Flat printbed

[René @3dnerd]

Hi,

I have also bad experiences with the warped PEI bed. Mine is not warped but twisted. Two diagonal edges lift up from the ground and do not get pressed down by the metal clips, because they are too far away from the edges (see attached image).
I have my Robox almost two weeks and I can only print small parts on certain areas of the bed.
Bigger parts fail due to non sticking to the ground everywhere. Using the full area of the printbed to print 210mm x 150mm is impossible!
This is often mentioned here in the forum that users have problems with warped printbed.
What I need is a flat printbed, because I need to print big parts. If it could not be done with PEI than any material is OK for me.
I can also work with hairspray to get better adhesion, this would be fine also.
Key is a flat printbed to get a good first layer ALL OVER THE PRINTBED.

So please give us a flat printbed…

 

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[Aimdy @mistsoul My Robox is a Blue Commercial Version]

@3dner, you could try to manually flatten the bed by gently flexing it, this was recommended in the following post and confirmed by Chris White:

http://www.cel-robox.com/forums/topic/include-tools-made-from-pagf-to-prevent-bed-and-nozzle-damages/#post-7658

Moh

[René @3dnerd]

Hi Aimdy,

I tried to bend, but no chance. This material is like a spring. If I bend it and release it again it jumps into the twisted position again.
So no chance 🙁

The problems is that my PEI bed is twisted. That means two diagonal edges always lift up, don’t touch the metal bet. Flipping makes no sense because then the opposite edges lift up. The metal clips which should keep down the PEI bed are too far away from the edges to press them down.

From my point of view the construction of the metal bed with the metal clips is not optimal. The metal clips are too high, so they don’t really fix the PEI bed.
I corrected this by putting some paper between the clip and the PEI bed. But still I can move the PEI bed on the metal bed. And as I told you this won’t solve the problem with the lifting edges.

I would prefer something like a ‘screwable clip/holder’ as replacement for the current clips. So I could turn down a screw to fix the PEI bed instead relying to the metal clips.

Is there any other way to untwist my PEI bed? May put it into an oven on a certain temperature and it will go flat?

• This reply was modified 1 year, 8 months ago by  René.

[click @click My Robox is a Green Kickstarter Limited Edition]

My PEI bed moves when cold. When warm/hot - it doesn’t move at all!

[Aimdy @mistsoul My Robox is a Blue Commercial Version]

I think it is supposed to move slightly, might does, but never tried to move ti when hot, I however have no issues with the prints sticking when all the temp conditions and calibrations are in order. Check with Cel before putting it in the oven.

Moh

[ned death @slarty]

Hi Clicky i had the same problem as you a twisted PEI board i made a ticket for it send them a pic of the offending part on a flat surface and CEL sent me a new PEI board. i think you should do the same by the sounds of it

[click @click My Robox is a Green Kickstarter Limited Edition]

When I am trying to print on one side of PEI prints seem close to acceptable. Middle of the PEI layers get slightly squashed and on the edges slightly thicker but I can print the reel sides without issues. I am not touching anything right now!!!

On the other hand, I would be more than glad to buy another PEI bed (given price is reasonable) and keep it as an replacement just in case…

[dave @dave]

+1, I can only print in the center without major problems on the first layer. The center prints out fine but the left and right, bottom and top layer either don’t stick or block the nozzle causing excessive blobbing and failed prints on layer 2. I think a glass sheet would be a good alternative, possibly with some extra sheet on top of it for adhesion without gluesticks/hairspray.

[click @click My Robox is a Green Kickstarter Limited Edition]

After sanding edges of PEI so it can move a bit when cold, it seems quite flat when warm. I’ve been printing last two weeks without any issues - Robox small reel takes quite lot of space on the bed (leaving only a few mm on each side).

[dave @dave]

Good to hear you can print close to the edges, I haven’t been able to do so from the beginning. I already sanded it down quite a bit but maybe it needs more.

[click @click My Robox is a Green Kickstarter Limited Edition]

Maybe it is not that good idea to overdo it. If it can move slightly (when cold) then sanding it even more might cause it moving too much even when hot…

[Phil Hoppes @rimcrazy My Robox is a Blue Commercial Version]

While I love this printer it is obvious in just the first few days that the clip method of attachment of the PEI Bed needs some serious re-engineering. Ben, the super Tech here in AZ came and scrunched the clips down so they would hold the PEI bed tight. Not two days later it is already loose again and I needed to re-compress the clips. Looks like I’m going to be doing this A LOT. This simply should not be an issue. 4 recessed screws in the corners or some kind of clamp that held it tight but allowed for some expansion should not be that difficult to design. As it is I would say that this is a pretty weak point in the design and should be addressed, hopefully with a design that can be retrofitted in the existing model.

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