Definitely not on every panel, for exactly the reasons you describe. One step is taken on the first panel/layer for every job, to determine proper exposure. A good developer filtration system will help (although not eliminate) redeposition of partially polymerized resist. Trimming the step tablet to the minimum exposure range also reduces the amount of unwanted resist. Mark Dowding Multek, Irvine ______________________________ Reply Separator _________________________________ Subject: Re: C A Picard Exposure Frames Author: [log in to unmask] at INTERNET_GATEWAY Date: 10/2/96 12:16 PM > IMO, once per day or even once per shift is not frequent enough. > There are too many variables that affect exposure; hold times > after lamination, artwork density, developer changes, just to > name a few. We take our steps on every job. By every job, do you mean on every panel? Remember that step tablets result in partially polymerized resist which can come off the board and contaminate your developer solution. You should keep the number of tablets run to the minimum necessary to avoid redeposition of resist particles. *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ***************************************************************************