Zebra Plate

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Jules
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Re: Zebra Plate

Post by Jules » Tue Sep 29, 2015 5:48 pm

Tim wrote:One thing I just found out about the Zebra plate: as far as the inductive z-probe sensor can detect, the two sides of the zebra plate are not symmetric. I had the sensor mounted perfectly for detecting the surface of the white side, keeping the nozzle about a mm or more above the surface (note that the inductive sensor is really detecting the copper layer under the surface, not the actual surface). I flipped it over to the black side, ran the Z-probe calibration, and it rammed the nozzle into the plate before the Z-probe triggered. So the sensor thinks there's at least 1 mm depth difference to the copper layer on the black side vs. the white side, although visual inspection would suggest that they are the same. Possibly the black and white sides have different dielectric properties. At any rate, I had room to spare to lower the sensor a small amount, so it should work on both sides now. It was a bit of surprise, though.

I'm still trying to figure out exactly how to properly set the overall height, which is quasi-independent of the probing the way I have it set up, but it's neat to no longer have to worry about whether the plate is bowed, or bent, or tilted. The probe captures it exactly and the Z-stepper keeps the bed exactly positioned under the nozzle.
That makes sense - the copper layers on my plates look a little bit different, depth wise. (but not by much) I'm glad to know auto-leveling can work with the Zebra. Where did you wind up attaching the leveling sensor Tim? (You've got a homemade version because of the dual and the different board, right?)

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Tim
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Re: Zebra Plate

Post by Tim » Tue Sep 29, 2015 7:52 pm

Jules wrote:Where did you wind up attaching the leveling sensor Tim? (You've got a homemade version because of the dual and the different board, right?)
I made a couple of posts on another thread, with a topic name specific to either the dual extruder, the Smoothieboard, or both, which probably means it wasn't read by most people with a more standard setup. But anyway, to summarize, I remodeled the dual extruder fan duct with a hole right through the middle of it, and mounted the sensor in the hole. It took a couple of design iterations, but I managed to do it without much redesign of the fan duct other than to push the fan out about 4mm or so. It puts the sensor between the two extruders and a couple of cm in front.

The issue with that arrangement is that when you home the extruder in X and Y, it puts the sensor off of the front of the bed plate, where there isn't any metal to sense. For that reason, I can't get rid of the Z-min endstop switch, but must figure out how to make the endstop switch and the probe coexsist in peace.

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Jules
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Re: Zebra Plate

Post by Jules » Tue Sep 29, 2015 8:12 pm

Tim wrote:
Jules wrote:Where did you wind up attaching the leveling sensor Tim? (You've got a homemade version because of the dual and the different board, right?)
I made a couple of posts on another thread, with a topic name specific to either the dual extruder, the Smoothieboard, or both, which probably means it wasn't read by most people with a more standard setup. But anyway, to summarize, I remodeled the dual extruder fan duct with a hole right through the middle of it, and mounted the sensor in the hole. It took a couple of design iterations, but I managed to do it without much redesign of the fan duct other than to push the fan out about 4mm or so. It puts the sensor between the two extruders and a couple of cm in front.

The issue with that arrangement is that when you home the extruder in X and Y, it puts the sensor off of the front of the bed plate, where there isn't any metal to sense. For that reason, I can't get rid of the Z-min endstop switch, but must figure out how to make the endstop switch and the probe coexsist in peace.
Apologies! ;) i see that you did post pictures and specific instructions in the one over on the Dual Extruder board. (Think i got interrupted in the process of reading through that one yesterday.)

minusbacon
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Re: Zebra Plate

Post by minusbacon » Wed Sep 30, 2015 2:33 am

I have to reset my z-stop and bed level. What nozzle and bed temp do you guys use to do this? I was thinking PETG temps like 250/80. Too high?

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Jules
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Re: Zebra Plate

Post by Jules » Wed Sep 30, 2015 2:46 am

minusbacon wrote:I have to reset my z-stop and bed level. What nozzle and bed temp do you guys use to do this? I was thinking PETG temps like 250/80. Too high?
Set it for the temps for whatever filament you will be mostly printing. (And keep in mind, that each different roll of filament will need to have the Z-Offsets recalculated. Don't be surprised if they are different depending on whether you are printing on the white surface or the black one.)

Also keep in mind that bed temps are lower for Zebra plates.

minusbacon
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Re: Zebra Plate

Post by minusbacon » Wed Sep 30, 2015 2:54 am

Jules wrote:
minusbacon wrote:I have to reset my z-stop and bed level. What nozzle and bed temp do you guys use to do this? I was thinking PETG temps like 250/80. Too high?
Set it for the temps for whatever filament you will be mostly printing. (And keep in mind, that each different roll of filament will need to have the Z-Offsets recalculated. Don't be surprised if they are different depending on whether you are printing on the white surface or the black one.)

Also keep in mind that bed temps are lower for Zebra plates.
Right. I don't plan on sticking to one type of filament. Going to start experimenting with PETG, ABS, and Ninjaflex eventually. Since PETG/ABS use higher temps I'd rather set the z stop and level the bed at those higher temps rather than PLA temps and accidentally ram the nozzle into the bed when the temps are higher.

Did a search for PETG printing temps and one post said they print PETG at 250/80. *shrug*

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Jules
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Re: Zebra Plate

Post by Jules » Wed Sep 30, 2015 3:04 am

It doesn't really matter which one you pick. As long as you are printing something different, you are going to have to make Z-Offset adjustments, either closer or farther away, depending on where the current filament falls in the temperature range relative to the one you used to set the gap.

So pick the temps for the one you plan to print the most of. Or use 250/80. It doesn't matter.

minusbacon
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Re: Zebra Plate

Post by minusbacon » Wed Sep 30, 2015 3:30 am

Was trying to just use the back clips like with glass but once I started heating the bed it bowed a bunch and lifted off the front of the bed.

Are you guys using small binder clips (like the two that came with the M2) for the front of the Zebra plate too? Small clips fit on the back fine, but the front is extremely tight. Just want to make sure small binder clips are ok in the front because the heating element goes to the edge of the front of the bed. I don't want start using them there and find out I damaged the heating element.

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Jules
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Re: Zebra Plate

Post by Jules » Wed Sep 30, 2015 4:00 am

minusbacon wrote:Was trying to just use the back clips like with glass but once I started heating the bed it bowed a bunch and lifted off the front of the bed.

Are you guys using small binder clips (like the two that came with the M2) for the front of the Zebra plate too? Small clips fit on the back fine, but the front is extremely tight. Just want to make sure small binder clips are ok in the front because the heating element goes to the edge of the front of the bed. I don't want start using them there and find out I damaged the heating element.
Yes, I use them on all four corners. (Mine have been relaxed a bit though. They are snug, but do not dig into the bed.) Two pairs of pliers and some muscle will take care of it. (And if i have enough muscle to take care of it, anybody should. :D )

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Tim
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Re: Zebra Plate

Post by Tim » Wed Sep 30, 2015 4:42 am

minusbacon wrote:Are you guys using small binder clips (like the two that came with the M2) for the front of the Zebra plate too? Small clips fit on the back fine, but the front is extremely tight. Just want to make sure small binder clips are ok in the front because the heating element goes to the edge of the front of the bed. I don't want start using them there and find out I damaged the heating element.
Yes, I use small binder clips. The two in the back and the front right one I have at the corners. The front left one is moved over to where it is positioned more or less over the belt of the Y stepper. That keeps it clear of the dual extruder head when it homes X and Y. The dual extruder is a lot worse about running into things than the single extruder.

And by the way, I have been running my Zebra plate at the same temperature that I ran the glass plate at. I started out with the temperatures they claimed were best with the Zebra plate, but when things didn't stick well, I ratcheted up the temperatures until I got good adhesion, and found myself back at the original temps. Go figure.

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