How to calibrate a Reprap.

To help some people asking for help, I offer this quick start guide to get calibrated. I will eventually put this in the wiki once it's all worked out and proven, and peer reviewed.

From the wiki-
[reprap.org]

I have tried this method but it seems unreliable for me. Either due to sloppy z creating inconsistent measuring points, or backlash giving bad prints to start with.

This is my method.

With everything powered on and working in there right directions. I suggest having the print bed and extruder installed.

1. Raise the Z a few cm to allow the bed and nozzle to move freely.
2. Adjust the Y end-stop far back enough that the bed carriage doesn't hit the frame but stops very close to it. This gives you the max print space.
3. Order the Y home.
4. On the open side (away from the end-stop) use digital calipers open them long enough to press one end against the bed carriage the other firmly pressed against a non-moving part of the frame. I.E. the nut next to the fender washer. If your calipers cannot reach, order the bed to move closer.
5. Once you have a good position on the calipers zero it out (should be a zero button).
6. Remove calipers.
7. Order the Y bed to move +100mm.
8. Gently place the calipers in the exact same position as before and measure the difference. Record the distance moved vs the distance ordered. (Might be a negative number).
9. Return the bed to home.
10. Repeat steps 4-9 until you get consistent data.

Measuring the X axis is very similar save for where you place the calipers. Where ever you choose to measure from make sure it is a part you can press the calipers against firmly with out breaking anything. Record the distance moved vs the distance ordered.

For the Z axis ensure the X axis is level. That means the same distance from the Z motor couplings to the top of the X motor/idler nut capture.

Then measure the distance from the Z motor coupling to the top of the Z idler/motor mount. Move the Z up 10mm and measure again. Repeat the same steps as before. Record the distance moved vs the distance ordered.

Now with your new numbers, should look something like "X 93.402/100, Y 98.113, Z 102.552/100"

View the file you last used to load your firmware and find the current steps per mm for each axis.

Divide the mm ordered by the actual mm moved then multiply that by the number of steps in your firmware. The result is your new steps per mm.

Example, X- "(100/93.402)*500=535.3204428170703"

Don't be afraid to use all the decimal points you can. It can only serve to give you better results.

Take this new number and use it in place of your old steps per mm for that axis.

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-John, San Diego, CA

www.youtube.com/user/GeoDroidJohn

MrJohnEcker on Twitter, Gmail

Hello I almost finish my calibration but it seems to build bigger things, and the z is not proportional to x and y. I don´t know where to change the number of steps,
I can´t acceso the firmaware on my repolicatorg it automatically uploaded it. WHere should I change what and what?

Thanks for the help I liked your post bit is just missin that to be perfect!

I think ReplicatorG is host s/w (on the PC, not the firmware in the printer electronics)
Calibration values must be either loaded to the firmware or the firmware recompiled with altered constants in the source.
Fortunately most recent firmwares seem to allow dynamic loading from the Host. (like the Repetier host and firmware I am using)
If you identify your firmware, you should be able to search for documentation on how it handles changing configuration..

If google can't find references to your software, then back here you might shorten the response times a bit if you were to save a wee template of information on your setup, something like below, and include it with such questions.

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Printer type: (e.g. Prusa Mendell, etc)
Variations from "standard": (bearings, belts etc)
Control s/w (on host (PC): (e.g. Pronterface, Repetier etc) and Version#

Printer electonics type: (e.g. RAMPS, Sanguinololu, GEN? )
Firmware on printer: (e.g. sprinter, Marlin, Repetier etc) and Version#

Extruder type:
Filament type: (PLA or ABS)
Filament size: (e.g. 1.75mm, 2.8mm, 3mm)

Heated bed: (Y/N)
Build surface( e.g. glass, blue tape, PET etc)


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