Sitaraman and Sizemore have shown with parametric FEM studies that reducing plated thickness from one oz to half oz thicknesses increases barrel stresses and decreases corner stresses. Experimental data gathered by Sleboda supported these modeling results, showing that holding copper elongation and hole radius constant, PTH reliability for corner cracking increases as plating thickness is decreased. I believe someone also published an article showing that manufacturing quality measures like waviness dominated plating thickness for PTH reliability over a certain parameter range, but I can't find the reference. So the answer depends I guess on where your failures are occuring. Cheers, Andy REFS: Sizemore, J. and Sitaraman, S. K., "Elastic-Plastic and Elastic-Viscoplastic Modeling of Plated-Through Holes in Solder Shock Test," HTD-Vol. 319/EEP-Vol. 15, Cooling and Thermal Design of Electronic Systems, Ed. C. H. Amon, SME International Mechanical Engineering Congress and Exposition, Nov. 12-17, 1995, San Francisco, CA, pp. 163-173. Sleboda, T. J. "A study of Plated Through Hole Reliability of Formaldehyde-Based Electroless Copper Depositions in Multilayer Board Productions, M.S. Thesis in Material Science, Georgia Institute of Technology, 1996. ---------- From: GeoFranck [SMTP:[log in to unmask]] Sent: Thursday, August 14, 1997 5:10 PM To: [log in to unmask] Subject: [TECHNET] Design: Half Oz Copper Colleagues, Are there any studies which measure the thru hole realiability of HALF Oz Copper vs ONE Oz copper? Thanks George Franck Raytheon E-Systems Falls Church Va