Stockwell Elastomerics is a leading producer of liquid silicone rubber (LSR) based products using its extensive in-house silicone rubber molding operations. LSR is a versatile elastomer that can be molded into sheets and cast into steady rolls for die slicing or waterjet reducing.
Stockwell Elastomerics applies acrylic strain sensitive adhesives onto LSR sheets and rolls for adhesive backed gaskets. One of Stockwell Elastomerics’ specialties is applying movie supported acrylic adhesives, akin to 3M 9415 or Adchem 256M and 3M 467 switch movie adhesive onto .010″ and .020″ thick cast liquid silicone rubber for show gaskets and similar functions requiring a very skinny gasket.
Stockwell Elastomerics additionally injection molds customized 3D parts per buyer specifications. LSRs have a large temperature range (-58°F to 392°F) and will be made in extensive durometer vary (10 — 80 Shore A) without plasticizers. Silicone’s glorious rebound, UV and xt_blog (http://freemansears51.xtgem.com/__xt_blog/__xtblog_entry/__xtblog_entry/21711512-what-are-the-advantages-of-silicone-water-mugs-and-also-bottles?__xtblog_block_id=1) ozone resistance makes it ultimate for out of doors sealing and will be use for submerged gaskets (IP67 and NEMA 6). Stockwell Elastomerics maintains in-house inventory of silicone sheet, silicone rolls and molding compounds to be injection molded for fast response instances.
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Rubber Touch Brochure
Consists of small samples of cured LSR supplies to contact and 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 forged into silicone rubber sheets. «Liquid» is specific in the identify to differentiate LSRs from high consistency gum based silicone products (anotepad.com). LSRs are addition cure / platinum cure programs in contrast with most gum based silicones which are peroxide cured. In its raw uncured kind, LSR is 2 elements liquid which are blended collectively (mixing of Part A and Half B starts the curing) and heated to accelerate the curing process. Uncooked gum based mostly silicones look and feel similar to clay. LSRs are usually injection molded or cast while gum primarily based silicones are typically compression molded. Note 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 sizzling mold vs. plastic pellets melted into hot liquid and compelled right into a cooled mold.
Silicone Materials Selection Information
Why Specify Liquid Silicone Rubber?
Performance properties and quick cure cycles make liquid silicone rubber a good alternative for small molded elements. Not like most thermoplastic elastomers (TPRs and TPEs), LSR remains versatile and elastic down to -58°F and retains its properties up to 392°F. Liquid silicone rubber is an efficient candidate for gaskets, seals and cushioning pads in portable communications, data acquisition devices and ruggedized digital units the place out of doors circumstances are demanding. The cure cycles in liquid injection molding permit for a 1 or 2 cavity mold to out-produce a compression mold with a higher cavity count.
Past the mechanical, chemical, and thermal properties of LSR, there are quite a few different reasons to specify this sort of material. From a manufacturability standpoint, a couple of key factors stand out. One in all the most important reasons that prospects might end up going with LSR materials is geometry. Any kind of 3D shape that cannot be fabricated in a flat configuration would require a molding course of — often with parts like this, a excessive manufacturing quantity stage justifies the added value of tooling that’s associated with LSR molding.
Moreover, some prospects may have flat gaskets, however with very tight thickness tolerance wants. In these cases, Stockwell Elastomerics can leverage its sheet molding capabilities to carry tighter tolerances in small sheets, which may then be used to die-lower or waterjet cut flat gaskets and pads.
Transitioning from Flat Prototypes to Molded Manufacturing Components
Once in a while, prospects need to transition from flat minimize elements to molded parts. As clients work by means of small prototype runs of initial designs, Stockwell Elastomerics helps this alteration with quick flip waterjet lower gaskets using molded LSR sheets. As designs develop and molding is required, the identical material may be utilized. This eliminates re-testing and re-validation, since the fabric is the very same for the prototypes and production elements.
For elements without any type of 3D geometry, molding might be a very value efficient resolution at excessive quantity production, as conventional die-reducing and waterjet slicing have wasted material price. For instance, a small window gasket could also be quite value effective to provide in small portions as a waterjet lower half, however as production quantities improve, the combined price of the wasted window cutout can add up. In cases like this, paying to device-up a manufacturing LSR mold creates a way more cost-efficient resolution trimmed piece value down the line.
Cure Catalysts — Tin vs. Platinum
In LSR materials, a catalyst is required as part of the curing course of. Widespread cure catalysts are tin (often known as condensation cure) and platinum (often known as addition cure). All of Stockwell Elastomerics’ LSR products are platinum-cured.
Platinum-cured LSR is usually «cleaner» than tin-cured LSR — because of this a lot of Stockwell Elastomerics’ LSR products are suitable for use in the medical machine trade. Platinum-cured LSR is often capable of meeting FDA and USP Class VI certifications. Platinum-cured LSR may survive higher temperatures when in comparison with tin-cured alternate options.
Tin-cured LSR is usually found in client and inventor-grade material. This materials can cure using condensation from the air and does not require heat. Tin-cured LSR is usually not FDA grade and isn’t used in more demanding purposes.
While tin-cured LSR is extra accessible for interest-grade and varied consumer purposes, it does not provide among the distinct benefits and excessive-performance traits of platinum-cured LSR. That is why platinum-cured LSRs used solely — these materials best serve prospects in core industries served by Stockwell Elastomerics.
Liquid Silicone Durometer Range
LSR is out there in a hardness range of 10 to 80 durometer Shore A. 10 durometer LSR could be very delicate like chewing gum and might feel softer than some additional agency silicone foam and silicone sponge products. 80 durometer LSR is tougher than a heel of a shoe and is as firm as many thermoplastic elastomer products. Most functions for LSR are specified within the 20 to 60 durometer Shore A variety.
Stockwell Elastomerics’ Liquid Silicone Rubber Touch Brochure can assist with selection of fabric hardness for particular functions. The tensile, elongation and tear resistance properties of liquid silicones have improved since the initial commercialization of LSR.
Liquid Silicone Rubber Availability
Stockwell Elastomerics provides off-the-shelf LSR sheets (12″ x 12″) and steady solid rolls with or without film supported acrylic or acrylic transfer film adhesive options. The 12″ x 12″ molded sheets are available from .032″ to .125″ thick. Stockwell Elastomerics’ on-site molding facility offers molded and cryogenically deflashed, custom liquid silicone gaskets and a variety of customized parts.