Flux paste key contains active agent, epoxy resin, thixotropic agent and organic solvent these components. The active agent in led lead free solder paste can efficiently remove the metal oxides of electric welding soldering parts, and can also reasonably reduce the lead and tin interfacial tension.
Organic solvents, on the other hand, can be stronger mixing, adjusting led no heavy metal solder paste proportionality. Solder powder is generally composed of tin, bismuth and silver alloy copper, etc., according to the proportion of the other area of the preparation and arrive at a better welding soldering effect. According to the different solubility requirements, the solder will also have hard and soft points. According to the customer’s requirements and application requirements of the solder can also be divided into blocks, rods, small pieces and flocculent and other styles. And the different materials and shape of the solder powder in the whole process of operation also stimulate their own unique role. After understanding the efficacy and composition of led solder paste without heavy metal, you need to be stronger to get the storage.
General conditions led solder paste in the unopened situation can be applied for 6 months, do not have to be placed in the light of the place.
The led lead-free solder paste to have good printing actual effect not only rely on the quality of led lead-free solder paste merit to manipulate, you also need to grasp the high efficiency led lead-free solder paste printing technicality.
I. Lead-free solder paste printing early preparatory work
1. Before printing the solder paste, we should check whether the stencil has deformation and whether the scraper has vacancies. The stencil and squeegee should be kept straight and clean, free of dirt and dust, to ensure that the lead-free solder paste is not easily damaged, resulting in the actual effect of spot soldering.
2. During the whole process of solder paste printing, try to have special tools to stabilize the PCB board, such as jigs or vacuum pump equipment to fix the bottom plate, to avoid PCB board deviation, and to enhance the separation of the stencil after solder paste printing.
II. Printing process
1. The PCB board and stencil should be changed to the best place, and the gap between the two should be the best. Because if the gap is large, it will cause solder paste leakage to the solder layer.
2. Lead-free solder paste in the beginning of the printing of that time to be appropriate to add, can not add too much or too little, the general situation of the A4 stencil for the first time to add 400g above and below the A5 stencil to add 200g above and below the B5 stencil to add 300g above and below.
3. When in the printing of the stencil paste slowly decreases, should be added to the appropriate paste up.
Ultimately, led lead-free solder paste printing is carried out after the stencil’s separation out slower is better. Solder paste in the continuous printing after the need to clean up the stencil waste dirt (adhesion of the paste), in order to prevent in the aftermath of the whole process of printing caused by the tin ball. If the solder paste is left for too long or stay on the stencil for too long, the printing characteristics and viscosity will be reduced, plus the drug mixing, can be improved. led solder paste printing workplace is best clean and sealed production plant, but also can regulate the ambient temperature of the workplace. Then the viscosity of the paste can not be due to the evaporation of the drug and affect the actual effect. led lead-free solder paste printing work is over, should be cleaned up the stencil neatly, easy to the next application.
Company profile
Zhejiang NeoDen Technology Co., LTD., founded in 2010, is a professional manufacturer specialized in SMT pick and place machine, reflow oven, stencil printing machine, SMT production line and other SMT Products. We have our own R & D team and own factory, taking advantage of our own rich experienced R&D, well trained production, won great reputation from the world wide customers.
We believe that great people and partners make NeoDen a great company and that our commitment to Innovation, Diversity and Sustainability ensures that SMT automation is accessible to every hobbyist on everywhere.
Post time: Nov-29-2024