Causes of tin short circuit in wave soldering and its adjustment
2021-04-12 Classify: FAQ Author: 广晟德 Browse: 3108
The short circuit of connecting tin in wave soldering is a common problem in plug-in production of electronic products. It is also a common trouble caused by wave soldering fault. There are many reasons for connecting tin in wave soldering. If we want to adjust wave soldering to reduce connecting tin, we must find out the reason of connecting tin in wave soldering and then deal with it, Guangshengde wave soldering is here to share with you the reasons and adjustment methods of wave soldering.
Cause analysis of tin short circuit in wave soldering
1. The flux activity is not enough; 2. The wettability of flux is not enough; 3. The amount of flux coating is too small; 4. Uneven coating of flux; 5. The PCB can not be coated with flux locally; 6. There is no tin in the PCB area; 7. Some pads or legs are seriously oxidized; 8. The wiring of circuit board is unreasonable (the distribution of components is unreasonable); 9. The direction of walking board is wrong; 10. The content of tin is not enough or the content of copper exceeds the standard[ The melting point (liquidus) of liquid tin increases due to the impurities exceeding the standard; 11. The foaming tube is blocked and the foaming is not uniform, resulting in uneven coating of flux on the circuit board; 12. The setting of air knife is unreasonable (the flux is not evenly blown); 13. The walking speed and preheating are not well matched; 14. The operation method of hand tin dipping is improper; 15. The inclination angle of the chain is unreasonable; 16. The crest is uneven.
Adjustment method of tin short circuit in wave soldering
1. The flux is not enough or uniform, increase the flow rate;
2. Lianxi speed up and enlarge the orbit angle;
3. Don't use 1 wave, use a single wave of 2 waves, the height of tin is not necessarily 1 / 2, just touching the bottom of the plate is enough. If you have a tray, the tin side is on the highest side of the tray;
4. Whether the board is deformed;
5. If the 2-wave singles are not good, use 1-Wave punch, 2-wave hit low to touch the pin, so that you can repair the solder joint shape and get it out;
In view of the above reasons, you can also check whether the wave soldering machine has the following problems that lead to the short circuit of wave soldering tin:
First wave crest height distance;
Whether the second chain speed is appropriate;
The third wave soldering temperature;
Whether the tin quantity of the fourth tin furnace is enough;
Whether the fifth peak is symmetrical or not.
Because soldering tin by wave soldering can cause PCB short circuit, it must be repaired before it can be used. The repair method is to first apply a little flux (i.e. rosin oil solvent), and then heat the soldering tin position with high temperature ferrochrome to melt it. The soldering tin position will retract under the action of surface tension and no longer short circuit