Solution:
(1) A. Check if the spindle is skewed;
B. Reduce the number of layers. Usually, the number of layers for double-sided boards should be 6 times the diameter of the drill bit, and for PCB multi-layer boards, the number of layers should be 2 to 3 times the diameter of the drill bit;
C. Increase drilling speed or decrease feed rate;
D. Check if the drill bit meets the process requirements, and if necessary, grind it again;
E. Check the concentricity between the drill tip and the drill rod;
F. Check if the fixing state between the drill bit and the spring clamp is tight。
G. Check and correct the stability of the PCB drill table.
(2) Choose a high-density 0.50mm laminate cover or replace with a composite cover material (the upper and lower layers are aluminum alloy foil, 0.06mm thick each, with a fiber core in between, resulting in a total thickness of 0.35mm).
(3) Depending on the board’s characteristics, perform baking treatment before or after drilling (typically 145°C ± 5°C for 4 hours).
(4) Verify the dimensional accuracy of the tool hole and check for any offset in the positioning pin.
(5) Adjust and reset the presser foot height to 0.80mm from the board surface for optimal drilling.
(6) Select the appropriate drill speed.
(7) Clean or replace the collet chuck.
(8) Ensure no pins are installed in the panel; reposition or replace any loose or low pins on the control board.
(9) Choose a suitable feed rate or a drill with better flexural strength.
(10) Replace the aluminum cover plate with one that has a flat surface without creases.
(11) Perform board nailing as required.
(12) Record and verify the origin.
(13) Attach adhesive tape to the edge of the board at a 90° angle.
(14) Provide feedback and notify the machine repair technician for debugging and repair.
(15) Verify and notify the project team for necessary changes.
Common problems and solutions for PCB drilling: large holes, small holes, and hole distortion
Causes include: incorrect drill tip specifications; inappropriate feed speed or rotation speed; excessive drill tip wear; excessive regrinding of the drill tip or non-standard specifications; excessive spindle deflection; drill tip collapse. Issues such as larger hole diameter, incorrect hole diameter, failure to measure hole diameter after changing drill nozzles, incorrect drill nozzle arrangement, or incorrect positioning of drill nozzles.
Solutions:
(1) Check the PCB drill bit size and control system for command errors before operation.
(2) Adjust the feed rate and rotation speed to optimal settings.
(3) Replace the drill bit and limit the number of holes per bit: typically 3000 to 3500 holes for double-sided boards (four pieces per stack); 500 holes for high-density multilayer boards; 3000 holes for FR-4 (three pieces per stack); and reduce by 30% for harder FR-5 boards.
(4) Limit the number of drill bit regrinds and size changes from regrinding. For multilayer boards, sharpen after every 500 holes, allowing 2-3 sharpenings; for double panels, sharpen after every 1000 holes, and after every 2500 holes, sharpen again, drilling 2000 holes at a time. Use a tool microscope to ensure wear depth is less than 0.2mm and regrind by 0.25mm. Fixed shank drills can be reground 3 times; spade drills can be reground 2 times.
(5) Provide feedback to maintenance for dynamic deflection testing of the spindle during operation. If deflection is serious, have a professional PCB supplier repair it.
(6) Inspect the drill tip surface with a 20x magnifier before drilling, sharpening or scrapping any defective bits.
(7) Perform multiple checks and measurements.
(8) Measure the replaced drill nozzle and the first hole drilled by it.
(9) Count the tool magazine location when arranging drills.
(10) Clearly read the serial number when replacing the PCB drill bit.
(11) Check the actual hole diameter against the hole diagram when preparing the drill.
(12) Clean the chuck and carefully measure the knife surface condition after pressing.
(13) Double-check the tool number input.
