Analysis of two kinds of PCB process faults: debris on hole wall and enlarged hole diameter

PCB process failure: debris appears on the hole wall.
Reason:
(1) the material of cover plate or base plate is inappropriate.
(2) The cover plate causes the bit damage.
(3) The vacuum pressure of the spring central head of the fixed drill bit is insufficient.
(4) The pressure foot gas supply pipeline is blocked.
(5) The helix angle of the drill bit is too small.
(6) Too many layers of laminated plates.
(7) The drilling process parameters are incorrect.
(8) The environment is too dry to produce electrostatic adsorption.
(9) The tool withdrawal rate is too fast.
Workaround:
(1) Select or replace suitable cover plate and substrate materials.
(2) Choose the cover material with suitable hardness. Such as No.2 antirust aluminum or composite cover plate.
(3) Check the vacuum system (vacuum degree, pipeline, etc.) of the machine.
(4) Replace or clean the pressure foot.
(5) Check whether the drill bit meets the standard technical requirements.
(6) The number of laminated plates should be reduced according to the technological requirements.
(7) Select the best feed speed and bit speed.
(8) The specified humidity requirements shall be met according to the technological requirements, and the humidity shall be above 45%RH.
(9) Select the appropriate tool withdrawal rate.
PCB process failure: aperture enlargement
Reason:
(1) There is something wrong with the drill bit diameter.
(2) When the drill bit is broken in the hole and dug up, the hole diameter becomes larger.
(3) caused by leaking holes.
(4) Error caused by repeated drilling of positioning holes.
(5) Repeated drilling
Workaround:
(1) The drill bit diameter must be carefully tested before drilling.
(2) The part of the drill bit broken in the hole is ejected.
(3) Pay attention to the diameter of the drill bit when repairing the hole.
(4) The position and dimensional accuracy of the positioning hole should be re-selected.
(5) Pay special attention to the diameter of the drilled hole.