Is there a default feedrate for the zhop/lift during a firmware retract? I'm wondering if that feedrate has a bearing on the size of the blob left behind following a retract and if it can be tuned at all? Smoothieware has a Q parameter to the M207 command that seems to allow this to be configured. I had a quick look in GCodes2.cpp, but M207 makes no mention of the Q parameter so I'm assuming it's not supported in RRF.
The RetractFilament() function in GCodes.cpp has the following section:
// Set the feed rate. If there is any Z hop then we need to pass the Z speed, else we pass the extrusion speed.
const float speedToUse = (retract) ? retractSpeed : unRetractSpeed;
moveBuffer.feedRate = (retractHop == 0.0 || retractLength == 0.0)
: speedToUse * retractHop/retractLength;
moveBuffer.coords[Z_AXIS] += (retract) ? retractHop : -retractHop;
but I can't see where the Z speed is being passed as per the comment.
It would be nice to have in the firmware as it would be another setting to play with during a print for fine tuning.
See DC42's answer here: https://www.duet3d.com/forum/thread.php?id=1156
Completely missed that, thanks!