Finished profiling this morning for a particularly obstinate board. Couldn't raise the nozzle as many of you suggest, and SRT promotes, because of dense population around every associated rework part. However, we did get good removes (TC'd and verified), raised the place and reflow time/temp profile to 275/250/55/15 for top, bottom, reflow, and additional reflow.
This profile worked for all but two parts on the board. The 183 times just touched 100 seconds, 205 times at a little less than 45 seconds, and an overall delta of about 10 degrees C. with TC's in all four corners on remove.
I now want to know how many of you have the new nozzles not requiring lifting off the board surface. If you do, how do they work. I have ordered a sample for test but will not receive it for another week. Any tips on the new 40mm, especiall, are apreciated.
Also, I have given up on worrying about the force settings without mechanical feedback to the computer. If 0 = 35 grams, so be it. I'll do some other modifications if lesser force is required especially when pasting.