Produce Polyurethane Parts Using Reaction Injection Molding

Reaction Injection Molding (RIM) being part of the business for over 20 years now, it has emerged as a popular method of producing premium quality molded polyurethane parts. You can find a number of reaction injection molding factory which produces variety of RIM range from simple parts to complicated structural components typically in volumes of one to 5,000 pieces. RIM polyurethane parts are produced for a wide variety of industries, including medical, computers, business machines, telecommunications and graphic imaging.

Two-part, low-viscosity urethane systems are easily processed and are available in a variety of hardness and stiffness ranges. The urethane systems is quite common in the system as the urethanes reproduce fine details and these are dimensionally stable, chemical resistant, physically tough and wear resistant. You can even find reaction injection molding factory with flame retardant grades with UL 94 VO and 5V made available for various requirements. Considerable design freedom is possible with thick and thin wall sections due to the uniform shrink characteristics.

The foamed polyurethanes are natural thermal and acoustic insulators controlled by adjusting the molded part density and choice of material system. Also the excellent flowability allows the encapsulation of inserts. There are two broad categories used in plastic materials, i.e, Thermoplastics and Thermosets.

Thermoplastics is a soft material which can be melted melt when heated and harden when cooled, allowing the use of injection molding, thermoforming, extrusion, and other processing techniques. Thermosets on the other side is formed by chemical bonds between adjacent polymer molecules, called crosslinking. The system of polymer chains tends to degrade instead of softening when heated extremely. Recent advances in recycling techniques have allowed breakdown and reuse of some base components since they do not melt, thermosets must be processed differently.

RIM molded polyurethanes require a controlled chemical reaction within the mold. Not only is a part made but the plastic material is also created as the mold becomes the polymerization reaction vessel with components impinged in a mix head as they enter. These parts require more secondary finishing than thermoplastics but they usually shrink less and exhibit much better thermal and chemical resistance.

Polyurethanes moreover can be broken down into two groups:

1. 1. Elastomeric or flexible systems: This ranges from almost rigid high modulus impact-resistant materials to super-soft and flexible polymers
2. 2. Rigid materials: This consists of flexural modulus and hardness up to glass-like and very brittle materials.

Since a properly cooled aluminum mold is best able to control the heat of reaction during the molding process, aluminum must be used when maximum physical properties of the urethane material system are required. Aluminum does not allow exotherm overrun and hot spot induced internal stresses. When dimensional accuracy is critical and production quantities are high, machined aluminum is the logical choice.

There are ample amounts of reaction injection molding factory those produces RIM with low internal mold pressure generated during the process. Resin molds are used for components requiring more detail and better physical properties. Foamed urethane systems can be processed in these urethane and epoxy resin molds. Silicone rubber can be quite successful when used for very low quantities of dimensionally non-critical parts.

Honkia Prototype is a Rapid Prototyping and Low Volume Production factory that specializes in Sla/Sls, Cnc Machining, Vacuum Casting, Reaction Injection Molding and Sheet Metal Fabrication.