Molding zero-defect

Microprocessor control systems (MCS) make it possible to completely automate an IM plant. They control machines, automatically, enabling them to achieve high quality and zero defects. These systems readily adapt to enhancing the ability of processing machines. There are many moldings that would be difficult, if not impossible, to produce at the desired quality level without this feature. 

A zero-defect production of injection-molded parts is guaranteed when internal and external quality controls work properly together. In this case a QA protocol can be sent to the customer. All ranges of protection are specially significant. The automated quality control for injection molding is illustrated in the following example. 

Neither statistical methods, which are able to determine dimensions and weight of a molded part in advance with the help of a design of experiment (DOE), nor control methods, which fully automatically readjust and optimize the process, are able to prevent rejects. This means that a so-called zero-defect production (0 ppm) is desirable but impossible to achieve in practice. The goal is not to produce zero defects but to deliver. For this reason, there is no way around monitoring the process. 

The specifications on molded components are becoming tighter as molders strive to reach zero defects. This is especially true in the medical, electronic, and micro-molding areas. Inspection is not an adequate way to insure the quality of plastic components due to the large quantity produced and manpower issues. Process monitoring is currently used to try to insme quality in molded components, but if the process and the mold are not robust, the process window will be too narrow to allow for variations in the material and the environment. By placing overflow tabs at the end of fill, some of the part variation can be reduced by manipulating the flow in that area to make it more consistent with the rest of the... 

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