I was asked to informally survey PCB shops as to how they control things like temperature, humidity, particulate count, general housekeeping (ie. visible accumulation of dust) etc. in various parts of thier operation. The idea is that we potentially upgrading our facility and want to get an idea of what is felt necessary for yeild purposes out in Industry. We're a relatively small volume, high mix shop (captive house) looking at production capabilities in the 5mil lines/spaces range. The areas of interest are: Photo & Shop Check; Layup; Lamination; and Plating/chemical processing. Any guidance/comments would be appreciated. Thanks, Jim Maguire Principal Engineer, E/E M&P Boeing Defense & Space Group [log in to unmask]