Automatic solder paste printer is an essential piece of equipment in the SMT assembly line, the stencil clogging problem of the solder paste printer is a common phenomenon in the soldering process, which will have an impact on the printing quality and productivity.
I. What are the reasons for solder paste blocking stencil?
1. Solder paste quality
Automatic solder paste printing machine in the printing process due to the composition of the paste will continue to change, which is more obvious is the viscosity change. When the temperature is higher, the flux volatilization faster, when the humidity is higher, the water absorption of the paste will be more prominent, these are the reasons that lead to changes in the viscosity of the paste, thus affecting its surface tension, and tension changes will directly affect the changes in the situation of the mesh, which occurs in the stencil clogging.
2. Stencil quality
Automatic solder paste printing machine paste stencil opening is reasonable, the viscosity of the selected paste, the size of the tin beads, scraper material, running pressure, pressure plate pressure and time off the plate may be the cause of stencil blockage. Stencil openings are small, if the stencil edge burrs more, resulting in bad tin, will also lead to screen frame plugging.
3. Environmental factors
Solder paste plugged stencil and automatic solder paste printing machine operation temperature inside the machine, should consider the operating environment of the equipment.
4. Improper operation
The use of improper squeegee or operating practices are not standardized, such as the angle of the squeegee is not right, uneven speed, etc., may also lead to clogging.
II. How to avoid these problems?
SMT automatic solder paste printing machine before printing operations, the operator should check the following aspects.
1. Selection of suitable squeegee: generally metal or squeegee, depending on the product.
2. The printing pressure of the solder paste printing machine.
3. The squeegee speed, printing stroke, distance and position of the solder paste printing machine when printing.
4. The stripping method and speed of the printing machine.
5. The cleaning cycle of the solder paste printing machine: general automatic solder paste printing machine has dry cleaning, wet cleaning, vacuum cleaning and other options, the specific cleaning mode and cleaning method need to be set according to the product.
6. Mark point identification methods and stencil positioning.
7. Strengthen the operation of the training: training for operators to improve their use of equipment and maintenance skills to ensure that the operation of the standard.
8. Regular maintenance of equipment: regular maintenance and overhaul of the printing machine to ensure the stability of the equipment.
Description of NeoDen ND1 Solder paste printer
1. Simple and reliable PCB positioning system
Adaptive PCB board thickness, software tunable flexible side pressure and magnetic supporting device.
2. High stability CCD camera system
Four-way light source adjustable, with uniform illumination and the perfect image collection.
3. Intelligent scraper system
Programmable and independent direct-coupled stepper motor control, built-in precision pressure control system.
4. High efficiency stencil cleaning system
The new wiping system ensures full contact with the stencil, and the increased vacuum suction ensures that the solder paste remaining in the mesh is effectively removed, and the effective automatic cleaning function is achieved.