How to control the color difference of injection molding machine

1.To choose an injection molding machine with a capacity equivalent to that of the injection molded product, if the injection molding machine has problems such as material dead ends, it is best to replace the equipment. For the mold casting system, exhaust grooves, etc., which can cause color difference, it can be solved by the maintenance mold of the corresponding part of the mold. The problems of injection molding machines and molds must be solved before the production can be organized to reduce the complexity of the problem.

2. Eliminate the influence of raw resin and color masterbatch

Controlling raw materials is the key to thoroughly solving color differences. Therefore, especially in the production of light-colored products, the obvious influence of the thermal stability of the raw material resin on the color fluctuation of the product cannot be ignored.

3. Eliminate the influence of uneven mixing of color masterbatch and masterbatch

Poor mixing of plastic masterbatch with color masterbatch will also make the product color volatile. After the masterbatch and the masterbatch are mixed uniformly, when they are fed into the hopper through the lower suction, the masterbatch is separated from the masterbatch due to the electrostatic effect and easily adsorbed on the hopper wall. This will inevitably cause the change of the amount of the masterbatch during the injection cycle, which will cause Chromatic aberration.

In this case, the raw materials can be sucked into the hopper and then manually stirred. For adding colored toner to produce colored products, the most effective method is not to use a suction machine, but to use a hot air dryer, using artificial feeding to prevent the color difference caused by the separation of toner from the masterbatch.

4.Reduce the impact when adjusting the injection molding process

When it is necessary to adjust the pet preform injection molding process parameters for non-color difference reasons, try not to change the injection temperature, back pressure, injection cycle and the amount of color masterbatch. At the same time, adjust the process parameters to observe the impact of color changes. If you find that the color difference should be adjusted in time.

As far as possible, avoid using high injection speed, high back pressure and other injection molding processes that cause strong shear, and prevent color differences caused by local overheating or thermal decomposition. Strictly control the temperature of each heating section of the barrel, especially the nozzle and the heating part close to the nozzle.