Solved Z axis height is off

Hello Everyone,

Recently received a Robo 3d R1 (last week) and after printing a larger item I am noticing that the Z height of the print is off by a few mm. The part in 123d shows 50.6 mm, measuring the part I'm seeing 46.0375.
Please see the picture for reference, the top flat portion of the model is quite a bit longer than the main head portion (it was printed flat on the print bed at the same time the head was printed).

I have an idea of what the issue might be, when moving on the Z axis the block holding the nut rotates a few mm in each direction on both Z threaded rods, if this is in fact the issue is there a simple fix? I will attempt to take a picture or video of what I think the issue is when I get home tonight.

Thank you in advance for any assistance with this.
Drew

 

I forgot to include that this is printed using Colorfabb PLA/PHA print at 200 degrees with 25% infill, please let me know if additional information is needed.

 

Try printing a 10mm calibration cube and seeing what height it comes out at.

There's a couple usual suspects to height like this:

First: Z Steps per mm is off

In mattercontrol find the EEProm settings. Verify the Z steps per mm is 2560 and not 2267.etc. This 10% error sounds like the most likely culprit to your issue.


Second: Torque stall

This is usually caused by no lubrication on the Z threaded rods. It can stall while trying to raise up the axis causing incorrect values. Lubricating your rods with white lithium grease is a good option


Third: Loose helical couple to threaded rod

The Z axis threaded rod connects to the motor with a aluminum spring looking device called a helical coupler. If you are able to grip the helical coupler and twist the threaded rod you'll need to retighten it down. Add some teflon tape to the bottom if you can't get it tight enough to grip.

 

Hello Mike,

Thank you for the quick response, it's very much appreciated.

I'm able to remote in to my home computer and found that the Z steps was in fact set to 2267, I will change this to 2560 per your recommendation, print a calibration cube (measure it) and check your other recommended items tonight.



Drew

 

Hello Mike,

I have set the Z steps to 2650, print a 10mm cube and measured 9.34mm on Z. After double checking the EEPROM settings I found that all of the values show 0 so I restarted MatterControl and found that it went back to 2267, trying this a few times with restarting the software after saving EEPROM made no difference. I'm going to restart my computer and power cycle the Robo 3d and try again.

Drew

 

Flash the 8mm firmware: http://help.robo3dprinter.com/Wiki/RoBo_3D_Firmware

 

Do I flash the Auto_Level_7_17_8mm.ino or Marlin.ino?

 

auto_level file. The marlin.ino is just a remnant and would error if you tried opening.

 

Thank you, flashing now.

 

Flashed and the EEPROM settings are showing the correct value, printing another calibration cube now.
Thank you for your help.

 

Hello Mike,

The cube is now coming out properly, I appreciate your help.

Thank you,
Drew

 

I have the exact same problem with a new Robo3D I received last week. Was loosing about 1mm per 10mm in height. I was able to change my z value using an attached lcd screen. Thank you much for the help Mike.

 

Having the same problem with a Robo 3D R1.
I printed a 25mm cube, and the height measure 23mm, I used CURA.

Is there a way to change the steps per mm in CURA?
Thanks!

 

Nope.

The change needs to be made in the firmware configuration.h file. http://help.robo3dprinter.com/Wiki/RoBo_3D_Firmware

 

We need a sticky on this. First thing people should do upon unboxing is updating the firmware. It seems that almost all of the new ones are shipping with the wrong firmware.

 

I flashed it.
But I opened the configuration.h file and cant seem to find the value of the steps, I checked in the the configuration advanced also.
I changed the values in matter control, and clicked on Save to EEPROM. Does that changes in the printer itself or just in the program?

 

Just flash the 8mm auto level firmware. It already has the correct esteps in it. No need to change anything within the firmware.

 

Perfect!
Well, I just printed the 25mm cube again, and now the height is 26mm (before was 23mm). X and Y are okay, both 25mm.
Should I make some adjustments?

 

I received the R1 last week and also had to flash the firmware to get the Z mm steps value to be correct. I'm familiar with building computers and know that downloading the latest drivers for a device is always a good idea, guess I never thought about the fact that the latest firmware should be flashed right away. I agree that it would be a good idea to somehow sticky such information. Especially including how to determine which model R1 you have and its corresponding firmware.