Firstly can you advise me on the existence of the ANSI/J-STD-011 Secondly has anyone any information on the "potato chip effect". As far as I can gather it is the stretching of the laminate caused by the impact of the abrasive scrub used in the preparation of innerlayers for photoresist. I have recent;y come across a PCB assembly with a warpage which I am trying to determine it's cause and I am trying to eliminate the potato chip effect. Also note, when I baked the assembly, it somewhat removed the warping of the board. Can anyone comment on my situation and help me understand the potato chip effect and problems it causes if present on an assembly board. Thanks in advance Moss Dore AMT [log in to unmask]