![]() Reduce clamping force and prevent cavity deformationįront mold temperature is too high or cooling time is not enough The inner side of the cavity is too roughĬhange rough grain to fine grain or smooth step structureĮxcessive clamping force (mold cavity deformation) Increase the draft Angle of the die cavity Polishing the surface of the mold cavity and removing flashes In some cases the mold needs to have some tool work done on it and sometimes it needs to be changed completely with a better mold design. The main reason for drag marks to occur is a misaligned ejector system. When a part is being ejected from the mold, sometimes its surface can suffer from abrasion if the ejector system is not alligned or the draft angles are not sufficient enough to remove the part from the mold within allowed resistance. Increase ejector pin size or slow down ejection speed The ejector pin size is too small or the ejection speed is too fast Increase wall thickness where the marks appear. Thin walls where the ejector pin marks appear Increase ejector pin number or change ejector pin position The ejector pin is not in sufficient quantity or position The mold temperature is too low or too highĪdjust the mold temperature appropriatelyĪt least 0.5 degrees draft on all vertical anglesĪrtificially or or naturally balance the mold. Slow down injection speed towards the end. But when these marks are causing non-uniform, deep, asymmetric marks on the part surface.Įxcessive injection pressure or holding time These traces can be shallow enough and away from the product face. When the plastic part is ejected from the mold, the ejector pin will often leave deep or shallow traces on the plastic part. Remove residue material or enlarge the hole diameter The nozzle is blocked or the nozzle tip is too small The mold gate is too small, injection speed is too fastĭebris in the barrel causes the material superheated decompositionĬheck the nozzle, ring and feed tube for wear/corrosion or replace the machine ĭust falls into the air during mold openingĪdjust the wind and wind direction of the cooling fan (it is best to turn off the fan), cover the injection molding machine with film The raw material of the superheated melt attaches to the inner wall of the cylinderĢ. Good control of water outlet (best use dust free workshop) The drying bucket should be thoroughly cleanedĬolor pigment diffusion is poor, resulting in condensation pointĪdd diffuser or change the quality of the toner The raw material is mixed with foreign matter or the drying bucket is not cleanedġ. The specific reasons and improvement methods are shown in the following table: The main reason for the black impurities to appear is that the foreign material within the plastic melt will degrade at high temperatures. The problem of black specs is difficult to avoid in injection molding and needs to be controlled from the raw material, crushed material, ingredients, feeding, environment, and production processes to reduce the spec rate. ![]()
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