Z-axis feed rate

[Richotech]

Hi All,

I have a small engraver and need to have a slower feed rate on the z-axis as compared to the X and Y. I'm using a fine tip cutter on circuit baords and the tip is breaking off due to the z-axis driving the tip down too fast. Mind you I may need to slow the X-Y table down also. Is it easy to slow the z-axis while keeping the other two feed rates unchanged ?.

Brett.

[ger21]

If you're g-code contains the feedrate, you can change it there. Or, you can lower the Z velocity in the motor tuning screen. Doing this will slow you're rapids, though.

[Richotech]

Thanks Gerry,

I am using Eagle to make PCB's and the G-code converter for that allows separate X-Y and Z feed rates, but it does not seem to apply them to the z-axis ie. the feed rate is placed all through the code but only shows the faster X-Y feed rate.


Brett.

[Switcher]

Can you post a sample of your g-code file, as a .txt file?

I've never seen code from eagle, is it standard g-code? If so, you could use the Replace option, in Win. Notepad, then go back & edit the header & footer g-code by hand.

[mcphill]

Are you using PCBGcode? If so, I know for a fact you can have a different Z feed from XY. Sounds like you might not have something configured correctly.

[Richotech]

Hi mcphill,

Thanks for your help. I am using pcb-gcode. and I have set different feed rates for X-Y and Z, but like I said it isn't coming up in the final code. I also notice the drill G-codes don't have any Z-axis code at all !. I have set it to use the Mach config, but maybe I'm have missed something.

Cheers.

[Richotech]

Hi Switcher,

I have attached a sample of of code. The full code is over 26000 lines so I cut it down to two pages. The feed rate only ever shows the X-Y rate.

[James L]

I have had better luck loading PCB gcode files into Mach's Lazycam editor and making changes there. Took a little practice but I liked the control I had over how the programs turned out.

[mcphill]

Originally Posted by Richotech Hi Switcher, I have attached a sample of of code. The full code is over 26000 lines so I cut it down to two pages. The feed rate only ever shows the X-Y rate.

As a work-around, you could open the file in Notepad. Use "Find/Replace" (Ctrl-H) and search for "Z-0.2000" and replace with "F20 z-0.2000".

That will replace all your Z movements with a statement to slow the feed, do the Z move, and put the speed back up (the F2000.0 will stay on the original line.

Hope that helps!

I do a lot of "Find/Replace" on my files as I usually don't pay much attention to feed rates in my CAM program, and massage them once I am at the machine and "see how things" go.

As mentioned previously, you can also "speed limit" the Z axis in MACH3 itself, but that will limit the up travel as well as the down...