# Can I adjust print speed on the fly?

I am running an Ender 3 pro with an Octoprint connected. I accidentally set the print speed too slow in Cura and the print will take very long. Is there a Marlin command I can issue to the printer to speed it up without stopping the print?

You can use the M220 g-code like

M220 S200

to speed up your print speed to 200%.

You can simply enter this g-code command in OctoPrints "Terminal" tab at any time.

• Is there a way to set it too a certain mm/s I know I am splitting hairs but I have tried to experiment with that too. This will work for now though so thank you Nov 6 '20 at 13:54
• Not directly - since you may have different speeds for printing moves, travel moves, first layers, perimeters etc. Theoretically, you could alter the maximum feedrates with M203 to your desired speed, and push the feed rate multiplier up to its limit (990% as far as I can tell). Then all moves should run close to the mm/s speed you set with M203, but that approach doesn't seem very robust to me.
– towe
Nov 6 '20 at 14:05

# yes

Print speed is a setting that can be altered by just turning the click-wheel of the Ender 3. You don't need to push it to gain access to menus. A turn to the right does increase the speed, left lowers it. It is applied only some moments after stopping the turning - then the firmware does inject a M220 command as the next line. This means the current running movement is ended with the last set speed, the new speed is set and the following command will be done with the new speed.

As towe correctly states, one can also send a M220 command to the printer via a terminal, but then you need to have one set up before the print starts, as plugging in a terminal will reset your printer and abort the print!

• I believe it's applied after the current movement buffer has run empty, i.e. at the same point as canceling the print without M112 would stop the printer. That could be minutes at slow straight first layers; or fractions of a second for high-speed curved paths.
– towe
Nov 6 '20 at 8:39
• @towe partially correct: it takes stopping the wheel for a second or two for the firmware to decide "new speed is set... now I apply it" Nov 6 '20 at 9:56
• Are you sure about that? I couldn't find any such delay in a short code search: github.com/MarlinFirmware/Marlin/blob/2.0.x/Marlin/src/lcd/…
– towe
Nov 6 '20 at 10:04
• @towe I am rather sure from practical testing: turning the knob to 250 on a rather speedy baseplate did not affect the print for at roundabout a second, using a Marlin 1.9 design. Nov 6 '20 at 10:06
• @Jackie that's a crucial information! Nov 6 '20 at 15:17