Hi Vic One problem you will encounter is "boiling" the flux out of the solder paste and launching solderballs everywhere. A controlled preheat ramp prevents this from happening. Dave Hillman Rockwell Collins [log in to unmask] ______________________________ Reply Separator _________________________________ Subject: Changing of reflow profile. Author: [log in to unmask] at ccmgw1 Date: 7/1/96 10:20 AM Hi, I am a student doing research at the temperature issue during the IR reflow process. As I know that there is a well-defined temperature profile for the PCB when passing through the oven. I just wonder if it is possible to forget all the preheat, ramp up periods and go straight into the spike zone where solder paste will melt at that temperature? What are the potential problems I have to face in this context, excluding the thermal mass issue? Any input is appreciated. Thanks in advance. Vic. [log in to unmask]