What Is Reaction Injection Molding?

Reaction injection molding is a process where two liquid polymers are combined and then injected into a single heated mold. Also referred to as RIM, it is an option worth considering as an alternative to thermoplastic injection. When the polymers are combined and blinded, they start a chemical reaction which allows them to expand to fill the mold and set into a solid part.

The manufacturing process of RIM involves polymer liquids stored in large tanks. These are dispensed by large and high pressure pumps. If compared to vacuum cast materials, these has the upper hand because of the quick cycle times. The polymers are later re-circulated from tanks to a multi-stream mix-head on the machined aluminum mold and back to the storage tanks in a continuous loop. A piston is retracted inside the mix-head during the manufacturing process which breaks the loop.

Benefits Of Using Reaction Injection Molding:

• It uses low-viscosity liquid polymers in thermoset processes and as a result, the polymers expand. After being injected into the heated mold under high pressure using an impinging mixer, it becomes thick and hard.
• It produces strong, light weighted, durable and flexible parts which can be easily painted. It even produces large polyurethane parts, made much lighter without compromising strength, flexibility, or durability.
• The polymers eventually mix at extremely high velocity to ensure proper mixture. Therefore, if compared to injection molding, vacuum forming, pressure forming, and cast molding, RIM is superior.
• RIM is a long process to be designed and manufactured, but it is negligible to say that the result is worth the wait absolutely. It is one of the most advanced processes for manufacturing polyurethane parts.

Reaction injection molding? is useful for transportation, heavy truck manufacturing or servicing, agriculture/construction and spa industry. It offers differing wall thickness, mold-in inserts and allows parts for consolidation when compared to sheet metal. This is great for it financial value as it provides lower volume when compared to traditional injection molding. Also, it is less expensive than traditional injection molding. The labor requirements are lower, the space requirement and energy is lower too.

RIM and injection molding are similar with their name but the difference between the two is vast. RIM techniques utilize low-viscosity liquid polymers in thermoset and not thermoplastic unlike traditional injection molding. In Reaction injection molding?, raw materials and molding techniques can be selected and even customized to precisely deliver desired weight, strength, density and hardness characteristics.

RIM is significant over injection molding as it also deals with vacuum-forming, pressure-forming and cast molding. The excellent flowability of the process allows molding complex geometry including louvers, ribs, bosses and openings. It is used in different industries for various applications.

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.