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Re: Wanted - Taz 6 - removable flexible bed mod?????

Posted: Sat Mar 03, 2018 3:05 pm
by nuroo
These are the magnets I used for my delta. (ended up using 7 instead of 4, just so there was no gaps between build plate and metal sheet, as you can see I was afraid to put any on heater pad itself)

http://appliedmagnets.com/bar-magnets-2 ... p-608.html
They are very strong but more importantly are N42SH grade for high temperature applications. Most regular magnets lose magnetic attraction force with higher temperatures.
20180226_163916 (1).jpg
The hesitation I had was for the magnetic field created by the magnets and metal plates passing thru the AC current of the heater pad when its on. I didnt know if that would cause a problem some how. I have no doubt the magnets are strong enough. If they arent they can be double or triple stacked.

If AC current passing through the magnetic field is no issue then we are on the something:

Taz 6 moving plate : magnets -> silicone heater pad -> rigid plate : flexible plate -> build surface of choice

Modded my Delta with something similar and I love it. One hand print removals, no tool marks on print or hot bed:
https://www.youtube.com/watch?v=yxGM_-663uE

Re: Wanted - Taz 6 - Removable flexible bed mod ideas

Posted: Sat Mar 03, 2018 10:16 pm
by kcchen_00
Magnets would be great. So how would you attach to them to the print bed without obstructing the nozzle?

Re: Wanted - Taz 6 - Removable flexible bed mod ideas

Posted: Sun Mar 04, 2018 9:56 am
by nuroo
kcchen_00 wrote:
Sat Mar 03, 2018 10:16 pm
Magnets would be great. So how would you attach to them to the print bed without obstructing the nozzle?
The plan is to try and attach the magnets on the under side of the plate, same side as heating pad. Like the picture shown.

Re: Wanted - Taz 6 - Removable flexible bed mod ideas

Posted: Sun Mar 04, 2018 1:30 pm
by ocelot27
You have AC ruining through your heating pad???

N52 is the strongest readily available but by the quick test I posted they're not even necessary - the quench temp is well above 180°C - so unless you running your heating pad above that - wouldn't worry.

Yes the magnets go under the heating pad and pull through it to whatever you're trying to stick down - must obviously be ferromagnetic.

-jonh

Re: Wanted - Taz 6 - Removable flexible bed mod ideas

Posted: Sun Mar 04, 2018 2:33 pm
by kcchen_00
nuroo wrote:
Sun Mar 04, 2018 9:56 am

The plan is to try and attach the magnets on the under side of the plate, same side as heating pad. Like the picture shown.
Ah gotcha. Should work with magnets under the bed to affix a metal sheet above. The key may be finding an adhesive which can stand up to the flex and heat... maybe a RTV silicone.

I'd like to try a 5mm (.25in) PEI sheet with no backing on the modular system. Drill appropriate sized holes in the corners for magnets, would be an interesting way to attach on the steel sheet.

Re: Wanted - Taz 6 - Removable flexible bed mod ideas

Posted: Tue Mar 06, 2018 12:45 pm
by nuroo
@kcchen_00
I'd like to see it when its done. I'm sure can we come up with something if we put our heads together.

-------
On my Delta the print bed doesn't move at all. So the magnets and the screw cutouts have a fairly easy time holding the bed down and stopping any lateral movement. However on the Taz 6's bed, their can be large movements with sudden stops or alot of tiny movements of the print bed. This may lead to 2nd plate becoming misaligned if just held in place by magnets alone. Especially if a larger model is being printed. Maybe some sort of stand offs or notch/hook system? Just throwing ideas concerns.
Sorta how the washers serve as probe points but also hold the glass/pei in place........... That would hold the 2nd plate in place also, but who wants to have to unscew washers for every print?

Re: Wanted - Taz 6 - Removable flexible bed mod ideas

Posted: Tue Mar 06, 2018 1:09 pm
by nuroo
Saw this video today..... Its another video outlining our goal.

Random guy
https://youtu.be/IJ-WPo1rcI0

Makers Muse
https://youtu.be/eimw1ZWdrY4

Re: Wanted - Taz 6 - Removable flexible bed mod ideas

Posted: Wed Mar 07, 2018 12:15 am
by kcchen_00
nuroo wrote:
Tue Mar 06, 2018 12:45 pm
However on the Taz 6's bed, their can be large movements with sudden stops or alot of tiny movements of the print bed.
The bed corners should keep the plate from moving around. On the TAZ5, the metal pieces that hold the PEI/glass to the modular bed can be rotated out of the way for removal...

As for the 5mm PEI, it would be an expensive experiment. A sheet is ~$100. But then again if its not going to be nicked by tools, it becomes less of a consumable. Just need to scoff the surface every so often to reinvigorate the surface.


There is an old thread about testing with the PEI. Some posts cite that the PEI in thicker sheets bow when repeatedly heated, which is concerning. But there are positive posts from people that haven't experienced this. It could simply be laying the PEI down so that it curves into the metal bed, and the corners are secured by the metal fasteners.

Re: Wanted - Taz 6 - Removable flexible bed mod ideas

Posted: Wed Mar 07, 2018 9:49 pm
by kcchen_00
Here's an interesting epoxy to bond PEI to metal.
http://reltekllc.com/adhesivesforpolyetherimide.aspx

The BONDiT B-4x series offers good heat resistance, flexible/elongation. A bit pricey at $66 for 50mL and a minimum of $100 from the factory... so its $132 for epoxy.

Re: Wanted - Taz 6 - Removable flexible bed mod ideas

Posted: Wed Mar 14, 2018 1:48 pm
by ocelot27
If the steel is stainless it will likely not hold a magnet - some cheaper non-austenitic stainless will be magnetic...

Also why stainless - I would go with 1/8 or 3/16 aluminum plate - half the weight and a much much better conductor of heat...