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注塑制品开裂的原因分析 Analysis of the cause of the cracking of the injection molding products 开裂，包括制件表面丝状裂纹、微裂、顶白、开裂及因制件粘模、流道粘模而造成或创伤危机，按开裂时间分脱模开裂和应用开裂。主要有以下几个方面的原因造成： Cracking includes cracks, cracks, cracks, whiteness and cracking on the surface of the parts, as well as damage caused by die sticking and flow path sticking. It is demoulding and cracking according to the time of cracking. The main reasons are as follows: 1.加工方面： 1. aspects of processing: (1)加工压力过大、速度过快、充料愈多、注射、保压时间过长，都会造成内应力过大而开裂。 (1) excessive processing pressure, faster speed, more charging, injection and longer holding time will cause excessive internal stress and crack. (2)调节开模速度与压力防止快速强拉制件造成脱模开裂。 (2) adjust the speed and pressure of the open die to prevent the rapid and strong pullout to cause dehiscence and cracking. (3)适当调高模具温度，使制件易于脱模，适当调低料温防止分解。 (3) properly adjust the temperature of the mold to make the parts easy to die out, and to properly adjust the temperature of the material to prevent the decomposition. (4)预防由于熔接痕，塑料降解造成机械强度变低而出现开裂。 (4) to prevent the cracks due to the weld mark and the degradation of the mechanical strength caused by the degradation of plastic. (5)适当使用脱模剂，注意经常消除模面附着的气雾等物质。 (5) properly use the demoulding agent, and pay attention to the frequent elimination of air mist and other substances attached to the surface of the mold. (6)制件残余应力，可通过在成型后立即进行退火热处理来消除内应力而减少裂纹的生成。 (6) the residual stress of the workpiece can be reduced by heat treatment immediately after the molding to reduce the internal stress and reduce the formation of the crack. 2.模具方面： 2. aspects of mold: (1)顶出要平衡，如顶杆数量、截面积要足够，脱模斜度要足够，型腔面要有足够光滑，这样才防止由于外力导致顶出残余应力集中而开裂。 (1) the ejection must be balanced, for example, the number and area of the ejector must be enough, the inclination of the ejection must be enough, the cavity surface must be smooth enough, so as to prevent the cracking due to the external force leading to the residual stress concentration. (2)制件结构不能太薄，过渡部份应尽量采用圆弧过渡，避免尖角、倒角造成应力集中。 (2) the structure of the workpiece can not be too thin, and the transition part should be used as far as possible to use the arc transition to avoid the stress concentration caused by the sharp angle and the chamfering. (3)尽量少用金属嵌件，以防止嵌件与制件收缩率不同造成内应力加大。 (3) metal inlay is used as little as possible to prevent the increase of internal stress caused by the different shrinkage rate of the embedded parts and the parts. (4)对深底制件应设置适当的脱模进气孔道，防止形成真空负压。 (4) a proper demoulding intake passage should be set up for deep bottom parts to prevent the formation of vacuum negative pressure. (5)主流道足够大使浇口料未来得及固化时脱模，这样易于脱模。 (5) the mainstream road is sufficient for the ambassador's gate not to be cured when it is cured, so that it is easy to die.