Clamps, injection molds

ABS- Acrylonitrile Butadiene Styrene Closure-piercing devices, roller clamps Injection Molding Gocxl To l(X)OkGy Rigid, most often trans- lucent/opaque... 

ANSI/SPI B 151.29 Vertical Clamp Injection Molding Machines (VCIiMM) D Safety Requirements for the Manufacture, Care, and Use. 

Fig. 3. Basic hydraulic (toggle clamp) injection-molding machine components. Illustration by John W. Bozzelli Rick J. Bujanowski.

Semibatch Reactors. Semibatch reactors are the most versatile of reactor types. Thermoplastic injection molds are semibatch reactors in which shaped plastic articles are produced from melts. In mol ding thermoplastics, large clamping forces of up to 5000 metric tons are needed to keep molds together, while highly viscous polymers are forced into their cavities. Heat transfer is critical. If the molds are too cold, polymers soHdify before filling is completed if they are too hot, the time required for cooling delays production. 

Injection molding involves two distinct processes. The first is melt generation, mixing, and pressurization and flow, which is carried out in the injection unit of the molding machine. The second is product shaping, which takes place in the mold cavity. Injection molders, therefore, have two distinct parts the injection unit and the mold/clamping unit. The function of the injection unit is to melt the polymer and inject it into the mold the function of the clamping unit is to hold the mold, open and close the mold, and eject the finished product. 

The molds in a RIM-process plant are located in a separate assembly, which has devices for opening and clamping a mold and, in some cases, for changing it. The pressure in the RIM-process is considerably lower than in traditional injection molding of thermoplastics thus, the requirements for the mold material are less rigid. Molds may be made from aluminum or reinforced plastics, since high-strength steel is not necessary. 

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