some talks on PCB brushing roller

Some opinion of PCB brushing roller

The brush rollers used in the PCB manufacturing process can be divided into two categories according to their functions, grinding brush rollers and cleaning brush rollers, while grinding brush rollers was applied mostly. Cleaning brush rollers are only used to clean after finished products or after grinding, its quality is very less ,  so called both of them  as grinding brush rolls.

Grinding brush rollers are divided into three categories according to the materials used: nylon needle brush rollers, non-woven brush rollers and ceramic brush rollers, which have their own characteristics in use. Nylon needle brush roller is an early brush roller used in PCB manufacturing industry.

According to different manufacturing processes, it is divided into five types: steel belt winding type, braided type, slotted embedded type, round hole embedded type and rubber plate value embedded type. Nylon needle brush rollers are divided into silicon carbide (SIC) abrasives, alumina (AO) abrasives and pure nylon according to the different abrasives contained in the nylon needle brush filaments.

Whether it is silicon carbide or alumina abrasives, the particle size distribution ranges are: 60#, 80#, 100#, 120#, 150#, 180#, 240#, 320#, 400#, 500#, 600#, 800#, 1000#, 1200#, 1500#.

Nylon needle brush roller is characterized by long service life and moderate grinding effect, especially for the surface of PCB manufacturing process under the condition of line width/line spacing (L/S) ≥200um (=8mil) and copper foil thickness ≥35 um deal with. Played an important role in early PCB manufacturing.

However, with the increasing requirements for line width/line spacing of PCB recently, the scratches unique to the nylon needle brush roller are more serious, and the impact force on the lines is large, which is very easy to cause defects such as microfilament bridging and wire breakage.. Pure nylon needle brush rollers without abrasives materials, such as volcanic ash brush rollers or pumice stone brush rollers, can be used for the grinding of thinner lines such as PCBs with line widths of 75um-150um due to the selection of nylon needle brushes and the improvement of equipment.

Non-woven brush rollers are a type of brush rollers that were selected later in the PCB manufacturing industry. According to different manufacturing processes, they are divided into three types: Flap Type, Disk Type and Sponge Type.

Non-woven brush rollers are divided into silicon carbide abrasives, alumina abrasives and pure non-woven fabrics according to the different abrasives contained in non-woven fabrics. The particle size distribution range of both silicon carbide and alumina abrasives is consistent with that of nylon needle brush rollers. The non-woven brush roller is characterized by grinding, and the surface roughness is uniform and uniform, which can significantly improve the adhesion of the photosensitive film and solder resist grinding, especially suitable for line width / line spacing ≤ 100um, copper foil thickness ≤ 35 um Manufacturing of PCBs. It has its own performance in the fields of burr removal after drilling, photosensitive film pretreatment and solder mask (anti-oxidation) pretreatment. In particular, the introduction of the solder mask pretreatment process has been proven to improve the yield or reduce the short circuit, open circuit and electrical test NG by more than 10%-15%, which is further verified by industry friends who are concerned about this issue.

   The disadvantage of non-woven brush rollers is that they have a short life and high grinding costs, but if it is calculated to improve the yield of products, there is no doubt about it! The introduction of ceramic brush rollers into PCB manufacturing industry is a matter of recent years. It is especially used for plug hole oil mill removal and PTH post-treatment. However, because of its high cost, and near non-woven brush rollers, brush rollers with similar functions have been developed. : Such as the removal of plugged ink brush rollers and PTH post-treatment brush rollers, so there is no large-scale popularization at present.