PCB drilling is a process of PCB plate making, but also a very important step. Mainly to the board drilling, wiring needs, to make a hole, structure needs, make a hole to do positioning; Multi-layer board drilling is not a hit, some holes buried in the circuit board, some on the board above get through, so there will be a drill two drill.

A drill is required to sink copper process, that is, to coat the hole with copper, so that the upper and lower layers can be connected, such as through the hole, the original hole, etc

Two drill holes do not need to sink copper holes, such as screw holes, positioning holes, heat sink, etc., these holes do not need to have copper pocket. The second drill must be behind the first, that is to say, the process is separate.

Common problems with PCB drilling

1. Drill break

Causes are: excessive spindle deflection; Improper operation of NC drilling machine; Drill nozzle selection is not appropriate; The speed of the bit is insufficient and the feed rate is too large. Too many stacking layers; There are sundries between the board and the board or under the cover plate; When drilling the spindle depth is too deep resulting in the drilling nozzle chip discharge bad hanging; Too many grinding times of the drill nozzle or beyond the service life; The cover plate is scratched and wrinkled, and the backing plate is bent and uneven; When fixing the substrate, the tape is too wide or the aluminum sheet and plate of the cover plate are too small; Feeding speed is too fast to cause extrusion; Improper operation when filling holes; Serious ash blocking under aluminum plate of cover plate; The center of welding drill tip deviates from the center of drill handle.

2. Hole damage

The reasons are as follows: take the drill nozzle after breaking the drill nozzle; No aluminum sheet or clamping back plate when drilling; Parameter error; The drill is elongated; The effective length of the drill nozzle cannot meet the thickness of the drill plate. Hand drilling; Special plate, batch front caused.

3. Hole deviation, shift, misalignment

The reasons are as follows: the drill bit deviates during drilling; Improper selection of cover material, soft and hard discomfort; Base material to produce shrinkage caused by hole deviation; Improper use of matching positioning tools; When drilling pressure foot set improperly, hit the pin to make the production plate move; Resonance occurs during drill operation; Spring collet is not clean or damaged; Production plate, panel offset hole or whole stack offset; The drill bit slides when running the contact cover plate. Scratches or creases on the surface of aluminum sheet of cover plate produce deviation when guiding the drill nozzle to drill down; No pins; Different origin; Adhesive paper is not firmly attached; The X and Y axes of the drilling machine have movement deviation; There is a problem with the program.

4. Big hole, small hole, aperture distortion

The reasons are: drill nozzle specification error; Improper feed speed or rotational speed; Excessive wear of drill tip; Too many times of regrinding of the drill nozzle or the bottom length of chip removing groove is lower than the standard; Excessive deflection of spindle itself; The drill tip collapses, and the hole diameter becomes larger; Misread the aperture; The hole diameter was not measured when the drill tip was changed; Drill bit alignment error; Insert the wrong position when changing the drill nozzle; The aperture chart is not checked; Spindle can not put the knife, resulting in pressure knife; Parameter entered wrong serial number.

5. Leakage drilling

The reasons are as follows: drill break (unclear mark); Pause midway; Program error; Unintentionally delete the program; The drilling rig missed reading data.

6. Front

The causes are as follows: Parameter error; Drill nozzle wear serious, blade is not sharp; Floor density is not enough; There are sundries between substrate and substrate, substrate and bottom plate; The base plate is bent to form a void; No cover plate; The plate material is special.

7. The hole is not drilled through (not through the substrate)

The reasons are: improper depth; The length of the drill is not enough; Uneven platform; Uneven thickness of the backing plate; Broken knife or drill nozzle broken half, the hole is not through; Batch front into the hole after copper precipitation formed opaque; Spindle clamp loose, in the process of drilling drill nozzle is short pressure; No clamping bottom plate; When making the first plate or filling holes, two pads were added, which were not changed during production.

There is a lotus-tied curling chip on the face plate

The reasons are: no cover plate or improper selection of drilling process parameters.

9. Plug hole (plug hole)

The reasons are as follows: the effective length of drill bit is not enough; The depth of the drill into the backing plate is too deep; Substrate material problems (water and dirt); Plate reuse; Due to improper processing conditions, such as insufficient vacuum power; The structure of the drill nozzle is not good; The feed speed of the drill tip is too fast and the rise is improper.

10. Rough hole wall

The reasons are as follows: the feed quantity changes too much; Feed rate is too fast; Improper selection of cover material; Fixed bit vacuum degree insufficient (air pressure); The cutting back rate is not suitable; The cutting edge of the tip Angle of the bit is broken or damaged; Spindle deflection is too large; Poor chip discharge performance.

11. White circle appears at the edge of the hole (the copper layer at the edge of the hole is separated from the base material and explodes the hole)

Causes: drilling produces thermal stress and mechanical force caused by local fracture of the substrate; Glass fabric woven yarn size is coarse; Poor quality of substrate material (sheet material); Feed quantity is too large; The drill nozzle is loose and slippery and fixed; Too many stacking layers.

The above is often the problem in drilling production, in the actual operation should be more measurement and more inspection. At the same time, strict standard operation is of great benefit to control the production quality failure of drilling hole, to improve product quality, improve production efficiency, also have great help.