I searched but did not find this as a topic. Not sure if a new issue or just not brought up, or my search is not using the right words. Using Carbide Create v764.
The gcode created by Carbide Create v764 does not specify a feed rate when issuing a z command to raise or plunge at the ends of the tab, thus grbl uses the last given feed rate which is the feed rate defined for the tool. So if you have a 1/4 at a feed rate of 75 IPM and a plunge as 20, when reaching a tab it will raise and lower at 75 IPM instead of 20 IPM.Here is a sample of the gcode leading up to and over a tab: In the example I used a feed rate of 50 and a plunge of 1 to make the difference really obvious when watching it run.
G0X0.0000 Move to beginning of cut.
Z-0.3902 Lower Z
G1Z-0.5000F1.0 Plunge at 1 IPM to -0.5000 depth.
X1.6961F50.0 Cut right until beginning of tab at 50 IPM.
Z-0.3500 Raise Z to -0.3500 for tab height, no feed rate specified so last feed rate of 50 IPM is used.
X2.3211 Cut right until end of tab, no feed rate specified so last feed rate of 50 IPM is used.
Z-0.5000 Lower Z back to -0.5000, no feed rate specified so last feed rate of 50 IPM is used.
X5.0000 Continue cut to end.
Z0.2000 Raise Z to retract height, no feed rate specified so last feed rate of 50 IPM is used.