calibration issues? (Page 1 of 2)

it probably doesnt help that the bed is warped left to right, with the high spot being in the middle... pretty obvious when sighting along the front edge... I have tried re-leveling this thing so many times now I can almost do it in my sleep.
any lower and it doesnt stick well, or the fill has gaps and looks terrible

I guess I need to see about getting some glass on there or something... how well does pla work on glass? do I need to use something to get it to stick?

what about mirror? I have seen a few posts where people were using mirrors - I happen to have some 12 x 12 mirror tiles on hand that I can easily cut down (if i can find my glass cutter - lol) they are about 2.5 - 3 mm thick...

I have another question, too - how do I get the print head to go to the home position after a job - and STAY there...
Have tied the G28 x y code, and it will home, then immediately goes to front left corner, slamming there and throwing things out of whack...so right now i kind of have to babysit the darn thing.

thank you AZERATE.

Sorry it took awhile

G28 X0 Y0  ; home X axis and y axis
G1 Z100 F300 ; lower platform to bottom
M104 S0 ; kill extruder temperature
M140 S0 ; kill bed temperature
M84 ; disable motors

The cool thing about this is you can literally copy and paste it into your Slic3r Custom G-Code settings (under printer settings) and delete or modify the lines that are not working for you.
G28 X0 Y0 command as given will home X/Y. So if that is all you want to add, then delete the line causing problems in your end code and paste the line.

Let us know how this works out!

Yes, if I click the home buttons - either all home, or the individual axis buttons, they will "home" properly.

It is only if I try to add the end G code in slic3r that it does this odd, "home" then left front thing...
The RH version I am using is 1.0.6 if that matters any - slic3r had some ending Gcode already in it when I installed - that is how I learned about this in the first place...

it had something along the lines of
     G28 X0 Y0 ; home x axis and y axis
     M84 ; diasable motors

And I have tried it both with and without the "0"s after the axis designations (found the reprap wiki on G code) - no difference either way - it homes, then immediately goes left front.

Ended up just deleting the code entirely after it did this a few times, screwing up the Y alignment pretty badly. Kind of afraid of that code anymore! LOL

And AZERATE - no worries, I understand. thanks for sharing the code.

just out of curiosity, on the G1 line - I get the Z100 part, but what does F300 stand for?

F300 means feedrate of 300 mm/min, it's the speed of the motor. 300 mm/min = 5 mm/s

ok, getting back to the original issue...

the 20mm x 20mm cube is not quite measuring up quite right in the X/Y - i get:
     X = 20.167mm x Y = 19.481mm
I am kind of thinking that the one line that "looks" off is actually where it is supposed to be, and the rest of it is off? is this possible?

Havent gotten a full cube yet to get a Z measurement - came close yesterday but the bridging was terrible so I killed it - gonna have to slow it down or something - sagged something awful! LOL what I did get done (minus one layer) on it measured out to 19.862, so it is pretty darn close on the Z axis...

Oh, and at the moment, I am using an old dial type inch caliper and converting the inches to mms, as it is all I have on hand (digital is on its way)

except i dont think it is a "head dragging" issue - the height has been calibrated to the highest part of the bed...

Other half had to work today, so is going to pick up a glass cutter on the way home this afternoon - I should then be able to get a piece of mirror cut to have a nice flat surface to work with, and we will try again...

on a semi-related note - i do get the "odd" circle issue (flat spots) on the Y axis, suggesting belts are not tight enough, but if I tighten the short belt anymore it causes the rod to bend... and FWIW, this particular SD4 does NOT have the support bushing in mid case (between the pulleys and Z axis stop screw), altho the mounting holes are present... maybe it had it, but the previous owner removed it? or maybe it was never installed? who knows....

would it help if I had something there?

In fact they make no difference. The only difference is you will experience binding sooner if you tighten down the motor too much.

Bearings are better.

Ok, so digging into this thing a little deeper, I have been reading about checking and adjusting the voltage trimpots for the motors...dug out the trusty old NRI multimeter and began checking things out...

Solidoodle states that X, Y & Z should be at 1v ea, and E should be at 0.250v...
My initial readings of what they were as is are below...

X = 1.219
Y = 1.249
Z = 1.210
E = 0.834 (!) no wonder i was getting diagonal pulsing!

so after much fiddling about, power up, test, note readings, power down, unplug, adjust, plug back in, and repeat (don't have a ceramic screwdriver - yet), I now have:

X = 1.003
Y = 1.006
Z = 0.993 (was super touchy - or would it be better to have it slightly over - around 1.05 +/-?)
E = 0.251

test cube coming up...

the first layer gets squished so it tends to be larger than the rest and create a lip. a lip is better than poor adhesion, but if you want you can mess with the z stop to get rid of it. tiny adjustments.