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Keeping the magnetic sheet DOWN?  

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ga
 ga
(@ga)
Estimable Member
Keeping the magnetic sheet DOWN?

So I finally got some nylon to stick, but it's a big print that covers most of the sheet.  When it gets about 15mm high it pulls the magnetic sheet up off the bed.

Anyone have a fix for this?  I thought about clamping but I don't think I can clamp all four corners and still print.  The back left with the power connector would be difficult.

Posted : 12/04/2024 4:21 am
Brian
(@brian-12)
Estimable Member
RE: Keeping the magnetic sheet DOWN?

Print in a enclosure is about all you can do.  Minimizing infill and designing a uniform wall thicknesses on your part can help as well to equalize cooling and combat warping.

But the biggest thing you can do is print in an enclosure. I'd get as close to 45°C as you can get. I'd caution  going higher then that with all of the plastic parts on the printer.

In an industrial printer where everything is metal you'd be printing it with a chamber temperature of 55°C + depending on the type of nylon.

Posted : 12/04/2024 4:33 am
Thejiral
(@thejiral)
Noble Member
RE:

Printing in an enclosure is a must, the hotter the better, MK3 and Mk4 are limited in how warm it can get, unless you reprint the printer in ABS or better and get all the electronics out of the enclosure. Still, even a stock Prusa Enclosure is much better than none. 

Forget about printing build plate edge to edge object with regular Nylon. 

You might have a chance with CF Nylon, maybe. That warps a lot less than regular Nylon. 

This post was modified 1 month ago by Thejiral

Mk3s MMU2s, Voron 0.1, Voron 2.4

Posted : 12/04/2024 9:20 am
fuchsr
(@fuchsr)
Famed Member
RE: Keeping the magnetic sheet DOWN?

I routinely print one model that also lifts off the sheet (albeit not nylon). I use small paper clips. You do need to experiment where to put them but I have been able to get two in the front and two in the back. Yes, the power connector gets in the way but I was able to finagle it close to it. I also use Layerneer to keep the model to the sheet.

Posted : 12/04/2024 12:06 pm
ga
 ga
(@ga)
Estimable Member
Topic starter answered:
RE: Keeping the magnetic sheet DOWN?

Thanks all for the advice.  I've been using a half enclosure (front only), but will try kludging up something for the back.  I also printed some small clips to hold the sheet to the print bed, but haven't had a chance to try them yet due to some seemingly random crashes I need to resolve when printing PETG (RYNO).  Hopefully will get back to this soon-ish.

Posted : 15/04/2024 5:57 pm
Zappes
(@zappes)
Reputable Member
RE:

Considering the rather high bed temperature you need for Nylon, I very much doubt that printed clips will survive.

My models on Printables
Posted : 16/04/2024 7:34 am
ga
 ga
(@ga)
Estimable Member
Topic starter answered:
RE: Keeping the magnetic sheet DOWN?
Posted by: @zappes

Considering the rather high bed temperature you need for Nylon, I very much doubt that printed clips will survive.

Thanks, I am concerned about that, but mostly from breaking based on the thin body needed to clear the printhead in some places.  But you're right, that may be a problem.  The plastic I used for the clips (Matterhackers RYNO) has a glass transition temp of 80, and the glass transition temp for the nylon I'm using (Taulman 645) is 52, so maybe it won't be a problem.  I've been using a bed temp of 55 (recommended is 30 - 65).

Posted : 16/04/2024 5:00 pm
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