A better reaction to your design.
In general, reaction injection molding allows for superior design in polyurethane parts – over injection molding, thermoforming, and cast molding – when you require:
- Low cost tooling
- Large parts
- Variable part wall thickness
- Molded in bosses, ribs, inserts, tabs, undercuts
- Flexible cosmetic surface and part design
- Encapsulation capabilities
- Dimensional stability
- Chemical resistance
- In-mold painting and post-paint
We help you choose the system that best matches your design.
The range of polyurethane systems that reaction injection molding allows means you can achieve your ideal characteristics of:
- Impact resistance
- Dimensional stability and strength
- Design tolerance
- Wear- and corrosion-resistance
- Thermal insulation
- Electrical non-conduction
- Sound absorption
- Natural adhesion
RIM Manufacturing will help you choose what is best for your parts from these systems:
Elastomeric – for parts with superior impact strength, durability, dimensional stability and resistance to corrosion, abrasion and wear.
Solid – produces parts similar to those created with thermoplastic systems, but these allow variation of wall thickness throughout a part without visible sink marks. Typically, minimum wall thickness is 1/8” to 1/2”.
Rigid Foam – a blowing agent creates a high-density skin around a low-density microcellular core. The skin gives the part firmness and durability while the core reduces weight. Wall thickness can vary from 1?4” to 11?2”.
Flexible Foam – this system’s blowing agents create self-skinning foams. The thickness of the skin and density of the foams can be adjusted to achieve the precise flexibility, firmness and support characteristics your parts require.
Reinforced RIM (RRIM) – the Elastomeric system with glass or mineral fillers introduced to produce parts with greater rigidity.
Structural RIM (SRIM) – Solid or Foam chemistries can incorporate long-fiber reinforcements, like glass mats, to increase stiffness and impact resistance.
Design factors to consider.
RIM Manufacturing will work with you to maximize your part’s design by making the ideal choice from the wide array of manufacturing chemistries and systems we offer. Together we’ll consider:
- The part’s purpose
- Structural, impact and load requirements
- Environmental conditions the part will be subjected to
- Chemicals the part will be exposed to
- Special design requirements to be considered
- Aesthetic requirements
- Weight requirements
- Particular finish, color or paint requirements
- Cost-reduction opportunities
Then we’ll work with you to enhance the part’s design specifications:
Wall thickness and strength – we select the right system and chemistry to achieve the optimal cross section for cycle time, output, and cost.
Ribs – usually running the length of a part, ribs can also be bidirectional to allow for thinner walls, greater strength, warp reduction, and lower cost when faster cooling reduces cycle time.
Draft – considered in every surface parallel to the direction of the draw, draft angle increases with part height. This is an especially important consideration for the core side of the mold since the part shrinks onto the cavity as it cools. With RIM Manufacturing, drafts can be as slight as 1°.
Bosses – frequently incorporated to accommodate threaded inserts, their primary benefit is allowing air to escape during molding and optimizing cycle time. This is generally most successful with bosses in side walls or gussets added to isolated gussets.
Holes, grooves, and vents – these features, oriented in the direction of the chemical flow, can enhance injection into the mold by reducing stress concentration, air entrapment and knit lines, especially rounded or chamfered grooves. Usually created by hand-loaded inserts or hydraulic inserts, the incorporation of holes and grooves is sometimes more cost-effective when they are drilled.