● Stencil stripping speed
● Vacuum block
Solder paste printing refers to the process to printing solder paste on the printed circuit board for the aim of connecting electronic components, which seems like painting on walls. The quality of solder paste printing is vital for the soldering of PCB board so that PCB manufacturers will take use of specific stencil to control the solder paste printing to ensure the precision of printing.
Solder Paste Printing
Solder paste printing decides whether the soldering of printed circuit board is good or bad. With improper printing, it will cause the solder short and solder empty in soldering. In order to achieve the high quality of solder paste printing, there are a lot of elements should be considered.
Actually, PCB manufacturers should choose proper and suitable squeegee according to the difference of solder paste. But at present, the squeegee in solder paste printing is made of stainless steel.
2. Squeegee angle
The best squeegee angle in solder paste printing will be 45-60°.
3. Squeegee pressure
Squeegee pressure will affect the volume of solder paste on the surface. In principle, under other conditions remain unchanged, the higher squeegee pressure is, the lower solder paste volume will be.
4. Squeegee speed
Squeegee speed will influence the shape and volume of solder paste, which directly decides the quality of printing.
5. Stencil stripping speed
If the stencil strip speed is too fast, it is unable to keep the smooth of surface and easy to cause the problem of brush, resulting in the bad performance in surface mounting.
6. Vacuum block
Vacuum block can help PCB board lie flat on the fixed position, enhancing the compactness between stencil and PCB board. Sometimes, vacuum block can be replaced by universal pin or block for the manufacturing of low volume disposable products.
7. Warapge of PCB
The warapge of printed circuit board will result in the uneven solder paste printed surface, which is more likely to cause the short circuit.