How To Control The Color Difference Of Plastic Injection Mould Products

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How To Control The Color Difference Of Plastic Injection Mould Products

1. Eliminate the influence of plastic Injection mould injection molding machine and mold factors:

It is necessary to choose an injection molding machine with the same capacity as the injection molding product. If the injection molding machine has problems such as material dead ends, it is recommended to replace the equipment. The chromatic aberration caused by the mold gating system, exhaust groove, etc., can be solved by the maintenance mold of the corresponding part of the mold. The problem of injection molding machines and mold must be solved first before production can be organized to reduce the complexity of the problem.

2. Eliminate the influence of raw resin and color masterbatch:

(1) Controlling raw materials is the key to completely solving chromatic aberration. Therefore, especially in the production of light-colored products, the obvious influence of the thermal stability of the raw resin on the color fluctuation of the products cannot be ignored;

(2) For the color masterbatch, a random color test should be carried out before mass production. It should not only be proofread with the last time but also compared this time. If the color difference is not large, it can be considered qualified, just like the batch color masterbatch has a slight color difference, The color masterbatch can be re-mixed before use to reduce the color difference caused by uneven mixing of the color masterbatch itself.

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

Poor mixing of plastic masterbatch with color masterbatch will also make the color of the product changeable. After the masterbatch and the color masterbatch are mechanically mixed uniformly, when the material is fed into the hopper through the lower suction, the color masterbatch is separated from the masterbatch due to electrostatic action and is easily adsorbed on the hopper wall, which will inevitably lead to the change of the color masterbatch in the injection cycle. chromatic aberration.

In this case, the raw material can be sucked into the hopper and then manually stirred to solve it. For the production of colored products by adding toner, the effective method is not to use a suction machine, but to use a hot air dryer, and use the method of manual feeding to prevent the color difference caused by the separation of the toner and the masterbatch.

4. Reduce the influence of barrel temperature on color difference:

In production, it is often encountered that the temperature of the barrel changes drastically due to the failure of a heating ring or the uncontrolled long-burning of the heating control part, resulting in chromatic aberration. The color difference caused by such reasons is easy to determine. Generally, the color difference caused by the damage and failure of the heating ring will be accompanied by uneven plasticization, and the uncontrolled long burning of the heating control part is often accompanied by-product gas spots, severe discoloration, and even coking. Therefore, it is necessary to check the heating part frequently in production and replace and repair it in time when it is found that the heating part is damaged or out of control, to reduce the probability of such chromatic aberration.

5. Reduce the influence of injection molding process adjustment:

When the injection process parameters need to be adjusted for reasons other than a chromatic aberration, the injection temperature, back pressure, injection cycle and the amount of color masterbatch added should not be changed as much as possible. At the same time, the influence of the process parameter change on the color should be observed.

Avoid using high injection speed, high back pressure, and other injection molding processes that cause strong shearing effects as much as possible to prevent chromatic aberration 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.

6. Master the influence of barrel temperature and color masterbatch on the color change of the product:

Before adjusting the color difference, it is also necessary to know the trend of the product color changing with temperature and color masterbatch. Different color masterbatches vary with the temperature of production or the amount of color masterbatch, and the color change rules of their products are different. The change rule can be determined through the color test process.