In the drilling process of PCB board, the hole size is not allowed, and how to deal with the distortion. Improper feeding speed or rotating speed; Excessive wear of the drill bit; Too many times of regrinding of drill tip or the length of chip removal groove is lower than the standard; Excessive deflection of the spindle itself; Drill tip collapse, drill hole diameter increased; Misreading aperture; Hole diameter not measured when changing drill tip; Drill bit misalignment; The position of the drill bit is wrong when changing the drill tip; Failure to check the aperture map; The spindle can not put the knife, causing pressure knife; Parameter.
Then find a solution to the problem:
(1) before operation, drill size and control system should be checked to see if there is any error in the instruction.
(2) adjust the feeding speed and speed to the optimal state.
(3) change the drill bits and limit the number of holes per drill bit. Usually according to the double panel (each pack four) can drill 3000~3500 holes; 500 holes can be drilled on the high density multilayer board; 3, 000 holes can be drilled for fr-4 (three in each stack); For the harder fr-5, the average decrease was 30%.
(4) limit the number of drill regrinding and the change of regrinding size. For the multi-layer board, drill 500 holes for cutting edge grinding once, allow cutting edge grinding 2~3 times; The cutting edge can be grinded once for every 1000 holes drilled; For the double panel, drill 3000 holes every time, and then drill 2500 holes; Drill 2000 holes with another grinding. Timely regrinding of the drill bit can increase the number of regrinding of the drill bit and increase the life of the drill bit. As measured by tool microscope, the wear depth within the whole length of the two main cutting edges should be less than 0.2mm. When regrinding, remove 0.25mm. The fixed shank drill can be reground for 3 times; Regrind the spade bit twice.
(5) give feedback to the maintenance for dynamic deflection tester to check the deflection of the spindle during operation. In case of serious deviation, professional suppliers will repair it.
(6) check the cutter surface with a 20-fold mirror before drilling, and grind or discard the defective drill tip.
(7) multiple checks and measurements.
(8) when the drill tip is changed, the drill tip can be changed to drill the first hole.
(9) when arranging the drill bits, the position of the tool holder should be clearly counted.
(10) see the serial number clearly when changing the drill tip.
(11) check the actual aperture of the aperture diagram one by one when preparing the knife.
(12) clean the nozzle, and carefully measure and check the condition of the blade surface after pressing the knife.
(13) in the input tool number to check repeatedly.