充填不足Short shot.doc

充填不足Short shot 何谓充填不足？（外观） What is short shot ? (appearance) 充填不足是指无法完全填充成型品。hort shot is incomplete resin filling. 正常品会得到与模具一致的产品，而充填不足品则无法 得到所希望的形状。充填不足是在树脂流动性不足或树脂计量值偏少时产生的S Flow end of short shot mold piece is shown in Figure.1. Short shot occurs when the flowability of resin is not sufficient or when the metering value of resin is too small.。 图1. 充填不足时的状况 （图片为本公司的手柄模具，大小约为10cm）Figure.1 Appearance of short shot ( Test type handle : size about 10cm) 2）充填不足的生成原因Cause of short shot generationInsufficient flowability 如果只是因为流动性不足而导致充填不足的话，则估计有以下几种条件：When short shot occurs simply for insufficient flowability, various conditions can be supposed:（1）树脂温度偏低(1) Low resin temperature（2）模具温度偏低Low mold temperature,（3）材料流动性不足) (3) Low flowability of material,（4）注射速度偏低4) Slow injection speed,（5）注射压力偏低, 5) Low injection pressure(2-2) 计量值偏少Too small metering value 如果计量值少于产品所需的量，则必然导致充填不足。有时不仅是因计量值偏少，而且还会因计量不良所产生的差错而导致充填不足If the metering value is less than necessary for the product, short shot naturally occurs. Short shot may be generated not only by a small metering value but also by metering variation due to metering failure 2-3) 产品形状或模具问题Product shape and mold problem 产品形状和模具构造也是产生充填不足的原因。浇口尺寸偏小、分流道偏细时流动性会降低，因此也很容易导致充填不足。此外，如果产品的壁厚偏 薄，当然也很容易发生充填不足Product shape and mold structure can be causes of short shot. Small gate size and narrow runner reduce flowability to lead to short shot. When product thickness is too thin, short shot is liable to occur. 2-4) 排气口不合适Improper vent 流动末端排气不畅时有时也会出现充填不足。排气口应尺寸充足，位置适当In a flow end, an inefficient gas vent may cause short shot. A vent should be of a sufficient size at a proper position.。 2-5) 预干燥不足Shortage of predrying 如果因与上述相同的原因而产生大量气体，则在流动末端有时也会出现充填不足。必须预先进行适度干燥以去除水分等By the same reason as above too much gas generation may cause short shot at a flow end. Proper drying is necessary for water removal 2-6) V－P切换V-P switching 是指注射→保压的切换位置。如果这一切换位置过早（也就是过早地转移到保压阶段），流动性就会整体下降，从而导致充填不足This means the switching position from injection to