Unresolved Issues with Z Step calibration when using auto level

Hello All,

I have a Robo3D r1 with the auto level and I am currently stumped on an issue. Here are my specs currently.

Filament type: PLA - generic non named from fry's
Extruding Temp: 210c
Bed Temp: 50c
Bed makeup: Glass with watered down wood glue for platform adhesion.
Firmware Version Auto Level 7.17 5/16in rod
Hotend E3DV6
RepRap XXL LCD screen to print from sd card.

When I first started using the printer I noticed that the calibration for the number of steps per mm was off for the z axis and my prints were coming out smushed. I recalibrated it with the following settings.

#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,2582.6,723.38}

Now the issue that I'm having is when I do a print with the auto calibration on using the following start code in Cura I get a print with massive ridged spots and the overall height is off. Here is my start code that I am currently using.

Code:

G21        ;metric values
G90        ;absolute positioning
M82        ;set extruder to absolute mode
M107       ;start with the fan off
G28 X0 Y0  ;move X/Y to min endstops
G28 Z0     ;move Z to min endstops
G29             ;autolevel bed
G1 Z15.0 F{travel_speed} ;move the platform down 15mm
G92 E0                  ;zero the extruded length
G1 F200 E3              ;extrude 3mm of feed stock
G92 E0                  ;zero the extruded length again
G1 F{travel_speed}
;Put printing message on LCD screen
M117 Printing...

Here are two different prints showing the difference side by side. In image1 the left is the one that had the auto level on, right is the one with it off. Image 2 shows the ridges on the print compaired to that of image 3. Both of these were printed from the same exact stl file and I can upload that if needed also. I'm trying to figure out why when the auto level is on the z calibration seems to be off or the printer is missing steps when raising the print head. Any suggestions would be greatly appreciated.

 

Hey Ziggy,

Thanks for the reply. I purchased my printer back in August and I even measured the threaded rods and they were 5/16ths but I can try the 8 mm firmware. The step calibration that I'm using is from printing a 175mm tall object and measuring what the printed height/model height was and adjusting the steps accordingly. When I first got my printer they only had one version of the firmware for the auto level so I don't know if that makes a difference.


As for the auto level. I'm not using matter control at all. I slice the model with Cura and then print from the SD card with the LCD screen. The difference in the two prints is weather or not I had the G29 code in there or not. I tried looking through the firmware to see if there was a second place for the step calibration that would be used for the auto level prints but I wasn't able to find anything.

 

And I realized that 5/16th and 8mm are the same diamater but different threads. I'll try the other firmware when I get home and see if that fixes the auto level but if the steps per mm are the only difference between the two then I don't think it will make a diifference.

 

Okay, I updated to the 7.17 8mm firmware and Here are the results. Printing with the following start code I get a good print. No issues with it squishing but it is harder to get the z offset set properly and I have to do it manually on each print.

Code:

;M190 S50 ;Uncomment to add your own bed temperature line
;M109 S210 ;Uncomment to add your own temperature line
G21        ;metric values
G90        ;absolute positioning
M82        ;set extruder to absolute mode
M107       ;start with the fan off
G28 X0 Y0  ;move X/Y to min endstops
G28 Z0     ;move Z to min endstops
G1 2.0
G92 Z0
G1 Z15.0 F4800 ;move the platform down 15mm
G92 E0                  ;zero the extruded length
G1 F200 E3              ;extrude 3mm of feed stock
G92 E0                  ;zero the extruded length again
G1 F4800
;Put printing message on LCD screen
M117 Printing...

When I print with the auto level on, the print is now too tall and the last layer was stringy and the individual traces can be moved with your fingers. I couldn't get a good picture for the difference but it is about 10% taller than it should be. Here is the start code I'm using for this one.

Code:

;M190 S50 ;Uncomment to add your own bed temperature line
;M109 S210 ;Uncomment to add your own temperature line
G21        ;metric values
G90        ;absolute positioning
M82        ;set extruder to absolute mode
M107       ;start with the fan off
G28 X0 Y0  ;move X/Y to min endstops
G28 Z0     ;move Z to min endstops
M565 Z-1.0 ;z offset
G29             ;autolevel bed
G1 Z15.0 F4800 ;move the platform down 15mm
G92 E0                  ;zero the extruded length
G1 F200 E3              ;extrude 3mm of feed stock
G92 E0                  ;zero the extruded length again
G1 F4800
;Put printing message on LCD screen
M117 Printing...

This gets me a great initial layer but the subsequent layers are too tall and it doesn't print properly. Any ideas on what I can do to try to fix this?

 

So I've tried both firmware versions. If I leave the z step calibration alone on the 5/16ths one the print is smushed. If I adjust it to the correct steps it will only smush it when I use the G29 code and print just fine with that line omitted. If I use the 8mm firmware. The print with no adjustments to anything and the G29 line omitted the print comes out properly but if I add that code back in it comes out too tall. What about the G29 line is changing the z step calibration/how tall the final product comes out?

 

The firmware I'm getting is directly from robo's site. The links are from http://help.robo3dprinter.com/Wiki/RoBo_3D_Firmware

As for the log file. How would I go about getting this. I'm printing directly from the sd card reader on the reprap xxl lcd screen. I'm using cura to slice and put the g-code directly on the card.

 

I sent you a pm with the log file and the gcode from the sd card. Making the changes to the g28 line now has it auto home to the center of the bed after all the endstops. I've never gotten mattercontrol to work for me properly and after doing a z calibration on it in the software it had issues with going to -37z durring the zero and then printing 12mm above the bed. Cura has worked the best for me so far and I'm currently using 14.07 version. I have to go to be myself but will post in the morning with the results of the latest test print.

 

The print I did last night also had problems with the z height being too tall on each layer so the layers didn't bond properly and it left the top almost all strings. I was watching it for a bit and it almost seems like when the autolevel compensation as the print head moves side to side the z axis is missing steps on the downward movement. I don't know if there is a way to tell for sure or if there is a way to try to fix that.

 

Z height too tall probably means you're running the wrong firmware.

Measure out an inch of threads and count how many there are. Or measure the thread pitch with a micrometer.

if it's 18 or 1.411mm then it's 5/16, if it's more than 18 or 1.25mm then it's M8

 

I've got the right firmware. The prints come out correct height wise when I don't use the auto level. The only difference between the two different prints code wise is if its got the g29 line in it or not. With out it the print does fine after manually adjusting for the bed height. With it, the print comes out too tall on the 8mm firmware and too short on the 5/16ths firmware.

Here are the scenarios that I've done prints/tests with so far.

1. 5/16ths firmware, z step calibration changes as noted above, no auto level. Print comes out fine.
2. 5/16ths firmware, z step calibration changes as noted above, with auto level. Print comes out too short and multiple layers are smushed out the side of the print.
3. 8mm firmware, no z step calibration changes, no auto level, print comes out fine.
4. 8mm firmware, no z step calibration changes, with auto level, print comes out too tall.

So based on that evidence the 8mm firmware is the correct firmware for my printer but I will grab my reloading calipers from my parents house later and measure out the threads just to confirm.

My main question right now is what is it about the auto level that is causing the z layer heights to be different and not correct for the settings that I have on the printer.

 

what autolevel are yu running? The APL from MC?

 

I'm using the 9 point autolevel that is triggered by adding the G29 line to the start code on the print. I don't use MatterControl as I've never been able to get it to work properly and doesn't have the level of control that Cura does.

 

Try printing the 5mm calibration steps and be sure feed and flow rate are at 100%

http://www.thingiverse.com/thing:24238

 

I will try that when I get home. Do you want me to do a specific infill setting or leave it at 20%?