I believe design complexity is a combination of 1. Component Selection * Number of leads/pads * Number of components * Type of components. For example: 0402 vs 1205, 15 mils vs 25 mils QFP 2. PCB design (Layout) * Number of Layers * Number of vias * PCB Area * PCB Fab. * Design rule violation * Poor design practice 3. Process Conformance * Equipment Compatibility * Process Compatibility (flux, cleaner...etc.) 4. Mechanical Assembly * Boothroyd Dewhurst DFM approach - Number of parts, screws - Cycle time to assemble Check out the following reference too! - 1983 Boothroyd Dewhurst Hand book - 1985 GE, Hitachi, Assembly Evaluation Manual - 1989 TI (Defense System) DFM program development - 1992 IBM Austin Design for Manufacturability Report Card - 1994 HP framework on launching DFM/A Hope that helps, Michael Yuen ---------- From: DAVID C WEBER To: [log in to unmask] Subject: Re: [TN] Design Complexity