Cooling clamping unit

The status of mold and clamping unit during the holding pressure phase is identical with the one of the cooling phase. 

The purpose of the injection unit is to heat and melt the polymer, inject the melt into the cavity, and apply pressure during the cooling phase. The most common type of injection molding machine is the reciprocating screw. In this type of machine, the screw rotates to plasticize the polymer, moving backward to deposit a volume of polymer melt ahead of the screw (shot). Once the correct shot size has been built, the screw then moves forward to inject the melt into the mold. Injection molding is a discontinuous process, and the clamping unit allows for the mold to open and close for part removal and to provide pressure as the cavity is filled. This is depicted in Fig. 1.19. 

The basic principle of injection moulding is to inject molten polymer into a closed, cooled mould, where it solidifies to give the product. The moulding is recovered by opening the mould to release it. An injection-moulding machine has two principal parts the injection unit the clamp unit, or press. This is illustrated in Fig. 1.1. 

Conversion into 3-ethyl-3-methylcydohexanone. Prepare a solution of ethyl-magnesium iodide in 120 ml of ether from 18.7 g (0.77 mol) of dry magnesium turnings and 120 g (0.77 mol) of ethyl iodide in a 500-ml, three-necked round-bottomed flask equipped with a sealed stirrer unit, a pressure-equalising funnel and a reflux condenser. When all the magnesium has dissolved, clamp the flask in a cooling bath of Cardice-acetone and replace the condenser with a low-temperature-reading thermometer. When the temperature has fallen to... 

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