In the original laser combined with electro polishing basis, using a special way at the bottom and the hole wall is coated with a layer of super smooth material, this material is the material surface friction coefficient of the lowest known in nature, so that the steel mesh wall surface is very smooth, so that the steel net 'change in the hitherto unknown printing solder paste release properties.
In the SMT process, with steel mesh printing steel mesh opening design must follow the IPC-7525 on the pad area / hole wall area of more than 0.55, while the standard is based on the friction coefficient of steel mesh wall is based on 0.3, and in the steel mesh wall surface plating super smooth coating, friction the surface coefficient is 0.03-0.06, better than the existing steel mesh surface friction coefficient is nearly 10 times. The paste is extremely easy to break in the steel net, so that we in the design of steel net, steel sheet thickness can be in the same moment, can open more small holes, or in the same opening steel plate is thicker, to ensure that the amount of tin and tin to prevent even, demoulding effect and better.
We adopt new technology of the invention, a coating on the back and the hole wall of the steel net, prepared by the special way of coating, strong adhesion, abrasion resistance, acid resistance and alkali resistance can, using food grade material, no environmental test asked, coating thickness deposited into a nano level, without any influence the size of the steel net opening itself.
Solder paste printing steel mesh in the ten years from the etching process for laser, basically no new technology, raw materials with the original 304HTA now has fine particles of new materials, FG (FG) to cut the hole wall smooth, but the friction coefficient does not change, we change light Sheng company to change rapidly with the development of new electronic products, steel net surface treatment technology of gas phase deposition, nano super smooth steel mesh.
From the above figure can be seen FG openings relative to the ordinary laser opening hole wall is smooth, and electroforming close, and light company is in FG laser polished steel line, using vapor deposition way a layer of nano materials in the hole wall and the bottom material as main component of fluorine, surface friction coefficient is 0.03. (stainless steel 0.3). The thickness of 20 nm was not affected by the vapor deposition thickness. The excellent wear resistance.
The above pattern is printed on the same printing machine with the same parameters. Compared with the common laser steel mesh, the nano steel mesh has better solder paste transfer rate and good stability.
Comparison of FG fine grain steel mesh and super smooth nano steel mesh
FG steel net
Super smooth steel wire mesh
See from the above chart, FG ultrafine grain steel started forming edge fortunately 1-6 map in printing, Figure 7 gradually began to blur, even tin phenomenon, and nano super smooth steel mesh from Figure 1 to figure 13 is always clear, stable average amount of tin. It can be printed 30 times before the steel mesh is needed to make it possible to obtain a super smooth steel mesh with a better printing performance relative to the FG steel mesh.
The above test is carried out under the same printing parameters of the same brand of the same printer
Above 0.4 BGA 0.24mm, 0.1mm thickness steel sheet
Nano steel mesh is first proposed by foreign manufacturers, but because of some key problems in the production of product defects, can not be used in the present stage, the concept of nano we said, our products relative to other company's advantage: the real nano coating thickness was about 20 nm, strong adhesion ability, high acid-base capacity, vacuum coating. Can be full coverage of the hole wall. Industry standard area ratio.