With the rapid development of technology and the improvement of living standards in China, SMT processing is not only a comprehensive system engineering technology, but also a complex process, which brings too much convenience to operators. So what are the common problems of SMT processing? With Xiaoxun, let's take a look at the introduction of "the daily faults of SMT processing and the scope of processing technology".
What problems often occur when SMT processes solder paste printing
Solder paste printing is a complex process in SMT patch processing, which is prone to some defects, affecting the quality of the final product. Therefore, in order to avoid some common faults in printing, the following is to introduce SMT process solder paste printing common shortcomings to avoid or solve the problem:
1. Punching, usually after printing, solder paste on the solder pad will be hilly.
Cause: It may be caused by the clearance of scraper or too high viscosity of solder paste.
Avoid or solve: SMT patch processing appropriate to reduce scraper clearance or select the appropriate viscosity of solder paste.
2. The solder paste is too thin.
Causes: the template is too thin; scraper pressure is too large; solder paste fluidity is poor.
Avoid or solve the problem: select the appropriate thickness of the steel mesh; select the appropriate particle size and viscosity of solder paste; appropriate reduction of scraper pressure.
3. After printing, the thickness of solder paste on the pad varies.
Causes: solder paste mixing and uneven, making the particle size is not common; template and PCB are not parallel.
Avoid or solve: mix solder paste fully before printing; adjust the relative orientation of template and PCB.
4. Different thicknesses with burrs in the margin and appearance.
Cause: It may be that the paste viscosity is low and the hole wall of the template is rough.
Avoid or solve: select solder paste with slightly higher viscosity; check the etching quality of template hole before printing.
5. Collapse means that after printing, solder paste sinks to both ends of the pad.
Causes: too much scraper pressure; improper positioning of PCB; too low solder paste viscosity or metal content.
Avoid or solve: adjust pressure; fix PCB from scratch; select solder paste with suitable viscosity.
What Are the Scopes of SMT Processing Technology?
SMT is a comprehensive system engineering technology, which covers the baseboard, design, equipment, components, assembly process, production accessories and management, etc. SMT equipment and SMT process require stable voltage on the operation site, to prevent electromagnetic interference, to prevent static electricity, to have good lighting and exhaust emission facilities, to have special requirements for operating environment temperature, humidity, air cleanliness, and so on. Operators should also undergo professional technical training.
Reflow soldering: It is defined as the connection of surface mounted components and PCB pads by melting solder paste first distributed to PCB.
Wave soldering: The melted solder is sprayed by professional equipment to form the required solder peak. PCB with electronic components is connected with PCB pad through solder peak.
SMT surface assembly technology is a group of technology-intensive and knowledge-intensive technology groups, involving the packaging of components, circuit board technology, printing technology, automatic control technology, brazing technology, physics, chemical industry, new plastic materials and other specialties and disciplines.
The key of surface mounting technology depends on three factors: the equipment used, that is, the hardware facilities of SMT; the assembly process, the software technology of SMT; and the electronic components, which are not only the foundation of SMT, but also the driving force for the development of SMT industry.
The above introduction about "what problems often occur in SMT processing solder paste printing" and "what areas are involved in SMT processing technology" hopes to help you understand "the daily faults of SMT processing and the scope of processing technology".