I. Stencil printer types
A manual printer is the simplest and cheapest printing system. PCB placement and removal is done manually, the squeegee can be used by hand or attached to the machine, and the printing action is done manually. PCB and steel plate parallelism alignment or edge of the board to ensure the position are dependent on the operator’s skills, so each printed PCB, the printing parameters will need to be adjusted and changed.
2. Semi-automatic printing machine
Semi-automatic presses are currently the most widely used printing equipment, they are actually very similar to manual presses, the placement and removal of PCBs still rely on manual operation, the main difference with the manual machine is the development of the printing head, they can better control the printing speed, squeegee pressure, squeegee angle, printing distance and non-contact pitch, tool holes or PCB edges are still used to position, while the steel plate system to help personnel Good completion of the PCB and steel plate parallelism adjustment.
3. Fully automatic printing machine
The solder paste is printed on the pads of the components on the base board, but nowadays the size of the surface-mounted components is getting smaller and finer, so the design of the circuit base board is correspondingly smaller and finer. Therefore, the accuracy and efficiency of the solder paste printing has to be greatly improved. Nowadays, most of the electronic product manufacturers are using automatic or fully automated solder paste printing machines to produce SMT products, and PCB placement is done by edge-bearing conveyor belt, with process parameters such as squeegee speed, squeegee pressure, printing length, and non-contact pitch all programmable.
PCB positioning is done by using positioning holes or board edges, and some equipment can even use vision systems to align PCB and steel plate parallel to each other, which eliminates the errors caused by edge positioning when using such vision systems, and makes positioning easy, with manual positioning confirmation replaced by vision systems. The newer solder paste printers are equipped with video lenses to monitor the printing situation and make corrections at any time.
II. Stencil printer maintenance
Remove the squeegee, use special wipe paper dipped in anhydrous ethanol, wipe the squeegee clean, and then installed in the printing head or received in the tool cabinet.
Clean the stencil, there are two methods.
Method 1: Washing machine cleaning. Washing equipment with the template, the cleaning effect is the best.
Method 2: Manual cleaning.
Use special wipe paper to apply anhydrous ethanol, the solder paste will be cleared, if the leak hole blockage, available with a soft toothbrush, do not stab with a hard needle.
Use compressed air gun to blow the residue in the leakage hole of the template clean.
Put the template on the paste loading machine, otherwise receive it in the tool cabinet.
Post time: Feb-24-2022