1.eliminate the influence of injection moldingmachine and mold factors.
To select an injection molding machine withthe same capacity as the main product of injection molding, if the injectionmolding machine has material angle problems, it is best to replace equipment.For the color difference caused by the mold pouring system, exhaust groove,etc., can be solved by the maintenance of the corresponding part of the mold.We must first solve the problem of injection molding machine and mold beforeorganizing production so as to reduce the complexity of the problem.
2.eliminate the influence of resin andcolor masterbatch.
Controlling the raw materials is the key tosolve the chromatic aberration completely. Therefore, especially in theproduction of light-colored products, we can not ignore the different thermalstability of raw resin on the product color fluctuation caused by the obviousimpact. Since most injection molding manufacturers do not produce plasticmasterbatches or color masterbatches themselves, attention can be focused onproduction management and raw material inspection. That is, to strengthen theinspection of raw materials in warehouse; to produce the same product aspossible using the same manufacturer, the same brand master batch, master batchproduction; for masterbatch production, we have to carry out spot check andcolor test, both with the previous proofreading, but also in this comparison,if the color difference is not big, can be considered qualified, as batchcolor. The master has a slight chromatic aberration, which can be re-mixed andreused to reduce the chromatic aberration caused by the uneven mixing of themaster itself. At the same time, we also need to focus on testing the thermalstability of raw resins, masterbatches, for poor thermal stability, we suggestmanufacturers to change.
3.eliminate the influence of unevenblending of masterbatch and masterbatch.
Mixing the plastic masterbatch with thecolor masterbatch will also make the product color changeable. When masterbatchand masterbatch are mechanically mixed evenly and fed into hopper throughdowndraft material, the masterbatch is easily adsorbed on the hopper wallbecause of static electricity. This will inevitably cause the change ofmasterbatch amount in injection molding cycle, resulting in chromaticaberration. This situation can be solved by raw material inhalation afterhopper and manual agitation. Many companies now use feeders to add colormasterbatch, which saves a lot of manpower and provides a great help for colordifference control, but many companies because of improper use, the results areoften unsatisfactory. The amount of Color Masterbatch added to the feeder at afixed speed depends on the plasticizing time, and the plasticizing time itselfis fluctuating, sometimes fluctuating or even relatively large, so to ensure aconstant amount of feeding, feeder feeding time should be fixed, and thesetting time is less than the minimum plasticizing time. When using the feeder,it should be noted that the outlet of the feeder is small. After a period ofuse, it may cause inaccurate feeding and even cause the feeder to stop running.Therefore, regular cleaning is necessary.
4.reduce the influence of barrel temperatureon chromatic aberration.
In production, it is often encountered thatthe temperature of the barrel changes dramatically due to the damage andfailure of a heating ring or the out-of-control of the heating control part. Itis easy to judge the color difference caused by this kind of reasons.Generally, the color difference caused by the failure of the heating ring willbe accompanied by the non-uniform plasticization phenomenon. The out-of-controllong-burning of the heating control part is often accompanied by the productgas spot, serious discoloration and even coking phenomenon. Therefore, it isnecessary to inspect the heating part frequently in production and replace theheating part timely when it is found that the heating part is damaged or out ofcontrol so as to reduce the probability of such color difference.
5.reduce the impact of injection moldingprocess adjustment.
The injection temperature, back pressure,injection period and the amount of chromophore should not be changed as much aspossible when the injection process parameters are adjusted for non-chromophorereasons. As far as possible to avoid the use of high injection speed, high backpressure and other strong shear effect caused by injection molding process, toprevent local overheating or thermal decomposition and other factors caused bycolor difference. Strictly control the temperature of each heating section ofthe barrel, especially the nozzle and the heating part close to the nozzle.
6.mastering the influence of barreltemperature and color masterbatch on product color change
Before changing the color difference, wemust also know the trend of product color changing with temperature and color.The color changes of different color masterpieces vary with the temperature orthe amount of color change. The change rule can be determined through theprocess of color test. It is impossible to adjust the chromatic aberrationquickly unless the variation of the Masterbatch color is known, especially whennew masterbatches are used.
