, and thermal properties of LSR, there are numerous different causes to specify this kind of fabric. From a manufacturability standpoint, a couple of key elements stand out. One in all the biggest causes that clients could end up going with LSR material is geometry. Any form of 3D shape that can’t be fabricated in a flat configuration would require a molding process – usually with components like this, a excessive manufacturing amount degree justifies the added price of tooling that’s associated with LSR molding.
Additionally, some prospects might have flat gaskets, however with very tight thickness tolerance wants. In these instances, Stockwell Elastomerics can leverage its sheet molding capabilities to hold tighter tolerances in small sheets, which can then be used to die-cut or waterjet lower flat gaskets and pads.
Transitioning from Flat Prototypes to Molded Production Components
Every now and then, customers wish to transition from flat cut parts to molded parts. As customers work through small prototype runs of preliminary designs, Stockwell Elastomerics supports this change with quick flip waterjet cut gaskets using molded LSR sheets. As designs develop and molding is required, the identical materials may be utilized. This eliminates re-testing and re-validation, since the fabric is the exact same for the prototypes and production elements.
For parts without any type of 3D geometry, molding could be a very price efficient answer at high quantity manufacturing, as conventional die-chopping and waterjet reducing have wasted material value. For instance, a small window gasket could also be fairly cost efficient to supply in small portions as a waterjet cut part, but as manufacturing portions increase, the mixed value of the wasted window cutout can add up. In circumstances like this, paying to software-up a production LSR mold creates a much more value-efficient resolution trimmed piece worth down the line.
Cure Catalysts – Tin vs. Platinum
In LSR materials, a catalyst is required as part of the curing course of. Frequent cure catalysts are tin (also called condensation cure) and platinum (also known as addition cure). All of Stockwell Elastomerics’ LSR merchandise are platinum-cured.
Platinum-cured LSR is usually “cleaner” than tin-cured LSR – this is the reason a lot of Stockwell Elastomerics’ LSR products are suitable to be used within the medical machine business. Platinum-cured LSR is often capable of meeting FDA and USP Class VI certifications. Platinum-cured LSR can also survive increased temperatures when in comparison with tin-cured alternate options.
Tin-cured LSR is often found in consumer and inventor-grade materials. This materials can cure utilizing condensation from the air and doesn’t require heat. Tin-cured LSR is typically not FDA grade and isn’t used in additional demanding applications.
While tin-cured LSR is more accessible for pastime-grade and varied client functions, it does not offer some of the distinct benefits and high-performance traits of platinum-cured LSR. Because of this platinum-cured LSRs used solely – these supplies finest serve clients in core industries served by Stockwell Elastomerics.
Liquid Silicone Durometer Vary
LSR is obtainable in a hardness range of 10 to eighty durometer Shore A. 10 durometer LSR may be very gentle like chewing gum and may really feel softer than some extra agency silicone foam and silicone sponge merchandise. 80 durometer LSR is harder than a heel of a shoe and is as firm as many thermoplastic elastomer products. Most applications for LSR are specified in the 20 to 60 durometer Shore A variety.
Stockwell Elastomerics’ Liquid Silicone Rubber Contact Brochure can help with selection of material hardness for particular applications. The tensile, elongation and tear resistance properties of liquid silicones have improved since the preliminary commercialization of LSR.
Liquid Silicone Rubber Availability
Stockwell Elastomerics gives off-the-shelf LSR sheets (12″ x 12″) and steady cast rolls with or without movie supported acrylic or acrylic switch movie adhesive options. The 12″ x 12″ molded sheets can be found from .032″ to .125″ thick. Stockwell Elastomerics’ on-site molding facility offers molded and cryogenically deflashed, custom liquid silicone gaskets and a wide range of custom parts.
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