One, foreword
With the development of science and technology, PCB board precision (aspect ratio) requirements are increasingly high, it not only brings trouble to PCB manufacturers (cost and quality conflict), but also to the downstream customers buried serious quality hidden trouble! In the following section of the circuit board manufacturers xiaobian and everyone together to understand, hope to the relevant colleagues have inspiration and help!
Ii. Classification and characteristics of holes without copper
1. The burr inside the hole of PCB leads to the imperfection of the hole, and the burr on the hole wall is not smooth when drilling, which leads to the unsymmetry of the copper in the hole and electroplating. Once the customer debugs the copper thin part of the power hole, it may burn off and lead to open circuit of the PCB.
2. Thin copper holes without copper in PCB:
(1) thin holes and no copper in the whole board of the circuit board: the surface copper and hole copper are very thin, and most of the plate copper in the middle of the hole is eroded after micro-etching before electrographic treatment, and is covered by the electrographic layer after electrographic treatment;
(2) copper thin hole without copper in the hole: the copper plate electrical layer is uniform and normal, and the electrical layer in the hole from the orifice to the fracture shows a decreasing sharp trend, and the fracture is generally in the middle of the hole, and the fracture is to the left of the copper layer
The right uniformity and symmetry are good, and the break after the graph is covered by the graph layer.
