Stockwell Elastomerics is a leading producer of liquid silicone rubber (LSR) based products using its intensive in-house silicone rubber molding operations. LSR is a versatile elastomer that can be molded into sheets and forged into steady rolls for die cutting or waterjet cutting.
Stockwell Elastomerics applies acrylic strain sensitive adhesives onto LSR sheets and rolls for adhesive backed gaskets. Considered one of Stockwell Elastomerics’ specialties is making use of film supported acrylic adhesives, corresponding to 3M 9415 or Adchem 256M and 3M 467 transfer movie adhesive onto .010″ and .020″ thick forged liquid silicone rubber for display gaskets and related applications requiring a very thin gasket.
Stockwell Elastomerics also injection molds custom 3D parts per customer specs. LSRs have a large temperature vary (-58°F to 392°F) and will be made in wide durometer range (10 — eighty Shore A) without plasticizers. Silicone’s glorious rebound, UV and ozone resistance makes it best for outside sealing and may be use for submerged gaskets (IP67 and NEMA 6). Stockwell Elastomerics maintains in-house stock of silicone sheet, silicone rolls and molding compounds to be injection molded for quick response times.
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What is Liquid Silicone Rubber?
Liquid silicone rubber (LSR) is very low viscosity silicone that may be injection molded or forged into silicone rubber sheets. «Liquid» is specific in the title to differentiate LSRs from high consistency gum primarily based silicone products. LSRs are addition cure / platinum cure techniques in contrast with most gum based silicones which can be peroxide cured. In its uncooked uncured form, LSR is two components liquid which are blended together (mixing of Half A and Part B begins the curing) and heated to accelerate the curing process. Uncooked gum based silicones look and feel just like clay. LSRs are generally injection molded or forged while 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 hot mold vs. plastic pellets melted into hot liquid and silicone mold cheap compelled right into a cooled mold.
Silicone Materials Selection Guide
Why Specify Liquid Silicone Rubber?
Performance properties and fast cure cycles make liquid silicone rubber a good choice for small molded parts. Unlike most thermoplastic elastomers (TPRs and TPEs), LSR stays 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 electronic devices the place out of doors situations are demanding. The cure cycles in liquid injection molding enable for a 1 or 2 cavity mold to out-produce a compression mold with a better cavity depend.
Past the mechanical, chemical, and thermal properties of LSR, there are quite a few different reasons to specify this type of material. From a manufacturability standpoint, just a few key factors stand out. One of the largest causes that prospects might find yourself going with LSR materials is geometry. Any kind of 3D form that cannot be fabricated in a flat configuration would require a molding process — usually with elements like this, a excessive manufacturing quantity stage justifies the added price of tooling that is associated with LSR molding.
Moreover, some customers could have flat gaskets, but with very tight thickness tolerance wants. In these cases, Stockwell Elastomerics can leverage its sheet molding capabilities to hold tighter tolerances in small sheets, which may then be used to die-reduce or waterjet reduce flat gaskets and pads.
Transitioning from Flat Prototypes to Molded Production Parts
Now and again, clients want to transition from flat reduce elements to molded parts. As clients work through small prototype runs of initial designs, Stockwell Elastomerics helps this variation with fast turn waterjet lower gaskets using molded LSR sheets. As designs develop and molding is required, the identical materials can be utilized. This eliminates re-testing and re-validation, since the material is the exact same for the prototypes and manufacturing components.
For components with none kind of 3D geometry, molding may be a really cost effective answer at excessive amount manufacturing, as conventional die-cutting and waterjet cutting have wasted material value. For example, a small window gasket could also be quite cost effective to provide in small portions as a waterjet cut half, however as production portions enhance, the mixed value of the wasted window cutout can add up. In circumstances like this, paying to software-up a manufacturing LSR mold creates a much more value-efficient solution trimmed piece value down the line.
Cure Catalysts — Tin vs. Platinum
In LSR materials, a catalyst is required as a part of the curing course of. If you beloved this article and you would like to receive more info with regards to silicone mold cheap nicely visit the page. Frequent cure catalysts are tin (also referred to as condensation cure) and platinum (also called addition cure). All of Stockwell Elastomerics’ LSR merchandise are platinum-cured.
Platinum-cured LSR is usually «cleaner» than tin-cured LSR — because of this a lot of Stockwell Elastomerics’ LSR merchandise are appropriate for use in the medical system business. Platinum-cured LSR is often able to assembly FDA and USP Class VI certifications. Platinum-cured LSR also can survive greater temperatures when in comparison with tin-cured options.
Tin-cured LSR is often found in shopper and inventor-grade materials. This material can cure using condensation from the air and does not require heat. Tin-cured LSR is often not FDA grade and isn’t used in more demanding applications.
While tin-cured LSR is more accessible for passion-grade and various consumer applications, it doesn’t supply among the distinct advantages and high-performance traits of platinum-cured LSR. That is why platinum-cured LSRs used completely — these materials greatest serve prospects in core industries served by Stockwell Elastomerics.
Liquid Silicone Durometer Range
LSR is obtainable in a hardness range of 10 to 80 durometer Shore A. 10 durometer LSR may be very gentle like chewing gum and might really feel softer than some extra firm silicone foam and silicone sponge merchandise. 80 durometer LSR is more durable than a heel of a shoe and is as agency as many thermoplastic elastomer products. Most purposes for LSR are specified in the 20 to 60 durometer Shore A variety.
Stockwell Elastomerics’ Liquid Silicone Rubber Contact Brochure can assist with selection of material hardness for particular applications. The tensile, elongation and tear resistance properties of liquid silicones have improved since the initial commercialization of LSR.
Liquid Silicone Rubber Availability
Stockwell Elastomerics offers off-the-shelf LSR sheets (12″ x 12″) and continuous solid rolls with or without movie 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 gives molded and cryogenically deflashed, customized liquid silicone gaskets and quite a lot of customized elements.