The advantages of reaction injection molding (RIM) vs. plastic injection molding (PIM) can be subtle, but it boils down to the durability and long-lasting nature of the final product. RIM vs. PIM is an easy battle to discuss and decide which is better. Designing and producing products made with reaction injection molding vs. plastic injection molding must address several factors including how the piece will be used, what kinds of pressure and temperatures it will experience, how durable it needs to be and whether it will it interact with other parts. This comparison merely details the benefits of RIM.
RIM technology is simple enough to accomplish with a talented staff that is familiar with the process. It is a method in which two reactive liquid components are combined within a low pressure system. The two are a polyol and an isocyanate that are fed through tubing into the mixing head and then the molding area with supporting apparatus such as a metering piston and recirculation pump. Depending on the size of the item, the time to cool can be as little as three to five minutes before the mold is opened and the process can begin again. Hard tooling of the mold with aluminum or copper will experience the quickest cooling. In addition, RIM technology can be produced at a lower cost because of the molds themselves. A specialty RIM manufacturer will use aluminum molds for the best efficiency in large sizes and lower production rates.
PIM occurs much like RIM without the reactions and is ideal for making a large volume of products that are very consistent in size. This process typically has a low labor cost and has few scrap losses as the RIM production does. Typically, PIM has very little finishing once the item is out of the mold, but like RIM, can have expensive tooling to even begin molding.
The Comparison of RIM vs. PIM
PIM is not an unusable process, and for some products, it can be the better choice. RIM is superior in other areas that must be noted, however.
• RIM offers high impact resistance and excellent abrasion resistance that can tolerate heavy abuse without marring the surface of the item.
• The elastic memory of RIM makes it more durable and less breakable.
• Reaction injection molding provides a variable co-efficient of friction, a function of the normal pressure and rubbing velocity, for a broader range of applications.
• Sound waves are absorbed more with PIM, resulting in noise reduction for the environment in which the molded product is placed.
• RIM can be thick set molded much easier than the PIM process.
• The resilience of the final result of RIM technology is tougher than PIM.
• RIM has lower temperature, compression set and radiation resistance.
• And finally, the lower cost tooling of reaction injection molding makes it more attractive to purchasers. RIM can handle large part and low volume production at an affordable price.
In the battle of RIM vs. PIM, the winner is clearly RIM, for durability and resistance to outside influences.
Post time: 11-30-2016