Ready to throw this thing out

I was able to get something to print last night.


I had much better luck printing with Simplify3D, using PLA that came with the printer bed at 55c and 200c for filament.

Had to use a Z+.5mm offset to get a good first layer.

Other items changed

Upgraded to E3D v6 hot end
Upgraded to M8 rods and nuts
Upgraded to latest firmware (Auto_Level_6_10)

Upgraded firmware for the E3D thermister
//#define TEMP_SENSOR_0 1 //robo, old setting
//Change for E3D hotend Semitec thermistor
#define TEMP_SENSOR_0 5

//#define HEATER_0_MAXTEMP 240 //robo, old setting
//Changed for E3D hotend
#define HEATER_0_MAXTEMP 310

Upgraded the firmware for the M8 Rods
#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,2560,723.38}

Also found I had to add a little white lithium grease to the threaded rods to prevent them from "binding", this helped a lot and was able to run them all the way up and down with no "binding"

I was able to tighten the belts, the bed has an easy adjustable belt tightener, remove the screw, slide the belt off, move it 1-2 teeth and put it back in the belt holder, put the screw back in.

This is also true with the other belt, mark the belt, cut the 2 zip ties move it over 1-2 teeth, replace the zip ties. no need to cut the belt and do the above pictured modification.

I will continue to work on getting a better understanding of what is going on and write something up.

 

Z axis is still not moving up the correct amount, i'm getting correct x and y now but on something that should be 50mm high I only get 45mm, how / where can I fix this?

 

That 45mm/50mm is suspiciously close to the 1.24/1.411 ratio between the M8 and 5/16 rod thread pitches. Are you sure those step_per_unit values got downloaded? Maybe a filename mixup in the edited configruration.h?

 

//#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,2267.72,723.38} // default steps per unit for RoBo 3D R1
#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,2560,723.38} // M8 Rods
#define DEFAULT_MAX_FEEDRATE {500, 500, 5, 25} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {9000,9000,100,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot.

This is what is in my configuration.h file.

 

I got that. It's what you showed above. The measurement is suspiciously close to having the old step value. Are you sure it downloaded properly? Did you use the Arduino application to download it? You can do a test with a really large or small value to make sure you are downloaded what you think you changed. OK?

 

Not sure I understand that, yes I use the Arduino utility to recompile and upload to the configuration to the card. I have done this for the upgraded E3d v5 and v6 hot end and also for the reprap discount lcd diaplay and they both uploaded as both are working. I checked all my config files (I keep everything in version control) and since the M8 upgrade all my configuration.h files have the new values. Is it possible to download from the arduino card to see what is on it? or get it to spit out a line of config?

Thanks.

 

Ok, to rephrase my suggestion - as a sanity check on your config file edit and download just change the Z steps per value to something very noticeable like 1000. Then download and manually move the Z axis say +10mm and it should move over twice that.

Do you agree that the 45/50 ratio is suspicious? It could be something else but it's worth double checking.

 

Ah, ok, I will give that a try, I'm doing a test print at the moment, I put this in my start code M92 Z2560 to see if it would help.

 

I confirmed on the LCD and it is 2560. I printed a 50x50x50 cube, X and Y are 50mm by Z is only 36mm high, I have to set my extrusion to 80% otherwise way too much material is extruded (as i gather it's not moving up the correct amount).

 

I just did some measurements on 2 other test pieces that I made and different sections show different percentages of incorrect height.

The 50x50x50 cube is 72% the height it should be
another piece has 2 steps on it

Its 50mm total height
Should be - Actually - %
50 mm - 45mm (90%)
30mm - 25.2 (84%)
20mm - 20mm (100%)

Second model same item at 50% size
Should be - Actually - %
25mm - 20mm - 80%
15mm - 12.23 - 82%
10 mm - 7.25 - 72.5%

What am I missing?

I'm printing directly from SD cards now, using Simplify3D, it has been printing better X and Y but this height issues is still a major problem (I though it was an issue printing from the USB and it seemed to be worse printing directly from the PC).

 

I also measured my 8mm rods and 5/16th rods to make sure there wasn't a mistake. But they look good and wouldn't account for this much of an issue.


Here are the pictures of the shapes printed.

 

I now suspect your the problem is that some sort of poltergeist or ghost has invaded your machine.

Did you try measuring the length of manual Z movements? Lower the nozzle to the bed and manually move say 45mm and use your 45mm cube to gauge the actual movement. If you get a shortfall then try this a number of times to look for consistency. If it is inconsistent then the z steppers are skipping due to friction and an insufficient driver power. There are posts with references to adjusting the stepper driver power level. If the shortfall is consistent then I think you have a ghost.

 

Can you provide a bit more information on "you can tweak that", what does it adjust, current/voltage? is there a danger in this?

It actually moves up and down the Z axis very smoothly, I removed the 5/16" rods and installed the M8, one of the 5/16" was bent and wiggled back and forth. I added some grease to the rods to get them to move as smoothly as possible.

I will measure how far it's actually going and check all the connections to the controller.

 

Ok, I have done all this, I manually checked the height, had it move 10mm and remeasured, did this several times at different heights and it was bang on. I created some G code that moved it up and down many many times (including some x+y) to try to tax the stepper driver to see if it would overheat and it just kept on going and going and as I kept having it go to 0 i could see it was in the right location. I tried to hold the rods from turning and it took more effort that expected to get it to jump a step.

I took the bottom off and turned up the power just a little (there was also some heat compound from the heat sink that was on the circuit board, I cleaned that off), I checked all the wires and connectors and everything look good and is seated (i unplugged the wires to make sure all the molex connectors were seated in the connector).

I printed another cube 25 x 25 x 25mm and it came out 25 x 25 x 21.6mm

I'm going to try printing from my PC but I'm really at a loss.

Is there anything that the SW / Slicer could be doing?? I'm using Simplify3d could it be missing the z+ steps??? Is there a way to see this?

Thanks.

 

Yup looks correct

; layer 122, Z = 24.99
G0 X110.799 Y88.918 F4800
G0 Z25.49 F1000
G1 E0 F1800

I decided to swap the stepper driver for the X and Z axis to see if that makes any difference.

If that doesn't work I'm out of ideas, I guess I could plant a flower in it...

 

Swapping the stepper driver has done something good. I now get 24.49mm high, but it looks amazing and I'm sure I can change a setting the get the .5mm back (I believe the first layer is a %)

Right is after stepper driver was swapped it was printer from SD, middle was printing from PC via USB before stepper driver swap and Left was printing from SD also before stepper driver was swapped.



Hopefully I can call this fixed. X and Y look very good and now Z looks good.

Time to print a few more test items.

Thanks for all the input!