Calibrating steps/mm, do I need to build firmware?  

Re: Calibrating steps/mm, do I need to build firmware?

Hi Marten

Best way to calibrate feed is to change the "flow rate" setting in the slicer. Each filament type and even colour can be different (mainly depends on filament softness - how much the drive gear bites into the plastic).

If you really want precisely dimensioned prints, then you will have to take into account contraction of the plastic during cooling and environmental conditions during print and make allowances in the slicing.

Peter

Re: Calibrating steps/mm, do I need to build firmware?

It is only one axis which needs calibration. I believe it is the Y axis since the belt is much longer.

I really want to change the firmware and use the slicer parameters for differences in filament.

Re: Calibrating steps/mm, do I need to build firmware?

In that case, you will have to change the firmware.

Line 26 in Configuration.prusa.h:

#define DEFAULT_AXIS_STEPS_PER_UNIT {100,100,3200/0.8,174.2}

X, Y, Z, E

Peter

Re: Calibrating steps/mm, do I need to build firmware?

Which github repo should I use?

Re: Calibrating steps/mm, do I need to build firmware?

I believe it is https://github.com/prusa3d/Prusa-i3-Plus

Re: Calibrating steps/mm, do I need to build firmware?

Hi Marten

If you search my previous posts, you will find everything you need to know, including how to set up the Arduino IDE for the RAMBO.

Search my posts for "github", "repository" and maybe "Arduino". I think you will find everything you need to know, if not, post back here and I will be pleased to help further.

Peter

Re: Calibrating steps/mm, do I need to build firmware?

I have found these repos on github:
https://github.com/prusa3d/Prusa-Firmware
https://github.com/prusa3d/Orignal-Prusa-i3

The Orignal-Prusa-i3 contains a build.sh requiring the firmware to be in /home/arduino.

There is no /home/arduino/Prusa-i3-Plus/Firmware/variants, as required by build.sh. There is however a /home/arduino/Prusa-Firmware/Firmware/variants. There are four 1.75 mm variants in that directory. I have no idea which Rambo I have, I got it with the kit. Shipped in January.

The directory structure is a bit confusing to say the least 😮

Best regards

Mårten

Re: Calibrating steps/mm, do I need to build firmware?

For the variants: For new machines, you want:

1_75mm-RAMBo13a-E3Dv6lite.h

Filament size: 1.75 mm
Electronics: RAMBo Mini version 1.3a
Nozzle Type: E3D V6 lite

You can take the build.sh file from the "Orignal-Prusa-i3" repo and modify it accordingly for the newly created repo.

Re: Calibrating steps/mm, do I need to build firmware?

Thanks endaf.j!

Now I am stuck att arduino-cli. I have installed latest arduino (1.6.7) in my Ubuntu 64 bit, but there is no arduino-cli.

Mårten

Re: Calibrating steps/mm, do I need to build firmware?

I have put in a little bit of effort trying to understand the Arduino IDE and how to build new firmware. I don't need another hobby :-).

I belive that changing calibration parameters should be possible in the firmware itself. Not needing compilation of the source code. For now I am sticking with the default steps/mm. In a couple of months I will want to make prints with a better calibrated printer. Hopefully the firmware build process will be better documented, or configurable in firmware. Tuning feed rate while printing would be a nice thing don't you think?

Mårten

Re: Calibrating steps/mm, do I need to build firmware?

Hi Marten

Personally, I don't see why it would be necessary, once calibrated properly, for any real-time adjustment to be required.

Yes, I have measured a 100mm feed and adjusted accordingly in the firmware (the value is a compile-time constant - #define); yes it is possible to alter the feed rate via GCode, but this requires real-time floating-point calculations which are not the strongest point of an Arduino microprocessor. I prefer to leave this sort of tweaking to the slicer.

Peter

Re: Calibrating steps/mm, do I need to build firmware?

Ok, so gcode is in steps not millimeters? Sounds like good advice then. But how do I change that setting?

Re: Calibrating steps/mm, do I need to build firmware?

No, GCode is in mm. Any real-time adjustments involve additional calculations.

It's relatively simple to convert mm to steps, but add in a further calculation for "tweaks" creates a significant number of additional processor operations.

Remember, it is only a 16MHz processor...

Peter

Re: Calibrating steps/mm, do I need to build firmware?

Forget about tweaking in real time. I just want to change the X, Y and Z steps per millimeter to
X 99.8
Y 99.4
Z 4051

If I knew how I would gladly change this in slic3r.

Re: Calibrating steps/mm, do I need to build firmware?

Marten

Apologies, I can't remember all the individual queries and I don't have time to re-read all the threads I am posting on...

I have recently been referring to the extruding adjustments, which is not what you are looking to achieve.

In any event, have you had a look at the GCode wiki to see if what you are looking for can be done?

If not, then you will have to re-compile the code with the amendments according the my post on the previous page.

Peter

EDIT: looks like M92 command will achieve what you need. Should override the firmware settings. You can include this command in all gcode you generate or you may be able to save to eeprom.

Re: Calibrating steps/mm, do I need to build firmware?

PJR is absolutely right.

I actually reset the steps per mm for extruder in Slic3r start g-code with M92 E161.3, so you just change this constant 🙂

Re: Calibrating steps/mm, do I need to build firmware?

Yay!!! I got something right (at last...)

Thanks Josef!

Peter

Re: Calibrating steps/mm, do I need to build firmware?

Excellent! Thanks Peter and Mr. Prusa!

I will add this to my gcode:

M92 X99.8 Y99.4 Z4051
M500

Will the M500 save the values to EEPROM?