SMT placement processing, through rate is called the lifeline of the placement processing plant, some companies must reach 95% through rate is up to standard line, so through rate of high and low, reflecting the technical strength of the placement processing plant, process quality, through rate can improve the company’s capacity efficiency, reduce production costs, Z is important to be able to delivery stability, enhance customer satisfaction.
Definition of straight-through rate
The rate of reaching the shipping standard at one time.
Straight-through rate (First Pass Yield, FPY) specifically means: the number of good products that have passed all tests the first time the process is put into 100 sets of PCBs in the production line. Therefore, after the production line rework or repair to pass the test products, not part of the straight-through rate calculation.
What factors affect the straight-through rate
1. materials (including various electronic components material in the early stage, also including PCB boards)
2. solder paste
3. the quality and mentality of employees
How to optimize and improve the straight-through rate
Straight-through rate is related to the profitability and lifeline of the enterprise, so each chip factory is grasping the optimization and improvement of the straight-through rate, 100% certainly can not reach, but also hope to have more than 98%.
Therefore, you can improve the straight-through rate through some of the following links.
1. Optimize the pcb board stencil design
More than 70% of the welding quality in the solder paste printing process, which is the SMT industry summed up the experience data, solder paste printing is smt Z front process process, solder paste offset, pull tip, collapse, in many cases is the stencil design defects, stencil may be too large / small openings, stencil hole wall rough, etc. will cause the above-mentioned bad, which leads to pcb pads on the paste is bad, resulting in welding Bad, thus affecting the straight-through rate.
2. Choose the right type of solder paste
Solder paste is a mixture of a variety of metals and fluxes, similar to toothpaste, solder paste is divided into 5, 3 and other different types of solder paste, different products need to choose different solder paste for printing.
Detailed article about solder paste
SMT chip processing in which types of solder paste, storage and use of the basic understanding of the environment
3. Adjust the SMT printing machine squeegee angle, pressure
Printing machine scraper pressure, angle will affect the factors of solder paste, the pressure is large, it will cause less solder paste, and vice versa, the angle Z good is 45-60 degrees range.
4. Reflow oven temperature curve
According to the different products, adjust the preheating time, reflow temperature curve, using the furnace temperature tester, close to the actual temperature of production, and then get the furnace temperature curve, and then adjust the furnace temperature curve, so that the furnace temperature curve in line with the solder paste and product soldering requirements.
Post time: Feb-17-2022