The moulder’s object should be to optimize the process and the mould in the proving phase to such an extent that consistent reproducibility of top-quality parts is ensured even with minor variations in the material, in the machine or in the environmental parameters, i.e. within the process window.  制模師的目的是對過程和檢驗階段的模具進行最優化，以保証優質零件的一致的再生能力，即使這些優質零件在材料、機器或是環境等參數上具有細微的偏差，如在過程窗口之內。

Frontal flow-the pattern of mould filling  前沿流----充模方式

In checking on what process window is available, it is a good plan to start by having a critical look at the most important process parameters. The first thing to be considered is the mould filling pattern. This is a crucial process and responsible for many defects in moulded parts, so an understanding of this operation is elementary in the analysis of many process phases. 在核對可用過程窗口時，從查看最重要的過程參數開始是一個好的計劃。而首先要考慮的便就是充模方式。充模是一個關鍵的過程，塑膠制品上的許多缺陷都之有關。因此，對它的理解在許多過程階段的分析中是最基本的。

Mould filling is a function of frontal flow. Starting invariably from the gate, the melt will spread three-dimensionally to and contact the nearest surface of the mould where it will solidify close to the wall. Initially, the core of the moulded part will remain plastic. Molten plastic will continue to flow through the center until the cavity is filled. This means that, as the cavity is being filled, melt continues to pour at the flow front out of its plastic core to settle on the wall of the mould.