在电线和电缆制造中,过程控制和产品质量过去是在成品后取样检查,并由操作人员用接触法对成品进行测量,例如用测微计来确定产品的物理性能。这种方法是对整个产品中的很小一部分进行抽查取平均值,这不仅不具有代表性,而且对于不同操作人员或同一样品由同一操作 In the manufacture of wires and cables, process control and product quality were traditionally sampled after the finished product was measured by the operator using a contact method, such as micrometer to determine the physical properties of the product. This method averages a small sample of the entire product, not only unrepresentative but also for the same operator or the same sample by the same operator