Reaction injection molding

What is Reaction injection molding-RIM

RIM (reaction injection molding), Chinese is commonly known as reaction injection molding. It is the late 1970s, first developed in Europe and America. It is different from the traditional injection molding and another molding process is a special process.

The principle is:

The two reaction materials (polyurethane component and resin mixture ) with a stirrer were placed in a temperature-controlled feed tank. It through accurate measurement, at high pressure into the mixing head at the start of injection. The mixing head of the valve to open, the reactants into the mixing chamber under pressure, speed fierce collision. It was near the atmospheric pressure and then flows into the mold. The exothermic chemical reaction in the mold to form a polyurethane polymer. This process can be simplified to Store → Measurement → mixing → filling → curing → top out → post-processing.

The reaction injection molding process is particularly suitable for large-scale ( large ) housing members.

PU resin first by Bayer (Bayer) (PU industry founder ), Professor invented in 1937. It has been 70 years old.
Polyurethane with high strength, abrasion resistance, tear resistance, flex resistance, low-temperature resistance, and oil resistance. With excellent chemical resistance and good blood compatibility, etc. , etc. Polyurethane foam products made of resin, elastomers, coatings, adhesives, fibers, synthetic leather. And other varieties of auxiliary surface material, which is widely used in transportation, electronics, shipbuilding, civil engineering, light industry and textile and other sectors, products and varieties yearly basis. The material industry occupies an important proportion of the current usage of the PU after PP, ABS, PVC.

Since the late 1930s since the advent of its applications continue to expand, production increased year by year.It is developing very rapidly.

Reaction injection molding has the advantage ( own summary, we hope to supplement )

1, shorten product development cycles, reduce product development costs

RIM technology to make product design becomes freer, more casual. And its expression on the product to better reflect the designer’s whim. Because of the low viscosity of the reaction material, good fluidity. It can be very small in the case of pressure under molding complex parts; due process of low-pressure injection of RIM. Low requirements of the mold, the mold is usually done using epoxy or aluminum material. So the cost is only a fraction of the equivalent injection mold, the processing cycle more is the injection mold can not match. The process is particularly suitable for short production and prototype production, can greatly shorten the product development cycle and saving development costs and speed to market share opportunities ;
2, can be molded article of a large area of good quality and the appearance and structure of the

Reaction injection molding Procedure

RIM molding procedure of product size and stability, aesthetically pleasing ( up to Class A surfaces ), impact resistance, and good corrosion resistance ( up to PC / ABS performance ), for forming a larger area of housing has unparalleled advantages. RIM product thickness range is extensive, the same cross-section of molded parts, it  can vary between from 6mm to 28mm, which is the other process can not be compared, it can be integrally molded article thickness variations, in order to improve the quality of products reliability, good performance surface coating, which can meet different process requirements, formulated by adjusting the ratio of raw materials,it  can be made into a hard surface, such as density polyurethane foam structures of different products, to meet the diverse needs of customers ;

the product package inserts the simple process

A variety of inserts can be placed in the injection mold before the RIM material, so that the RIM material in the molding process to complete the package insert, steel or aluminum structural frame, electronic sensors, circuit boards, batteries, antennas, magnets, glass, metal parts so you can use RIM technology package, thereby reducing or even eliminating secondary processing sectors, so you can: Protect your important and sensitive components from dust, oil, corrosive chemicals pollution; make your product You can work in wet or even water; increased intensity of your product and protect critical components from impact damage from impact or slow; way so your products can be in more extreme environments.

Easy to mold paint spraying

In the RIM process, prior to injection can be coated with polyurethane paint and gel-coat in the mold. Gel-coat or polyurethane paint in the custom injection molding process and polyurethane materials combined into one, resulting in mold decoration finished parts, greatly reducing the cost and increasing the secondary painting after processing efficiency.

RIM technology because of its superior product performance are widely used in automotive parts and modification parts, engineering machinery covering parts, medical equipment, instrumentation, electronics, machinery and equipment covering parts, industrial parts, chemical components, sports, and other fields, as alternative materials such as metal, has incomparable advantages and prospects.

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