Bed Adhesion/Surface Treatments (Is My Bed Attached to the Heat Spreader?)

[seedjar]

So, I haven't seen this mentioned anywhere, and it doesn't seem like it is necessarily a problem but... is my glass bed supposed to be adhered to the aluminum heat spreader? I went to take the glass off to wash it like I do the plates for my Orion but even with the clips turned aside, when I lift it, the heat spreader seems firmly attached. Maybe it's not an issue - I was just surprised to find it like that since I didn't read anything about it in the docs. I got some denatured alcohol and my bed is squeaky clean, better than ever. That's just what led me to thinking about adhesion treatments and bed liners.

I've seen some people using painter's tape and adarcher's bed clip mod for PEI. Back in the day it seemed like Kapton was the must-have bed treatment but now there's BuildTak and others. Which is the easiest to work with? And can I safely use the soapy-water squeegee technique to apply a liner if my glass is attached to the heated bed?

I print almost entirely in ABS on my Orion, mostly because prior to replacing the old hot end with the HE280, I got nothing but jams using PLA. I occasionally have specific need for the properties of ABS, but I wonder if I haven't been causing myself unnecessary grief printing everything with it - my apartment is kind of drafty and I get a fair amount of cracking/warping/peeling. I want to try PLA again now that I've got the Artemis (the Orion too, though it's out of commission at the moment.) I've used T-Glase and want to try other polycarbonates, as well as nylon and flexible materials. But if I had to choose one material for now, I think I'd stick with ABS. I understand that different liners (and bare glass alone) work well for different materials. I'm open to setting up my Artemis for one and my Orion for others.

Your experiences and thoughts would be appreciated. Thanks!

~Joe

[wepollock]

my glass bed supposed to be adhered to the aluminum heat spreader? ..... when I lift it, the heat spreader seems firmly attached. Maybe it's not an issue - I was just surprised to find it like that since I didn't read anything about it in the docs. I got some denatured alcohol and my bed is squeaky clean, better than ever.

In my case the clips have NO contact with the glass... when the bed heats up the glass seems to be locked in place w/o the clips; because of thermal expansion of the rubbery seemecnc decal against the glass. The adhesion is very good and firm even when the print is finished. The bed will float before the bed is heated.

The only layer shift I have gotten so far was because of some bad slicer gcode; so I would say the grip is firm enough. I have some untested (and unprinted) ideas to hold the bed in place should it be required in the future;

http://www.thingiverse.com/thing:2806519

AS to PLA vs ABS

I primarily print in PLA (and few times with PETG and even fewer times with Nylon). I found the nylon to be very moisture sensitive. The PETG was great and I have a few rolls in inventory lined up for future projects. I have some flexible projects lined up as well. What brand of flexible do the guys at Seemecnc use on the cable boots?

I never printed in ABS because I understand that it has some issues and concerns with fumes; and also because only one of my printers has an enclosed chamber. (feature request to Seemecnc - please design and sell an enclosure add on kit, and I would like spare effectors as well)

I am surprised you have had issues with PLA on at least five printers, I have printed some brands of PLA all the way down to 180 w/o any problems. The PLA's I am currently using include Novamaker (Orb Polymer 190), Ziro (real cheap but seems fine 205), Atomic, Makergeeks (220-235 degrees), Hatchbox, and Solutech. Color choice and price drive my decision making. I prefer to print a little high in terms of temperature. As G mentioned in another post, downward in temperature can eliminate strings, I would try going upward in temperature if you were experiencing jams.

Also, which brand of pla were you using?... I find that each brand and color to be a bit different in terms of the ideal printing temperature. Going up in temperature will make the PLA more fluid.

[seedjar]

I got that PLA back in 2014 shortly after I got my Orion. I don't remember the brand, but I do have it packed away somewhere, as I was going to try putting it through a dryer. I'm pretty sure I got it from SeeMeCNC, so I don't think it was a quality issue, but I can't rule it out. There were some problems with the liner in my hot end - after I fixed that, ABS worked, but PLA still jammed, so I just moved on and worked in ABS. Incidentally, from what I remember, turning the temperature up actually made the jams happen faster. Something about PLA having some strange viscosity/fluid friction properties. Now that I've got a metal hot end on the Orion I expect my next try to be easier.

As for the glass bed, I'm not worried about it shifting so much. It hadn't even occurred to me that might be a problem - how ever it's stuck on there, it's stuck pretty good, even if the clips don't apply much pressure. So I take it if PLA is your main thing, you just print on bare glass? It's so nice when it works... I'm looking forward to getting some PLA and T-Glass to try on the Artemis.

~Joe

[wepollock]

For me, PLA works almost every time..

[seedjar]

Yeah. In hindsight I am at least like 80% sure the problem was with my hot end. The Teflon tube had sloppy cut ends.
~Joe

[adarcher]

My glass bed came right off the aluminum... even has a bit of wiggle room. That's why I made that mod. Without those clips, my bed would move all over just from trying to print.

Originally I used a 1mm pei sheet, but now I got some of these from Amazon:
Wisamic PEI Sheet 12" x 12" with 3M Adhesive Tape Pre-applied, Ultem 1000, Ultem Sheet, Thickness 0.02 Inch/0.5mm - Amber
http://a.co/hfz3and

With those, it's not thick enough to really need the springs mod I did.

It's just a thin sheet on one side. If I need to print anything that doesn't or shouldn't be printer on pei, I can flip over to the clean glass side.

[seedjar]

Interesting. I might be mistaken, but I think my bed has been glued on or fused to the heat spreader somehow. Could the decal underneath be sticking them together? Seems strange.

There's a kind of telltale mark of some sort of adhesive running around the perimeter of the bed. The picture doesn't show it great, I'll see if I can get a clearer shot in the morning with a lens.

Nice tip about the thinner sheets, I almost ordered a 1mm sheet but I'll try the thinner ones first. I like the idea of flipping the glass, not sure I can do that until I figure out how to get mine to come loose though.

Thanks,
~Joe

[geneb]

The vinyl decal on the heat spreader does stick to the glass a bit, but should come off when it's cold. There's no adhesive holding it to the glass.

g.

[seedjar]

Would it be safe to use something to lever it up? If I grab it with my fingernails, the whole heat spreader assembly moves with it. When I really yank on it, the whole machine comes with it. I'm a little worried that I'm going to damage whatever is holding the heat spreader to the body. I've only tried to remove it when the bed is cool - room temperature - and it shows no sign of going anywhere. Would it be helpful to chill it somehow? Thanks.
~Joe

[geneb]

You could sand a wedge into the end of a popcicle stick and use that to separate the glass from the decal. Just make sure you don't accidentally get between the heat spreader and the decal instead.

g.

[seedjar]

Gene, do you know anything about the assembly process, specifically re: application of the vinyl decal to the heat spreader? The (possibly unlikely) scenario I am envisioning is that the vinyl decal is manufactured with some sort of film backing on the top face which is not heat-safe, that this film was accidentally not removed during assembly at SeeMeCNC, and that the first time the bed was heated (either by me or maybe they do that while testing the sub-assemblies in house) that this mystery film melted and fused the glass to the vinyl.

It's really stuck on there. My apartment is pretty cold - I live on the top floor, my windows are always cracked, and I do not turn the heat on. You know how the weather has been around here. The bed rarely reads above 70F when I switch it on; the air temperature often gets as low as 60F in the morning before TVs and computers and lights come on and push it back up.

How much stickiness should I expect from the vinyl at these temperatures? Is it advisable to try to forcibly remove the glass with the bed still installed? Seems sketchy to pry it up with so little clearance around the edge of the body. And the whole heat spreader/clip assembly seems to shift around with the glass when I push it. Would it be better to remove it from the frame first?

I didn't come up with the film explanation totally by imagination; there's a weird seam of something transparent underneath the glass. Notice how it crosses the through the print on the vinyl.

Thoughts? Thanks for looking.

~Joe

[seedjar]

Ah... well I tried to get my print-prying tool under there and all I got was glass-on-metal scratching noises. I will see if I can find something like a popsicle stick. At the very least it won't make that unpleasant noise. Thanks for the tip.
~Joe

[seedjar]

I don't have any popsicle sticks but I do have some cuticle sticks, which are like little sharpened dowels with a pointed end and a flat bias-cut end. Didn't budge it in the least, and I'm pretty sure I put enough force on it to break a popsicle stick. It's a mystery. :(
~Joe

[geneb]

You might try slipping a feeler gauge under the glass at the finger notch at the base of the X tower.

One thing to keep in mind - the glass is a very close fit within the chassis. Make sure that you're not accidentally catching the top surface of the glass under the lip of the chassis. I know that with mine, if I don't get it at the right spot, it won't come out because it does catch on the chassis.

g.

[seedjar]

I'll pick one up, but I'm not sure I'm going to be able to get that under the glass any better than my print-prying tool. I did manage to slip the blade under the glass, but it's not lifting up at all. And I managed to catch and mess up the decal, so I'm not sure I should push it in any further.

Edit: after trying it from another angle I managed to get it to come free. There was an extra layer of film on the decal underneath - it was pretty messed up and couldn't flatten it back out, so I peeled it off.
~Joe

[geneb]

I'll let them know. Thanks.

g.

[seedjar]

So that second layer of film was there by mistake? Haha! Vindication! Thanks Gene, I appreciate it.
~Joe

[geneb]

They're not sure where it came from. The decals don't come with a protective film over the top.

g.

[seedjar]

That's pretty strange. I should've snapped a pic I guess. I appreciate you looking in to it.
~Joe