The process of roto molding was actually invented in the 19th century and it has been used popularly since the 1940′s but in recent decades, it has increased greatly in usage due to improvements in the rotational molding process.

Rotational molding uses a heated mold that melts the plastic and rotates so that the plastic forms to the inside of the metal mold. This process is different from other processes related to thermoplastics, such as injection molding and blow molding.


Because this process requires the mold to be heated and cooled, it takes considerably longer to produce product than other molding process like injection molding. 

Roto molding has a number of advantages including that it is much easier to produce larger cases using rotational molding. Rotational molding will naturally produce thicker plastic corners and edges with thinner flat walls making it the ideal solution for a lightweight, yet very rugged and durable hard case. 

 Roto molding also creates much less waste than other molding processes; excess material is ground down to be reused. From the manufacturer’s perspective, roto molding also offers the ability to experiment with wall thickness to achieve an optimal ratio of material used to end product quality; other molded cases do not benefit from this option.

All of this requires more care on the part of the manufacturer: roto molded cases are produced in less mass than other molded cases and tend to have superior strength and durability. This makes the hard case hardware and features much more easily customizable.

Injen Technology of Pomona, CA uses roto molding to manufacture their new line of EVOLUTION COLD AIR INTAKE KITS.  
Each cold air intake is designed for the following: 

• Dyno-tuned as a System for GUARANTEED SAFE Horsepower and Torque gains.
• Officially the largest SuperNano-Web dry filter on the market.
• The first stand alone air filter chamber for ample on-demand air supply.
• Sleek and sexy design.
• The first built-in Filter Minder for quick, easy and accurate filter inspections. 
• Designed and built in the USA from cross-linked polyethylene for outstanding durability and heat insulation. 
• Durable stainless steel hardware.
• Perfect OE fitment.

They use rotomolded products because it gives them the means to meet the demands of a hot engine compartment in terms of driving cold air into the engine.