![]() ![]() For any technical questions, please contact our engineering team at. If above methods won’t help, then the last way to solve ejector pin marks is mold release agent. ⑤If the holding time is too long, it is easy to produce residual stress, and the ejectior white mark appears, so the holding time should be shortened. Thus hold pressure should be properly reduced. ④ If the pressure holding pressure is too high, the stress in the plastic parts is heavy, and it is easy to cause the white mark when subjected to ejector force. ③If the injection pressure is too high, the residual stress in the plastic parts is also high, resulting in white mark, so the injection pressure should be properly reduced. So the cooling time should be prolonged appropriately. When the local force is too strong, the white mark will occur. ②If the cooling time is too short, the stress in the plastic parts is difficult to balance fully. Therefore, the melt temperature should be lowed to reduce the difference with mold` ① If the temperature between molten plastic and mold differs greatly, the residual stress in plastic parts is increased, and it is easy to cause white mark when subjected to local force. Therefore, it is a good method to release vacuum between core and plastic parts, such as installing air valve in core to release vacuum. ⑥For plastic parts with core, demoulding is difficult and white mark is easy to occur. Increase the cross section area of the ejector rod ⑤)If the contact surface between the ejection rod and the plastic part is too small, the local stress of the plastic part is very high, causing white ejector mark. ④ In order to improve the strength of the ejection area, the local area could be strengthened from the structure and wall thickness. ③If the mold draft is too small and demoulding resistance of the plastic part will increase. Therefore ejection system should be placed at the thick wall area. ②If ejector pin is placed in the weak area of the plastic part, it will aggravate the white phenomenon. Therefore, the surface roughness in the cavity should be reduced. ①If the surface of cavity is too rough, release resistance is increased and ejector white mark is caused. The specific analysis could be traced to either plastic molds or molding process. What are the reasons for ejector mark and how to eliminate them? Well, the glossy or white imprints defect is usually due to the excessive pressure at the white area of the plastic parts where the chemical resistance and mechanical properties were greatly weakened. This mark doesn’t only affect cosmetic look of the A class part, but also easily gets cracked during actual use of the products Therefore it is very important to prevent ejector pin marks before they happen. Please Support Car-Seat.Org with your purchases of infant, convertible, combination and boosters seats from our premier sponsors above.For injection molders, it should be very common to see white ejector mark or pin push appear on the plastic parts in contact with the ejector pin during the process of ejection. Before posting or using our website you must read and agree to our TERMS. If you are unsure about information provided to you, please visit a local certified technician. Use Tamiya Extra Thin to bond the disc in place. The flash is thinner than any sheet styrene you could get. ![]() All information is provided on an as-is basis. Punched disks- If you have some old kits with really bad flash on the sprues (really thin skin of plastic usually between parts and the sprue frame) use this to punch circles from instead of sheet styrene if the ejector marks are shallower. Car-Seat.Org makes no representations as to accuracy, completeness, currentness, suitability, or validity of any information on this site and will not be liable for any errors, omissions, or delays in this information or any losses, injuries, or damages arising from its display or use. All opinions at Car-Seat.Org are those of the individual author for informational purposes only, and do not necessarily reflect any policy or position of Carseat Media LLC. These are the rules you must follow to restrain your children safely. ![]() You must read your carseat and vehicle owner’s manual and understand any relevant state laws. ![]()
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