With the development of electronic information industry, terminal electronic products have higher and higher requirements for the refinement of printed circuit board industry. Drilling is an important link in PCB processing, which has developed to the level of minimum aperture of 0.08mm and minimum hole spacing of 0.1mm or even higher. In addition to through holes and parts holes, there are also slot holes, special-shaped holes and board shapes, all of which need to be inspected. In PCB drilling process, it is necessary to control the following possible quality problems: porosity, hole leakage, displacement, wrong drilling, non-penetration, hole loss, partial waste, burr and hole plugging.
1. Orifice bubble reason:
When developing, the developer is not replaced in time, and the dry film mixture in the aging developer enters the hole, which is not cleaned in the subsequent cleaning, and remains in the hole after drying, and orifice bubbles will appear. In this case, the thickness of copper plating layer will gradually become thinner into the hole, and finally it will not be plated. In addition, this kind of defect will also occur if the gloss agent is not well controlled.
Quality hidden trouble: When surface mounting is done in the later stage, air is hidden in the hole, which may burst when it encounters high temperature. Soldering can also cause virtual welding and so on.
2. Reasons for insufficient plug hole:
There are many reasons why the plug hole is not full, such as not using aluminum sheet to plug the hole, not adding boiling water, not using resin hole; The hole is greater than 0.3mm;; Operator's manipulation problems, such as strength and knife direction.
Quality hidden trouble: there may be problems such as false welding and false welding on the pad.
3. Reasons for resin and copper delamination:
There are many reasons for resin and copper delamination, most of which are caused by making the next process before the resin plug hole is filled, and problems such as uneven polishing, adjustment of equipment parameters, adjustment of pressure and temperature, and resin raw materials may also lead to resin and copper delamination.
Quality hidden trouble: because the resin plug hole is not filled, there will be depression in electroplating, resistance to chip welding in the later stage, and false welding will occur.
