原帖由 雷凱欣 於 2005/12/13 23:47 發表
鑽臺:
- 膠 + 金屬, 唔記得邊度買
- 木墊 DIY, 免鑽爛鑽臺
- 制 : 有鋁片係 forward, 無鋁片係 reverse
Place wood under PCB during drilling have more important advantage:
It can prevent crack at bottom side of PCB.
When drill head is about to reach other side of PCB, the PCB material in front of drill head is very very thin. This thin structure will can't support the the presure act on it and so crack.
Another point need take care to preven crack is:
When you feel it is about to reach other side of PCB (the resist fore to drill is decrease). Decrease the fore act on the drill.
Above is common knowledge for all drilling job. |