Reaction Injection Molding (RIM) vs Other Processes

Comparison gives us a very positive reaction.

Reaction injection molding has many benefits: low tooling costs, short lead-times, large lightweight parts, high tolerances, enhanced design finish, desired chemical resistance properties, 94V-0 and HB ratings, customizing part properties, and molding over metal, wood, glass, computer chips and other parts.

Reaction injection molding is generally most cost-effective for the production of a few hundred to several thousand parts, but one RIM Manufacturing client has looked to us to produce more than 1,000,000 parts per year for 10 years.

RIM Process VS. Injection Molding

RIM Process Advantages

Large, lightweight parts
Varying wall thickness with no sink
Deep draw
Can combine multiple designed parts into one part within a single mold
Low-to-moderate cost tooling – machined aluminum
Short lead-time
Tooling can be used for prototype and easily modified for production parts
Material flexibility – elastomers, solid RIM, structural foam, flexible foam, DCPD, etc.
Encapsulation of component materials including metals, electronics, plastic, valves, circuitry, etc.
Low-to-high production volume
Tight tolerances

Injection Molding

Small-to-mid size parts
Requires uniform wall thickness
Limited draw
Multiple mid-size parts generally require multiple molds
High-cost tooling – steel
Long lead-time
Prototypes require different tooling and tooling modifications are expensive
Limited material options
Limited encapsulation
Moderate-to-high production volume
Tight tolerances

RIM Process VS. Thermoforming & Vacuum Forming

RIM Process Advantages

Complex geometry and cosmetically appealing parts
Deep draw with structural integrity
Varied wall thickness throughout the part
Structural integrity molded into parts
Molded-in attachment points
Tight tolerances
Low-to-moderate cost tooling
Low-to-moderate production
Material flexibility – elastomers, solid RIM, structural foam, flexible foam, DCPD
Encapsulation of component materials including metals, electronics, plastic, valves, circuitry, etc.

Thermoforming & Vacuum Forming

Simple part design and geometry
Draw limited and requires post-molding structural features
Requires uniform wall thickness
Post-molding gluing of ribs
Glued attachment points
Low-to-moderate cost tooling
Limited material flexibility
No encapsulation capability

RIM Process VS. CAST Molding

RIM Process Advantages

Cosmetically appealing parts right out of the mold
Prototype tooling can be used for production parts
Tight consistent part tolerances
Variable wall thickness without sink
Tooling lasts the lifetime of the project
Short lead-time on tooling

Cast Molding

Cosmetic inconsistencies of parts off the mold
Prototype and production tooling are different
Part tolerance varies from part to part
Variable wall thickness generally includes sink
Short lead-time on tooling

RIM Process VS. Sheet Metal

RIM Process Advantages

Tremendous design flexibility
Large and light-weight parts
Structurally strong and durable
Molding in color an in-mold painting
Variable wall thickness within the same part
Affordable part cost
Capable of combining multiple parts into one integrated part
Provide sound and vibration insulation
Corrosion and rust-resistant
Part cost is more stable

Sheet Metal

Limited design flexibility
Parts are heavy
Post-painting required
High part cost
Varied wall thickness requires welding multiple parts
Multiple parts require labor and assembly costs
Structurally stronger parts
Part pricing is less stable due to the commodity’s market

RIM Process VS. Die Casting

RIM Process Advantages

Lower weight
Higher tolerances
Greater design freedom
No brittle parts
Net shape with no machining
Corrosion-resistance

Die Casting

Low tooling cost
Shorter lead-time