Z axis calibration

Hi,


I'm trying to calibrate my mendel 90 but it isn't going well.
If i want start printing, the z axis goes down en keep lowering even if the extruder is on the heatshield.
Does anyone know how i need to solve that?

Thank you

3design

Sounds like the z axis isn't homing correctly. When you tell the axis to home does it move towards the endstop?

My mendel 90 has an endstop on top of the frame, the home position is good but if i start a print, the z axis lowers and it doesn't stop when it is on the glass plate, i think that the printer doesn't know how high the heatbed is but i don't know how i need to install that.

For the sturdy version you will need to change the Z steps per mm in the config file for 1.25mm pitch as the kits use 1mm pitch leadscrews.

After that follow the calibration instructions in the manual for the kit (on Github).

Edited 1 time(s). Last edit at 01/12/2014 08:15AM by nophead.

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[www.hydraraptor.blogspot.com]

Sounds like you need to tell the firmware to home at the top. You should also check that your gcode is homing before it starts to print

is there a video that i can see how i need to calibrate a mendel90 becase i don't understand how i need to do it.

i' ve found a video but in that video they adjust something in a arduino file and i can't find this file.
does anyone know which file this is?
[www.youtube.com]

It is in the Marlin folder and named Configuration.h

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

Is this the file from github?

How can i open a github file in arduino?

Use the following method once to set-up Arduino:

1. Open your web browser and go to [github.com]
2. Click on the "Download ZIP" button
3. Copy the "Marlin-Marlin_v1\Marlin" folder from the zipfile to "My Documents\Arduino"
4. Copy the "My Documents\Arduino\Marlin\Melzi" folder to "My Documents\Arduino\hardware"

Use the following method to modify the firmware:

1. Start Arduino and load Marlin from the "File|Sketchbook...|Marlin" menu entry
2. Locate Configuration.h and make your changes
3. Save Configuration.h and click the Upload button to compile and upload to the printer

Regards,
Neil Darlow

Edited 4 time(s). Last edit at 01/15/2014 03:54PM by neildarlow.

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

thank you, i'm going to try that

I've adjust the value from each motor, is there anything else that i need to adjust?

Quote
3Design
I've adjust the value from each motor, is there anything else that i need to adjust?

The only steps/mm value you should have changed should be the Z one (for the 1.25mm threaded rod pitch). After that you need to follow the Calibration section of the Build Manual which will walk you through the Z height and Extruder steps/mm setting procedure.

The Mendel90 Build Manual is here in PDF format. This is for the Dibond model but the testing and calibration sections are still relevant.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

What do you mean with the z height? I don't understand that. I think thaht that is the problem with my mendel90.

The Mendel90 has a limit switch for the Z axis located on the top-left rod mounting bracket.

You must set the height at which this switch operates in the Marlin firmware so it can calculate the zero position of the Z axis. If this value is set too large the zero position will be under the bed surface and if it is set too small the zero position will be above the bed surface.

The Build Manual advises that you should place a known-size object on the bed and nudge the print head downwards until the nozzle just touches the top surface of the object. You can then ask the firmware where it thinks Z is (M114) and use the known-height of the object and this value to determine the amount of adjustment to Z height that is required.

If, for example, your object is 20mm high and M114 tells you the nozzle is at 21mm then you need to add 1mm (minus 0.2mm to allow for nozzle expansion - so 0.8mm) to the firmware Z height value to lower the reported position. You then reload the firmware with this new Z height value and repeat the test to assure that M114 returns the correct height (plus 0.2mm).

This procedure, along with Extruder steps per mm calibration, is necessary to get you near the correct first layer height. Later you will measure the first layer thickness of a real print and adjust the Z height value again so that the first layer height is accurate.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

where in the marlin do i need to adjust the steps/mm?

In Configuration.h line 187:

// default settings
#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,200*16/1,E_STEPS_PER_MM} // Mendel90 with Wades and Stoffel15 bolt

The expression 200*16/1 represents the number of steps per mm for the 1mm pitch threaded rod.

You need to change this expression to 200.0*16.0/1.25 which is the value required for a 1.25mm pitch threaded rod.

I am correct in assuming your machine is actually the "sturdy" (or wooden frame) variant?

N.B. I am being technically correct here in modifying the expression to floating point. The #define is used to initialize an array of float values.

Regards,
Neil Darlow

Edited 2 time(s). Last edit at 01/16/2014 02:43PM by neildarlow.

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

If i move my z axis 50 mm with pronterface moves it 62,50mm.
Do i need to adjust the 200 to 128?

when i try to upload the firmware i get this eror code:

error oops! make sure you have sanguino selected from the tools ->boards menu

is there someone in Belgium that wants me to help to calibrate my mendel90???

Quote
3Design
If i move my z axis 50 mm with pronterface moves it 62,50mm.
Do i need to adjust the 200 to 128?

No, the change of the divisor from 1 to 1.25 in the expression will correct that for you.

Quote
3Design
when i try to upload the firmware i get this eror code:

error oops! make sure you have sanguino selected from the tools ->boards menu

That is my fault, I should have included in my inital Ardiuno set-up list the following:

• From the "Tools|Serial Port >" menu choose your COM port
• From the "Tools|Board >" menu choose "Melzi W/ ATmega1284p 16mhz"

It will then upload correctly.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

From the "Tools|Board >" menu choose "Melzi W/ ATmega1284p 16mhz"

i cant select this board, it is not in the list.

You need to copy the Melzi folder from Marlin to the the hardware folder of the Arduino IDE.

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[www.hydraraptor.blogspot.com]

And what is the melzi folder?

Quote
3Design
And what is the melzi folder?

The melzi folder is the folder that contains the hardware definitions for the melzi. It can be found in the marlin directory.

neildarlow has already explained it above:
[forums.reprap.org]

If you followed my earlier instructions, you will have a folder "My Documents\Arduino\Marlin\Melzi".

Just drag that folder (the Melzi part) to "My Documents\Arduino\hardware" in Windows Explorer.The next time you next start Arduino the Melzi boards should be available.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

My Documents\Arduino\Marlin\Melzi

i don't find the melzi in the marlin map.

Did you download "Marlin-Marlin_v1" from github as a ZIP file and unzip as I instructed above. The Melzi folder will be there if you have done this.

Regards,
Neil Darlow

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I try to write with consideration for all nationalities. Please let me know if something is unclear.
Printing with Mendel90 from fedora 25 using Cura, FreeCAD, MeshLab, OpenSCAD, Skeinforge and Slic3r tools.

I'm no wizard, but I found the following links beneficial. You just have to keep in mind that the videos are GUIDES and not a definitive answer to your particular printer/issues.

[www.youtube.com]
[www.youtube.com]
[www.youtube.com]

Yes, I have a Mendel90. I've found Nophead's documentation and these videos to demonstrate the GENERAL process of calibration helpful. I'm using RAMPS 1.4 so I've had to dig around the internet a little more to get closer to actually printing. I can't help much more than that.

I ve found the melzi folder, i am going to try it again

Edited 1 time(s). Last edit at 01/22/2014 10:40AM by 3Design.