In the PCB electroplating process, there is often a bad phenomenon of spraying paint on the coating, which is due to oil pollution on the surface after electroplating, resulting in poor adhesion. However, when electroplating parts, there are often pinholes after plating. Today, sayfu talk about pinholes and treatment solutions caused by improper pretreatment.
FAQ of PCB electroplating
Parts in addition to oil is not complete or improper storage during machining, dust falls on the surface, placed for a long time, dust and grease are mixed together, it is difficult to remove clean, so as to form not obvious small oil spots, bubble retention on the formation of pinholes when plating.
When polishing parts, abrasive, polishing paste and other embedded in the surface of the small pit, it is difficult to clean, the pit can not deposit on the coating and produce pinholes.
Parts pickling rust removal is not complete or pickling time is too long to produce corrosion, the surface is scattered with carbon rich points, plating coating can only be deposited around these non-conductive particles and form pinholes.
Treatment methods
The reasonable pretreatment process, to ensure the quality of pretreatment, the pretreatment process for: parts on to chemical degreasing, hot water washing to water washing, pickling – two water washing – electric lift oil to hot water to wash, wash water – weak corrosion – two water washing, strictly carry out operation procedures, strengthen bath maintenance management.
Before plating parts surface unclean, such as oil dirt particles and other non-conductive particles adhesion. Usable alkali water wetted brush, and then remove oil, small parts had better be rolled light processing.
Chemical oil removal or electrochemical oil removal tank liquid surface oil layer, should be timely fishing out. The polished parts should be removed completely.
The pickling time must be well controlled. Once the rust is removed, it should be removed and cleaned immediately. In order to prevent the parts from over-corrosion, a certain amount of corrosion inhibitor should be added into the acid washing solution.
