Drill a hole in the centre of the blank PCB so that the copper pipe is a tight fit in the hole.
在空白电路板的中间 钻一个 小孔，使得铜管正好紧紧地固定在中间。
The commonly used hydraulic seal test and air-tight test for the closed plastic container need to drill a hole on the container body. After test, the container is wasted.
闭口塑料容器一直采用桶身钻孔进行液压和气密试验，浪费较大。
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