Rosin is the extruder barrel of auxiliary equipment, extrusion solder wire is a vital link, due to lack of experience, the need to open the lid frequently used view usage or with many years of experience in the case of estimating rosin used up, or to produce more or less trouble. Occasional visual rosin barrel out, set in the middle of rosin barrel belly visual plexiglass, for the first time anywhere in the use of rosin can understand the situation, and the first time to add the required rosin flux, so that smooth production , to avoid the work of the extruder rosin-break situation.