PCB007 Magazine

PCB007-Feb2021

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82 PCB007 MAGAZINE I FEBRUARY 2021 When producing PCBs, we follow IPC stan- dards for Qualification Performance and Ac- ceptance from design, through production, to customer incoming inspection and accep- tance. However, there is oen one way of writ- ing a standard and a different way of interpret- ing it. Today I will attack a loophole that does not exist, yet is still used by many. Let's dig into the term "workmanship" as written in IPC-6012E 3.3.10, which represents the Qualification and Performance Specification for Rigid Printed Boards. You find the same section in IPC-6013 and IPC-6018. e requirement says: IPC-6012E 3.3.10: Workmanship Printed boards shall be processed in such a manner as to be uniform in quality and show no visual evidence of dirt, foreign matter, oil, fingerprints, tin/lead or solder smear transfer to the dielectric surface, flux residue and other contaminants that affect life, ability to assemble and serviceability. Visually dark appearances in non-plated holes, which are seen when a metallic or non-metallic semi-conductive coating is used, are not foreign material and do not affect life or function. Printed boards shall be free of non-conformances in excess of those allowed in this specification. There shall be no evidence of any lifting or separation of platings from the surface of the conductive pattern, or of the conductor from the base laminate in excess of that allowed. There shall be no loose plating slivers on the surface of the printed board. Are We Misinterpreting the Standards? A typical understanding of this requirement is oen limited to "no visual evidence of dirt, foreign matter, oil, fingerprints, tin/lead or Attacking the Loophole That Does Not Exist The PCB Norsemen by Jan Pedersen, ELMATICA

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