PCB Drilling Process Defects And Solutions
PCB hole size is not allowed in the drilling process encountered problems, first of all, to analysis the reasons of the problems, mainly include the following: drilling tsui specification error, feed speed or speed is inappropriate, excessive deflection drill tip excessive wear, spindle itself, drill tip crack tip, wrong size, change drilling tsui not bore, the drilling tsui alignment error, in drill tip position when wrong, did not check the aperture figure, spindle will not fit dao caused by pressure, etc.
PCB drilling process defects and solutions
After determining the cause, the following is to find out the relevant solutions.
(1) before operation, check the size of the drill bit and whether the command of the control system is wrong.
(2) adjust feed rate and rotation speed to the optimal state.
(3) change the drill bit and limit the number of drilling holes per drill bit. Usually 3000~3500 holes can be drilled according to double panels (four pieces per stack); 500 holes can be drilled on high-density multilayer board. 3000 holes can be drilled for fr-4 (three blocks per stack); For harder fr-5, the decrease was 30% on average.
(4) limit the number of bit re-grinding and the change of re-grinding size. For drilling multilayer board, cutting edge grinding is allowed for 2~3 times for drilling 500 holes. Cutting edge can be sharpened once per 1000 holes drilled; For double panel drilling 3000 holes, cutting edge grinding once, and then drilling 2500 holes; Then sharpen the edge and drill 2000 holes. Bit re-grinding at the right time can increase bit re-grinding frequency and increase bit life. As measured by tool microscope, the wear depth within the full length of the two main cutting edges should be less than 0.2mm. When regrinding, 0.25mm should be removed. Fixed-handle drill bit can be reground 3 times; Shovel bit is reground 2 times.
(5) feed back to the maintenance to conduct dynamic deflection tester to check the deflection of the spindle in the operation process. In case of serious problems, the professional supplier shall fix them.
(6) check the knife surface with 20x mirror before drilling, and grind or scrap the bad drill bit edge.
(7) check and measure multiple times.
(8) the changed bit can be measured when the bit is changed, and the first hole is drilled when the bit is changed.
(9) when arranging drill bit, count the position of tool storehouse clearly.
(10) see the serial number clearly when changing the drill bit.
(11) check the actual aperture of the aperture map one by one when preparing knives.
(12) after cleaning the chuck, carefully measure and check the knife surface after pressing the knife.
(13) repeatedly check the tool number when entering it.