Calibrating, hitting the bed

[m4r1n5]

By the July 14, 2013 manual, Im on pge 151 and im hitting the bed on the LAST code "G0 Z5 X-77.94 Y-45 F3500". the other 2 codes gave me roughly 5mm distance, but this one hit the bed and put pressure before I shut it off. what do I do to correct it?

[foshon]

I would give the home screw on the tower the effector is travelling to 3 turns in. Try it again, if it hits add a few more turns.

[cambo3d]

better way to do this.. to absolutely avoid hitting the bed is...

manually move it to about 5-10mm off the surface of the bed. Then slowly move downward. once you get close.

use m114 command, to display current position. (or was it m119,, if forget which one)

that' will tell you how far your z height needs to be adjusted.

once you have that adjusted. use the above gcode and continue what you were doing.

[JohnStack]

That's a great suggestion!

[m4r1n5]

My Z axis is too high. I screwed in the stop screws to all be uniformed length, went through the initial setup again and am now on pge 156. I have "G0 Z5 X0 Y90 F3500" but when I went down to "0.00" im still bout 3mm too high and of course it wont drop any lower. If I were to change the EEPROMs X,Y,Z settings to have different lengths, i.e " X max length 364.07, Y max length 368.50....", would that be ok? or do they all have to be the same and Ill have to keep messing with the screws.

[kbob]

You can also lower the head in increments of 0.01 mm from the printer's front panel. Main menu -> Position -> Z Position, then twist the knob. You can read the Z position on the LCD display.

[m4r1n5]

So I've been messing with the X axis screw stop to adjust the length, BUT i still have about 2.9 mm to go and I'm looking like this...

[img]http://i1326.photobucket.com/albums/u65 ... 7a1536.jpg[/img]

ANYONE have a solution to this???? The other 2 stopscrews look like this....

[img]http://i1326.photobucket.com/albums/u65 ... 5383db.jpg[/img]

[Polygonhell]

I would say you have a mechanical issue, at the top the 3 carriages should be even when homed.
All the screws are for is to dial that in.

Think about it this way when all three travel downwards by the Z height the Hotend should be on the bed in the center.

Or possibly you have the Steps/mm mismatched between the firmware and the EEPROM.
What firmware, and what changes did you make and what vales are in the EEPROM for the steps/mm

[m4r1n5]

my lcd shows repeteir 0.80. I put it back to home (G28) AFTER i adjusted the X axis to have the same stopscrew length as the others. all 3 measured pretty much the same so it might be firmware. i'm going to start over and see where this gets me.

[m4r1n5]

SO....I started the software calibration over again. I still came up with my X axis stopscrew being farther in than the other 2, but not as bad as my last pic and its now calibrated. I ran all 4 scripts and the only one i have left is the center being about .1-.2 mm too high. how do I adjust that?

[lordbinky]

This is what took me the longest to get right, and here is how I was doing it at the end.

I took thin cardboard (like a cereal box, I specifically used the box my trash bags come in) and made it into strips which I could stack and had enough length to move them around under the hot end.

I set my max to be about 5 mm above the bed. Brought everything to temp. and began calibrating the printer_radius.

Based on the manual, Script 1-3 (the ones for each off center measurement) I would check their height using the cardboard slices.
So,
1) Adjust the screws so that script 1-3 places the nozzle the same number of cardboard slices.
2) Next, you check Script 4 (the center) and see if it is lower or higher than the perimeter heights (which are all the same now... right?)
3) Adjust your printer_radius in the firmware accordingly.
4) Return to step 1.

I recorded each iteration in a google document spreadsheet because I was impatient and couldn't handle .5 increments, and figured a binary search would home me into the value the fastest.
That is, if I was convex the first time, I made a large change to printer_radius such that the center to perimeter was concave. Then I make my printer radius the median (middle) value and do the first two steps again. Then I keep taking the mean between the newest concave and convex values until printer radius results in equal center and perimeter heights.

Once your movement is flat across the printing surface, I lower my max height back down to the bed and do any minor tweaking with the paper test.

edit: To add a couple helpful tidbits in this post, make sure you turn your EEPROM off in firmware while performing the PRINTER_RADIUS adjustments , #define EEPROM_MODE 0 . BEFORE you do that, take any changes to the eeprom values you have made and put them into the firmware. Just use the find function and make sure everything matches, you can also put in a // before the old value which will hide it as a comment so you know what it was originally in case you feel to need to take a step back at any point. After getting PRINTER_RADIUS where you want it, don't forget to turn the eeprom back on by changing the setting back to 1 or higher. You don't absolutely have to turn it back on if you don't want to though.

[m4r1n5]

Not familiar with "configuration.h" or Arduino in general. i found the file in the "Repetier" application, changed the "PRINTER_RADIUS" to a larger number, uploaded it but the hot end still stays the same height. what am I doing wrong?