One, Introduction
Low pressure reaction injection molding (Reaction, also known as Injection Moulding, low-pressure perfusion, RIM) is a new technology applied in the production of rapid molding, it will be a two-component polyurethane material by mixing, under normal temperature, low pressure injection mold rapidly through the material, polymerization, crosslinking, curing and other chemical and physical the process of forming products. Because of the raw material is liquid, with less pressure to quickly fill the die cavity, thus reducing the clamping force and mould cost, particularly suitable for the production of large parts.
RIM low-pressure reaction injection is mainly used for small batch trial in the process of product development, and small batch production, simple structure and large thick wall panels and uneven wall thickness products. Mainly used in medical, industrial products, chassis, cabinet, trolley, table, auto parts, automobile market, chemical container, beauty, sports and leisure equipment, large and medium-sized plastic shell. The annual output of tens, hundreds of thousands of pieces of small batch production, particularly applicable.
Two, RIM low-pressure perfusion process
The mold is closed, due to the action of the spring ring, the resin is pushed to the front end of the nozzle, the inlet valve open the pressure tank, the liquid resin pressure by feeding tube and injection nozzle, into the mold cavity is heated to 13 degrees Celsius; when the cavity is filled, with the increase of injection pressure, cone valve lift to close the vent hole, the liquid cavity filled with resin, heating and curing; pressure reducing resin after curing, so that the material conveying pipe left unloading back to storage tanks for second cycles under the action of gravity; and then open the mold, remove products, cleaning the mold, the work period is over and turn the next molding cycle. This process can be simplified as: storing, metering, mixing, molding, curing, demoulding and postprocessing.
Three, RIM low pressure perfusion process advantages
The utility model has the advantages of high efficiency, short production period, simple process and low cost. The utility model can be made into different parts with different density, hardness and elasticity
Molding product packaging effect is good, can meet the design verification, structural testing and other purposes
Compared to the VCM vacuum injection molding process, the product size is larger, suitable for the formation of large wall thickness of the product and no shrinkage mark
Compared with the traditional mold process and process, the cost and cycle are greatly reduced
Four, the current production process of rapid tooling
(one) imported automatic RIM equipment, using METTON PENTAM material molding
METTON PENTAM is a new type of olefin crosslinked thermosetting resin, in a very short time to produce large, shaped workpiece with complex shape. The material used for RIM low-pressure perfusion molding technology, in mold colleagues polymerization and molding, especially adapted to the current market for small - in the amount of large span production "," energy saving "production demand, rapid prototyping is a new generation of.METTON PENTAM in use of new technologies, new techniques and new varieties, so that more areas can experience the extraordinary performance of materials in the production process.
(two) FRP process
Glass fiber reinforced plastics:
A molding process, the most widely used model of short period, easy molding, high strength ratio (elastic modulus of steel is 2 - 3 times), which is suitable for covering parts and other products in small batch production complex. The monthly output in 200 -- 1000.
FRP material composition:
TM - 196 unsaturated polyester resin is a common type of resin, moderate viscosity, good toughness and mechanical strength. Especially suitable for hand lay up molding glass steel shell and ship parts such as vehicle glass steel products production. This product has passed the China approval of the classification society.