PCB Tech - Curly debris, hole plugging, rough hole wall in PCB drilling

The reasons for are: not using a cover plate or improper selection of drilling process parameters.

Solution:

(1) A suitable cover should be used.

(2) Generally, you should choose to reduce the feed rate or increase the drill speed

Common problems and treatment of PCB drilling-plugging (plugging)

The reasons are as follows: the effective length of the drill bit is not enough; the depth of the drill bit into the backing plate is too deep; the substrate material problem (with moisture and dirt); the backing plate is reused; improper processing conditions such as insufficient dust suction; drilling The structure of the nozzle is not good; the feed rate of the drill nozzle is too fast and the rise is not properly matched.

Solution:

(1) Choose the appropriate length of the drill bit according to the thickness of the PCB stack, and you can compare it with the thickness of the production board stack.

(2) The drilling depth should be set reasonably (control the tip of the drill tip to drill 0.5mm into the backing plate).

(3) A good quality PCB substrate material should be selected or bake before drilling (normally 145 degree Celsius±5 bake for 4 hours).

(4) The backing plate should be replaced.

(5) The best processing conditions should be selected, and the suction force of the drill hole should be adjusted appropriately to reach 7.5 kg per second.

(6) Change the supplier of drill bits.

(7) Set the parameters strictly according to the parameter table.

PCB drilling common problems and treatment-rough hole wall

The reasons are: excessive changes in the feed rate; too fast feed rate; improper selection of cover material; insufficient vacuum (air pressure) of the fixed bit; inappropriate retraction rate; cracks or breaks in the cutting edge of the top corner of the bit Damaged; the deflection of the spindle is too large; the chip discharge performance is poor.

Solution:

(1) Maintain the best feed rate.

(2) Adjust the feed rate and rotation speed according to experience and reference data to achieve the best match.

(3) Replace the cover material.

(4) Check the vacuum system (air pressure) of the CNC drilling machine and check whether the spindle speed changes.

(5) Adjust the retreat rate and drill speed to reach the best state.

(6) Check the status of the drill bit, or replace it.

(7) Check and clean the spindle and spring chuck.

(8) Improve chip removal performance and check the condition of chip flutes and cutting edges.

A white circle appears on the edge of the hole of the hole (the copper layer of the hole edge is separated from the base material, and the hole is blasted)

Causes: Thermal stress and mechanical force during drilling caused local breakage of the substrate; the size of the glass cloth braided yarn was relatively thick; the substrate material was of poor quality (paperboard material); the amount of cutting was too large; the drill tip was loose and not tightly fixed; PCB Too many layers of laminate.

Solution:

(1) Check the wear of the drill bit, and then replace or re-grind it.

(2) Glass cloth woven from fine glass yarn is selected.

(3) Change PCB to substrate material.

(4) Check whether the set feed amount is correct.

(5) Check whether the diameter of the shank of the drill bit and the clamping force of the spindle spring clamp are sufficient.

(6) Adjust according to the laminated data of the craft regulations

The above are the problems that often occur in PCB drilling production. In actual operation, more measurement and inspection should be performed. At the same time, strict standardization of operations is of great benefit to the control of drilling production quality failures, and it is also of great help to improve product quality and increase production efficiency.