What’s it Entry and backup board?
2017-11-21 08:23Writer: qyadminReading:
Entry board definition
When the PCB is drilled, the PCB placed on the CCL is called "Entry Material". It is a kind of material that is placed on the board to be processed when the PCB is drilled mechanically to meet the requirements of the processing technology
Main feature of entry board
As a secondary material for PCB drilling, the entry board has five main functions:
① protect the surface (copper foil protection copper clad surface, or substrate copper conductive surface), to prevent pressure foot crush board surface;
② fixed bit, drill bit to reduce the swing amplitude, offset, so that the drill can be accurately positioned; improve the accuracy of the hole to prevent the broken drill bit;
③ to prevent the hole on the substrate burr;
④ assist the drill to distribute the heat and reduce the bit temperature;
⑤ to help clean the drill bit groove; prevent the greasy hole; reduce the bit wear and broken drill.
The performance requirements of the entry board are: soft enough; small thickness tolerance; smooth and not easy to deformation; high temperature; low hygroscopicity; surface without impurities, foreign bodies, such as obvious defects.
Backup board definition
Drilled hole under the circuit board, the machine surface in direct contact with the plate-like litter, known as the backing plate (Back-up board). It is a printed circuit board mechanical drilling plate placed below to meet the processing requirements of the material.
The main effect of the backup board is:
① reduce the substrate burr hole);
② drilling through the PCB board processing, play a role in protecting the drilling machine table;
③ reduce bit temperature, reduce bit wear;
④ part of the drill bit on the clean sweep;
⑤ to a certain extent, to play its positioning effect, improve drilling accuracy.
main requirements of backup board
In order to ensure the quality of the hole machining of the substrate, the requirements of the backup board are as follows: the formation is better, the dimension tolerance is small, the cutting is easy, the surface is required to be hard and flat, the material does not produce viscosity or release chemical substances to pollute the wall or the needle, As well as drill cuttings require fine and powder, easy chip removal. Suitable hardness, resin content or other impurities less content, a good degree of curing, will not produce sticky or release of chemical pollution hole wall or drill bit.