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Control of temperature, pressure and speed parameters in injection molding process

Melt temperature is very important in the injection molding process. The melt temperature can be measured at the nozzle of the injection molding machine, or roughly estimated using the air injection method. The temperature setting of the barrel depends on the melting temperature of the plastic melt, screw speed, back pressure, injection volume and injection cycle. If the operator does not have experience with a particular plastic, the test should begin with the lowest allowable temperature setting. In order to facilitate precise control of the melting temperature, the barrel is usually divided into a plurality of heating zones, each of which can be set to a different temperature. If the injection time is long or the operation is at high temperature, the temperature of the first zone should be set to a lower value, which will prevent premature melting and separation of the plastic. Before starting the injection molding process, make sure that the hydraulic oil, hopper sealer, mold and injection cylinder are at the correct set temperature.

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Matching relationship between pigments, plastic raw materials and additives

The colorants used in the masterbatch must pay attention to the matching relationship between colorants, plastic raw materials and additives in the masterbatch technology. The key selection points are as follows. 1. The colorant cannot react with resins and various additives, has strong solvent resistance, low mobility and good heat resistance. In other words, the masterbatch cannot participate in various chemical reactions. Carbon black can control the curing reaction of polyester plastics, so carbon black materials cannot be added to polyester.

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