Ontopic The 3D printing thread

Is that a dual motor Z rod setup, or two Z rods with a belt drive at the top holding them together?
Two motors, two drivers, and Z axis auto align which is a Marlin 2.x feature.

Homes with the inductive probe in the center, then probes the left/right sides of the bed and turns one of the steppers to auto tram the X carriage.

Previously I'd do it by calling G29 V4 from a terminal, looking at what Marlin spits out and rotating one motor by hand. This makes it easy.
 
You should do that actually. Use G29 V4 to make the printer spit out a map of the bed, then use that to level the build plate. One full turn of a M3 screw = 0.5mm up/down. Repeat a few times and it'll be flat.
 
Got the bed levelled to +/- 0.03 according to the probe.

When I send the Z to 0 (G1 Z 0), should it remove all clearance between the nozzle and the bed?
 
Nice. 0.03 is beautiful, and the printer will correct that out.

Z=0 should be zero nozzle/bed gap. I set the Z to 0.1 (G21 Z0.1) and slide a 0.1mm thickness gauge under the nozzle.
 
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From 3D printing land here:

- got the bed properly mounted on my printer with all 6 mounting holes and not hitting the stepper. And got a fresh sheet of thick McMaster-Carr PEI on one side of the spring steel sheet, and kapton tape on the opposite side for PETG. I need to do up the bed wiring harness a bit better, but after that she'll be good to go.

- Brought my brother a Maker Select Mini V2 and spool of green filament for christmas.
 
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Nice. 0.03 is beautiful, and the printer will correct that out.

Z=0 should be zero nozzle/bed gap. I set the Z to 0.1 (G21 Z0.1) and slide a 0.1mm thickness gauge under the nozzle.
I was doing almost that exact thing. I sent it to 0, then used my feeler gauges to figure out how much I needed to adjust the Z probe offset. I was about 0.2mm off.
 
Remembered too late that I shouldn't print PETG on my real buildtac bed, and ripped the fuck out of it. I was making some spare BLTouch mounts in case the existing one gets broken somehow (don't want to go through the trouble of reflashing to stock marlin and reinstalling the Z end stop just to reprint the broken mount).

It worked fine on the fake buildtac bed that came with the printer, but once that wore out, the PETG started adhering so hard that it would leave outlines permanently in the sticker.

Always blue tape in the future. doh!
 
Lay down some glue stick on your print bed before you print PETG on it. Or put down some painters tape. Otherwise, yeah... I destroyed my previous PEI sheet that way.

First print on the "now properly mounted, now with a proper PEI sheet" heatbed:

18121929Resized20181219080851.jpg
 
The PEI sheet I use is McMaster-Carr 7576K13. Comes in a 1' x 2' rectangle, enough to do two print beds. I glue it down with 3M 468MP.
 
Oy vey, the heated bed seems to be haywire. The bed heats up and just stays at 110°C without being commanded.

What do I do?

Shorted heatbed MOSFET?

Power down the printer, disconnect the heat bed wiring from the control board. Grab a DMM, do a diode test from heatbed negative to ground. You should get open circuit (or 2V or whatever depending on how the circuit works) in one direction, 0.5-0.7V diode drop in the other direction. If you get 0.0V both ways, that's your problem... and your choice is either changing out the board, or replacing the MOSFET.

I can't find a picture of the board which doesn't have the heatsink on top of those MOSFETs (which does jack shit, as those packages are cooled through their thermal tab, not their face...) but I'm guessing they're in a TO-252/DPAK package. You can snip the leads, put a big blob of solder on the tab and get them loose without too much trouble. Then you can properly solder or even ghetto rig another one on.
 
If it makes you feel any better, I just lost a 3 hour print to my heatbed temperature connector coming loose and causing a MINTEMP error...
 
Shorted heatbed MOSFET?

Power down the printer, disconnect the heat bed wiring from the control board. Grab a DMM, do a diode test from heatbed negative to ground. You should get open circuit (or 2V or whatever depending on how the circuit works) in one direction, 0.5-0.7V diode drop in the other direction. If you get 0.0V both ways, that's your problem... and your choice is either changing out the board, or replacing the MOSFET.

I can't find a picture of the board which doesn't have the heatsink on top of those MOSFETs (which does jack shit, as those packages are cooled through their thermal tab, not their face...) but I'm guessing they're in a TO-252/DPAK package. You can snip the leads, put a big blob of solder on the tab and get them loose without too much trouble. Then you can properly solder or even ghetto rig another one on.

Yeah, it's shorted both ways.

How do I get the heatsink off of it? It looks like it's got some sort of white thermal paste between the sink and the MOSFET.
 
It looks like the shit job they did of mounting the board let the big solder pad on the backside of the board run to ground. :/

I can probably go to the local supply store and pick up a MOSFET, I just need to know which one to buy.
 
Try just twisting it off... it's probably just silicone, it should give way before anything else breaks.

Take a pic. I'll go looking up some part #s. What sort of electronics stores do you have in your area?
 
Try just twisting it off... it's probably just silicone, it should give way before anything else breaks.

Take a pic. I'll go looking up some part #s. What sort of electronics stores do you have in your area?
I will take a picture in the morning. I have a pretty good one called, "electronic parts", where I will start looking.