The main factors that affect the filling rate of solder paste are printing speed, squeegee angle, squeegee pressure and even the amount of solder paste supplied. In simple terms, the faster the speed and the smaller the angle, the greater the force downward of the solder paste and the easier it is to fill, but the more likely it is that the paste will be squeezed onto the whetstone surface of the stencil or the risk of incomplete filling.
The main factors affecting solder paste printing are the area ratio of the stencil, the roughness of the stencil hole wall and the hole shape.
1. Area ratio
The area ratio is the ratio of the stencil window area to the area of the window hole wall.
2. Transfer rate
Transfer rate refers to the ratio of solder paste deposited on the pad in the stencil window during printing, expressed as the ratio of the actual amount of transferred paste to the volume of the stencil window.
3. The impact of the area ratio on the transfer rate
Area ratio is an important factor affecting the transfer of solder paste engineering generally requires an area ratio greater than 0.66, in this condition can obtain more than 70% of the transfer rate.
4. The area ratio on the design requirements
Area ratio of the stencil design requirements, mainly affecting the fine pitch components. In order to ensure the area ratio requirements of the micro fine pitch stencil window, the thickness of the stencil must meet the requirements of the area ratio. This requires more components of the amount of solder paste, it is necessary to increase the amount of solder paste by increasing the area of the stencil window This requires the deformation of the space around the pad, which is a major consideration in the design of the component pitch.
NeoDen ND2 automatic stencil printer
1. Four way light source is adjustable, light intensity is adjustable, light is uniform, and image acquisition is more perfect;Good identification (including uneven mark points), suitable for tinning, copper plating,Gold plating, tin spraying, FPC and other types of PCB with different colors.
2. Intelligent programmable setting, two independent direct motors driven squeegee, built-in precise pressure control system.
3. The new wiping system ensures full contact with the stencil ; three cleaning methods of dry, wet and vacuum, and free combination can be selected; soft wear-resistant rubber wiping plate, thorough cleaning, convenient disassembly, and universal length of wiping paper.
4. The scraper Y axis adopts servo motor drive through screw drive,to improve accuracy grade,operational stability and extend the service life,to provide customers with a good printing control platform.
Post time: Aug-04-2022