The primary reason is the problem of crest furnace equipment: at present, solder bar the design of some lead-free solder strip crest furnace on the market is not ideal, the crest is too high, the peak is too wide, the double crest furnace is too close and the selection of rotary pump. When the wave crest is too high and the solder falls from the peak, the temperature reduction error is relatively large. The solder mixes with air and rushes into the tin furnace to form oxidation and semi-dissolution phenomenon, leading to the occurrence of tin slag. Rotary pump did not do a good job of preventive measures, constantly press tin slag into the furnace, ring chain reaction excited tin slag occurred.

The temperature of wave soldering of lead-free solder strip is generally controlled to a relatively low level, generally 280℃±5℃ (for lead-free SN-CU0.7 solder strip), and this temperature is the basic requirement to achieve the temperature in the welding process, low temperature can not achieve a good dissolution of tin, directly form tin slag too much. In the case of manual operation, it is also very crucial to add lead-free solder strips at the right time. The appropriate time to add tin strips is to always keep the distance between tin surface and peak short; Is there often finishing the tin slag, so that the peak of the fall of the solder can enter the furnace as soon as possible, but not in the tin slag above, uneven heat, will also form tin strip tin slag too much; The cleaning furnace is also very crucial at ordinary times. If there is no cleaning furnace for a long time, the impurity content in the furnace is high, which is one of the reasons for too much tin slag in the lead-free solder strip. Therefore, the wave furnace to regular cleaning, that is, the wave soldering tin all sorted out, clean each part of the tin furnace, and then installed each part, add a new lead-free solder bar.