Weight of injection molded parts and their differences from molded parts

They are also plastic parts, but they may be injection molded parts or molded parts, which can only be judged from their molding process and details. The processing of injection molded parts is to transfer the molded workpieces through thermosetting plastics, while the molded parts are molded workpieces. Obviously, these are two different processes, so the injection molded parts and the molded parts cannot be the same.

First, let's understand the characteristics of this molding process. The thermosetting plastic transfer molding process is to close the mold before feeding, so that the plastic raw materials are heated in a separate feeding chamber and in a molten state; Then, under the pressure, it is pressed into the mold cavity at high speed through the pouring system of the mold, and continues to be heated and pressed in the mold to solidify and form.

It can be seen from this that the thermosetting plastic transfer molding used for injection molded parts is first mold closing and then pouring molding, while the molding of molded parts is first feeding and then mold closing, heating and pressure molding in the cavity. And the former has a gating system, while the latter has no gating system; In addition, the gas in the transfer mold during the molding process is not easy to be discharged in the mold cavity, so it is necessary to open an exhaust slot, while molding is not optional.

It seems that the weight of injection molded parts has a lot to do with the injection molding process, mold and a number of technical parameters; In the case of continuous production without changing the parameters, the temperature should have a greater impact on the stability of product weight, including the temperature of the mold, the temperature of the hydraulic oil, the temperature of the barrel, and so on.

During the injection molding process, the mold temperature, especially the temperature of the cavity surface, mainly depends on the stability of the molding cycle and the stability of the cooling water; The main factor affecting the hydraulic oil temperature is the efficiency of the oil temperature cooler; The temperature stability of the barrel is related to the back pressure. If the above requirements are met, it depends on the precision of the injection molding machine. If the precision of the machine can also be guaranteed, the weight of the injection molding parts will not have too much deviation, and the precision of all aspects can also be guaranteed.