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Cable Protectors

Reaction Injection Molding (R.I.M.) vs. Solid-Cast Polyurethane: Why Manufacturing Method Matters


With so many cable ramps available on the market, understanding the difference between manufacturing processes and materials used is critical in making a smart investment decision for your cable protection needs.

Reaction Injection Molding (R.I.M.)

Reaction Injection Molding working plant diagram
Reaction Injection Molding working plant diagram. Image by

Reaction Injection Molding (R.I.M.) occurs when two compounds are thrust into a single mold to create an exothermic, or heat-producing, chemical reaction that cools into homogenous cured material. The resulting products are strong yet lightweight, making them excellent for use in light-duty industrial applications. Think automobile bumpers, dashboards and armrests.

While this method is a popular production process due to the ease of production, reduction in raw material use, lower temperatures and lower mold pressure than regular injection molding, it’s unfortunately not a good choice for heavy-duty industrial applications as the products don’t have the strength and resistance for which solid-cast products are known.

One reason for that is that with R.I.M. there is a potential for trapped gas or vacuum voids within the product. Those tiny air pockets or depressions that aren’t filled with solid product all compromise the integral strength. Voids in particular are a warning signs that the product’s integrity could be compromised due to insufficient material or inconsistent cooling.

So, although R.I.M. produces esthetically pleasing products suitable for a myriad of applications and industries, their durability and resistance to wear and tear is well behind solid-cast products.

Solid-Cast Polyurethane

One of our cable guards being de-molded
One of our cable guards being de-molded
One of our cable guards being de-molded

All Elasco cable ramps are manufactured using solid-cast polyurethane (PU) because it produces a superior product. During this process, liquid polyurethane is poured into our open-top molds and slowly cured over time to allow for molecules to properly interlock.

Solid-cast polyurethane is widely preferred as the material of choice in applications where a high degree of load bearing, abrasion resistance and tear strength is important – which is exactly the type of situation our cable ramps are used in every day.

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