1. You need to get your laser's focal point as small as possible to get the finest detail when laser engraving photos. We use a 3" focal height with a 3 element glass lens and use a piece of black anodized aluminum to focus on. The black surface will not reflect the beam so it's easiest to see when it's the smallest. We then use a few dabs of hot melt glue between the lens thread and laser module/heat sink to secure the lens in place. It could move when engraving and cause undesirable results.
2. You need to set the velocity and accel the same as your X&Y axis, or the slowest axis will affect the others
3. Don't use S commands in Mach3. They will dwell because there for spindle speed in Mach3, not laser power. Edit your PP to use the PicConvert board and A axis depth commands. A0 to A-.0255. The J-Tech Vectric PP is for grbl, not Mach3.
4. The focal point determines the laser's burn line width. The Pixel Resolution setting in PicLaser sets the X&Y axis step over distance in the gcode file, so the laser's burn lines lay down next to each other without overlapping or leaving gaps between them. You will need to resize your image in the editor using Auto. The instructions are on Page 14 in the Tutorial that you can find with the Help button.
5. Every time you power up the PicConvert board, it will go to approximately 2.5v. I use negative A axis values to increase the laser power, so you will need to jog up the A axis to 0v, then zero the A axis. If you keep the PicConvert wall wart power supply plugged in, you should not have to do it every time unless it looses position and need to calibrate it to 0v again.
6. I recommend using negative A axis values to power up the laser higher to burn darker. Just think of the laser as a cutting bit. The laser can actually cut 3D reliefs in softer wood like Poplar. http://forum.darklylabs.com/index.php?p ... rave-pro-5
7. No 3 answered that question.
8, You have to get the focus, Pixel Resolution setting and feedrate just right to get the lower & upper shade range correct. Different each material it will require a trial & error period to get the settings just right.
We use a 3 for the step & dir pulse in Motor Tuning. Leave it at 5 if it does not give you any issues with the PicConvert board loosing steps/position.