Rubber Injection Molding

Rubber Injection Molding2018-10-30T09:59:00+00:00

Rubber Injection Molding

The Custom Rubber Injection Molding Experts

With over thirty years of experience with rubber injection molding, Qualiform offers competitive pricing combined with unparalleled product quality and service.  Qualiform Rubber Molding is a leading provider of rubber injection molding to OEMs across the US.  OEMs rely on our expertise in material properties and rubber compound selection, design consultation and complex part molding.

Qualiform is certified to ISO 9001:2015 and experienced in meeting the strictest quality standards.

Rubber Injection Molding

Rubber injection molding is used to develop both solid rubber parts and rubber-to-metal bonded products.  Natural and synthetic rubber compounds can provide a wide variety of properties that solve problems from seals or gaskets, noise and vibration isolation, abrasion and impact resistance and chemical/corrosion resistance.  Rubber injection molding is an ideally suited for mid-to-high-volume production and where tight tolerances, part consistency or over-molding are required.  In addition, rubber injection molding works well with rubber compounds that have faster cure times.  This is a process that can be fully automated.

The Rubber Injection Molding Process

Rubber injection molding was first used in the mid-1960s and was based on the plastic injection molding process.  The key difference between plastic and rubber injection molding is that in rubber requires significantly higher pressure to cure the rubber thus leading to longer cure times.

The process starts with the tooling, a rubber injection mold typically with multiple cavities.  The mold consists of a nozzle plate, runner plate, cavity plate, and a base plate with a post-molding ejector system.  The rubber compounds and additives are mixed to create rubber stock.  The stock is formed into continuous strips of uncured rubber stock approximately 1.25″ wide & .375″.

The continuous strip is automatically fed from a hopper into the injection molding machine into a heated barrel, conveyance channel, which softens, plasticizes the rubber.  The stock is then pushed by a large auger, screw-type plunger through the injection nozzle. After flowing into the nozzle plate, the rubber is routed through the runner plate, through the gates, and then into the mold cavities.

When the cavities have been filled the heated mold is kept closed under pressure. The temperature and pressure activate the cure of the rubber compound, vulcanizing it.  Once the rubber reaches and required level of cure, it is allowed to cool and reach a solid state within the mold. The molds open and parts are removed or ejected and ready for the next cycle.

In cases where rubber injection molding is used to encapsulate metal components with rubber or bond rubber to metal, the components are loaded, either by hand or using a loading fixture, into the heated mold cavities. The mold is then closed and the injection molding cycle can begin. After curing is completed, the mold is opened and parts are removed. The cured rubber in the runner is removed, cured rubber in the injection nozzle is purged, and the mold cavities are cleaned in preparation for the next molding cycle.

Rubber Injection Molding Advantages

  • A mid-to-high volume, efficient process
  • Full automation is available
  • Provides high-tolerance, precision rubber molded products
  • The best rubber process for consistency and repeatability
  • Allows for molding of complex geometry
  • Ideal for rubber to metal bonding,  insert molding and over-molding
  • Color molded rubber
  • Lower unit cost
  • Eliminates preforms and preform labor cost
  • Flashless molding / flashless tooling / eliminating secondary trimming
  • Rapid cavity filling
  • Reduced cycle time
  • Minimal material waste

Rubber Injection Molding Disadvantages

  • Higher start-up/shutdown costs
  • Suited for high volume applications
  • Not all elastomers are suitable due to fast cure times

Typical Parts Produced with Rubber Injection Molding

  • Rubber boots
  • Rubber gaskets
  • Rubber seals
  • Rubber grommets
  • Colored rubber products
  • Rubber bumpers
  • Rubber grips
  • Rubber diaphragms
  • Rubber bellows
  • Rubber shock absorbers
  • Rubber to metal bonding products
  • Complex rubber products
  • Vibration control parts / vibration isolation parts
  • Chemical or corrosion resistant parts
  • Abrasion-resistant parts
  • Custom rubber parts

Materials We Process

  • Butyl
  • SBR
  • Natural Rubber
  • Silicone
  • Colored Compounds
  • EPDM
  • Nitrile
  • Viton©
  • Neoprene

Rubber Molding Capabilities

Different molding processes have different strengths.  That’s why Qualiform offers quality custom rubber compression molding, custom transfer molding, custom rubber injection molding, and rubber to metal bonding .  Our experts help you match the best process to your project.

Our technical staff is available to answer any questions call (330) 336-6777, or submit a question / inquiry through our Contact Form or Send Us a PDF.

Custom Injection Molding

Our technical staff is ready to assist you with all your custom rubber injection molding needs.

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