Moving extruder offset


#1

I have been using octopi for a month now and i want to know if its possible to see the how far the extruder move or its coordinate, is it possible if i choose to move 100 mm in x axis, and due to connection issue it moves 100.1 mm or 99.9 mm, is there a log to see it? Thank you


#2

What printer are you using?


#3

And if you have connection issues then enable the serial log, print something and then provide the log.


#4

I'm using creality ender 3, i've been printing just fine, but just wondering if its possible to see the exact coordinate since maybe connection issue may cause a very tiny little bit of error that our eyes can't see when moving the extruder manually from the octopi.


#5

Can anybody help me with this? i've checked the serial log, but it only shows like move x 100 something like that, i need to know how precise the precision of my 3d printer for my research


#6

Remember this part? It's difficult to help others if they don't provide the logs when asked.


#7

I would say, the szenario you thinking about is more or less irrelevant.
If you move in X for 100mm this is one line of gcode command sent to the printer. The printer will receive this command and execute it - or it will not receive it (connection issue) and will not execute it - or the command gets destroyed through a connect issue and the printer maybe didn't execute it or make some crazy thing.
But i can't imagine a szenario where the 100mm mutate to 100.1mm or something else through a communication error.


#8

A line of Gcode will be sent to your printer. Something like G1 X100 F1800

Your printer firmware will convert the X100 value to a number of steps based upon its configuration. I believe the Ender 3 uses 80 steps/mm on the X and Y axis. So the firmware will pulse the X stepper motor 8000 times. I'm ignoring microstepping.

Will that result in a 100.00000 mm move as measured on the machine? Maybe. If your X axis is in perfect mechanical condition and the belts are not too tight or too loose or too worn and the hot end carriage isn't loose and the machine is properly calibrated to ensure that 80 steps/mm is the appropriate value and no steps were lost in processing the command.

If you simply want to see the coordinate where the machine thinks the nozzle is you can use the Gcode command m114. Example: Use octoprint to home you X and Y axis then issue these commands through the OctoPrint terminal tab:

G1 X0 Y0
M114

The response on my machine was
Recv: X:0.08 Y:-0.00 Z:0.20 E:0.00 Count X: 0.00 Y:-1.17 Z:0.20 E:0.00

Notice that X is not at zero. The machine firmware did that, not OctoPrint. Now I'll try a move to X=100 mm (which is not the same as a 100 mm move):

G1 X100 F1200
M114
Recv: X:100.00 Y:-0.00 Z:0.20 E:0.00 Count X: 99.92 Y:-1.15 Z:0.20 E:0.00

The machine knew my X wasn't exactly at zero and added enought steps for 99.92 mm to bring the nozzle to X = 100 mm. Is the nozzle exactly at X100? No way of knowing without breaking out measuring equipment. It is close enough for 3 printing :wink:


#9

Yeah i guess this is the most solutive answer, i also asked the same thing to my senior in electrical engineering and got similar answer to you, thanks for the enlightment