How to control the color difference of the product during the processing of plastic molds

Product color difference in plastic mold processing plants is a common shortcoming in injection molding. ``It is not uncommon for injection molding machines to be scrapped in batches due to different colors of matching parts. Color difference affects many factors, involving the mixing of raw material resin, color masterbatch, and the same material of color masterbatch. Injection molding products, injection molding machines, molds, etc., are involved in a wide range of areas, so the color difference control skills are also one of the harder skills to master in injection molding. Next, I will introduce you in detail.

1. Eliminate the influence of injection molding machine and mold elements

It is necessary to select an injection molding machine with the appropriate capacity for the main product of plastic mold processing. Assuming that the injection molding machine has titles such as material dead ends, replace the equipment. The color difference caused by the mold casting system, exhaust groove, etc. can be dealt with by the repair mold of the corresponding part of the mold. It is necessary to first handle the injection molding machine and mold titles to be able to organize production to reduce the complexity of the titles.

Eliminating the influence of material resins and color masterbatches is the key to controlling the color difference. Therefore, especially when producing light-colored products, the significant impact of the different thermal stability of the material resin on the glory of the product cannot be ignored. In view of the majority of injection molded products The manufacturer itself does not produce plastic masterbatches or color masterbatches, so you can focus on production management and raw material inspection. That is, strengthen the inspection of raw materials into the warehouse; use the same manufacturer and the same brand masterbatch for the same product in production. The color masterbatch is produced; about the color masterbatch, we need to carry out sampling test color before mass production. It is necessary to calibrate it with the previous time and compare it in this time. The masterbatch has a slight color difference. You can mix the color masterbatch from the beginning and use it again to reduce the color difference caused by the uneven mixing of the color masterbatch. At the same time, we also need to check the thermal stability of the raw material resin and the color masterbatch. , We recommend manufacturers to exchange.

2. Eliminate the influence of uneven mixing of masterbatch and masterbatch

Poor mixing of the plastic masterbatch with the masterbatch will also make the color of the product change impermanent. After the masterbatch and the masterbatch are mechanically mixed, when they are fed into the hopper through the lower suction, the color masterbatch is separated from the masterbatch due to the electrostatic effect, and it is easy to be adsorbed in the hopper. This will inevitably result in a change in the amount of color masterbatch in the injection cycle, and then a color difference. This situation can be handled by the method of manual mixing after the material is sucked into the hopper. Nowadays, many companies choose the feeder to add the color. This saves a lot of manpower and provides a lot of assistance for color difference control, but many companies are often unsatisfactory due to improper use. The amount of color master added to the feeder at a fixed speed depends on the plasticization Time, and the plasticizing time itself is shaken, sometimes shaken or even relatively large, so to ensure a stable feeding amount, the feeding time of the feeder needs to be fixed, and the set time is less than the plasticizing time. Be careful, because the feeder outlet is small, after a period of use, the material powder accumulated in the feeder screw may form a feeding ban, and even cause the feeder to stop, so it needs to be sorted regularly.

3. Reduce the influence of barrel temperature on chromatic aberration

In the production of plastic mold processing plants, it is often encountered that a certain heating ring is damaged or failed or the heating control part is out of control and burned to form a drastic change in the barrel temperature and then a color difference. The color difference caused by this type of reason is easy to determine. Generally, the heating ring is damaged and fails. The occurrence of color difference will be accompanied by uneven plasticization, and the out-of-control and long-burning of the heating control part is often accompanied by product air spots, severe discoloration and even coking. Therefore, it is necessary to check the heating part frequently during production and find that the heating part is damaged or out of control. Replacement and repair to reduce the chance of this kind of color difference.

4. Reduce the impact of injection molding process adjustment

When the injection molding process parameters need to be adjusted for non-chromatic aberration reasons, do not change the injection temperature, back pressure, injection cycle and the amount of masterbatch added as much as possible.The adjustment also needs to investigate the impact of the process parameter changes on the glory.If the color difference is found, it should be adjusted in time. Try to avoid the use of high injection speed, high back pressure and other injection molding processes that cause strong shear effects, and avoid color differences caused by some elements such as overheating or thermal differentiation. Strictly control the temperature of each heating section of the barrel, especially the nozzle and the nozzle close to it. The heating part.

5. Grasp the influence of the barrel temperature and the amount of 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 with the temperature and the amount of color masterbatch. Different color masterbatch changes with the production temperature or the amount of color masterbatch, the product color change rules are different. It can be through the color test process. Confirm the change rules. Unless you know the change rules of this color masterbatch, it is impossible to adjust the color difference quickly, especially when you choose the color palette produced by the new masterbatch.

In summary, if you still have any questions about the above problems, you are welcome to contact us online, and we will have professional staff here to answer you.