SMT printing machine solder paste brush more also known as more tin, this is a smt common solder paste printing quality bad. In the actual production, if you find that you need to find the reason to analyze and improve, otherwise the soldering will cause quality impact on the back.
The reason for more tin is mainly stencil, scraper, paste three factors, the following combination of these elements are analyzed as follows.
1. Stencil problem
The problem of the stencil is mainly too large aperture, resulting in a large amount of solder paste seepage, resulting in more tin.
Improvement method: re-open the stencil, stencil openings to maintain the inner cut and outer expansion, openings smaller than the actual pad one-third.
2. Scraper problem
Squeegee problem mainly lies in the speed, pressure and angle of the squeegee, squeegee speed to keep at about 5S a board, the angle to keep at 45-60 degrees, the pressure according to the actual production of the product to do the corresponding attempt to adjust.
3. Solder paste problem
Solder paste problem is also caused by the main problem of more tin, solder paste fluidity will cause more tin.
Improvement methods: paste back to the temperature and stirring time is reasonable (back to the temperature of more than 30 minutes, stirring time control in 10-15 minutes), with a stick stick warping a little bit of solder paste to lift up, keep the solder paste constantly flowing is a reasonable state.
SMT SMD stencil solder paste printing more, will cause more tin, more tin will cause welding even tin and other bad, set up a SMT SPI machine behind the solder paste printing machine to detect the quality of the printing of the solder paste, you can better solve the problem of poor printing of the solder paste.
Features of NeoDen ND1 stencil printer
PCB parameters
Max. plate size (X x Y) 450mm x 350mm
Minimum plate size (Y x X) 50mm x 50mm
PCB thickness 0.6mm ~ 14mm
Warping quantity Max. PCB diagonal 1%
Max. plate weight 10KG
Plate edge clearance Configuration to 3mm
Maximum bottom clearance 20mm
Transmission speed 1500mm /second(Max)
Transfer height from the ground 900 ±40mm
Transfer track direction Left – Right, Right – Left, Left – Left, Right – Right
Transmission mode Section-type track
PCB clamp mode
Software adjustable pressure of the elastic side pressure
Post time: Nov-15-2023