A type of screw and nut with coarse pitch was applied to realize thread core demoulding automatically.

采用螺距粗的螺丝和螺母实现螺纹型芯自动脱模。

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Production costs born by Party B: Party B shall bear the extrusion nozzle mould cost 3000 Yuan，and the cost of plastics screw thread of 4000 Yuan.

乙方负担的制作费用：乙方承担挤出嘴模具费3000元，塑料丝扣磨具费4000元。

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Top view of roundhead slotted screw. Selection box represents thread diameter.

圆头一字槽螺钉的俯视图。选择框代表螺纹直径。

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Manipulating the shape of the threads using this method, called thread-rolling, was thought to be impossible because it would be too hard to control the structure of the screw if metal oozed into odd shapes.

FORBES: Magazine Article