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Well this is supposed to be a flat bottom box. But this ABS has different plans. Yikes.

Any tips? This was printed on a freshly cleaned glass, with fresh hairspray all over. The bed temp was 90 and didn't start to curl until the bottom was done and the sides of the box had begun. 4mm bottom.. I sliced through Cura 14.03 and tried to set a brim, but nothing printed.

Thanks

gajtguy wrote:Well this is supposed to be a flat bottom box. But this ABS has different plans. Yikes.

Any tips? This was printed on a freshly cleaned glass, with fresh hairspray all over. The bed temp was 90 and didn't start to curl until the bottom was done and the sides of the box had begun. 4mm bottom.. I sliced through Cura 14.03 and tried to set a brim, but nothing printed.

Thanks

Curl (1).JPG

What is the hairspray you are using, there are only a few types that work well.

The Aqua-Net Extra Super Hold. The bottle happens to be purple. Just like all the glue sticks I have as well. The glue sticks are just messier as you get clumps here and there.

I'd really like to get a brim going through Cura. Maybe I'll jump to the unreleased version to get that...
EDIT-Figured out that Brim Value doesn't work unless you set the 'Platform Adhesion type' to Brim. Duh.

gajtguy wrote:The Aqua-Net Extra Super Hold. The bottle happens to be purple. Just like all the glue sticks I have as well. The glue sticks are just messier as you get clumps here and there.

I'd really like to get a brim going through Cura. Maybe I'll jump to the unreleased version to get that...
EDIT-Figured out that Brim Value doesn't work unless you set the 'Platform Adhesion type' to Brim. Duh.

That is the exact hair spray I use and it works really well. Are you certain that the first layer is going down tight to the glass?

Try running your extrusion at 120% on the first layer so it really smooshes down the plastic. On a shape like that I would get that 2mm skirt working AND put a dab of ABS juice onto the corner of each skirt to really pin the corners down.

That combo works for me on a 50º heated bed with Elmers glue stick pretty much every time now. Plenty of plastic, decent skirt, blob of juice (just using a 1/4" kids art paintbrush) on the peak load points.

Check out the PEI thread. It is worth the read. I've been using it for a couple of months, over 300 hours. No need to apply any glues. I haven't even removed the build plate in that time.

gajtguy wrote:Well this is supposed to be a flat bottom box. But this ABS has different plans. Yikes.

Any tips? This was printed on a freshly cleaned glass, with fresh hairspray all over. The bed temp was 90 and didn't start to curl until the bottom was done and the sides of the box had begun. 4mm bottom.. I sliced through Cura 14.03 and tried to set a brim, but nothing printed.

Thanks

Curl (1).JPG

Sometimes I print mouse ears (circular patches about 20mmx20mmx.1mm thick) at each corner of a square-ish item. The ears provide additional adhesion and I can snap them off when the print is completed.

Thanks for the tips.

Holy1 - That is one long ass thread.. I think I fell asleep in the middle there somewhere.

Haha, it is so worth exploring it though

Holy1 wrote:Haha, it is so worth exploring it though

When using your PEI build plate with ABS what temperature are you running the bed at?

I use it at 100 for abs and 75 for pla. I know you can go cooler but I found at these temps I can start a print and walk away.

I was doing that for a while but found a couple of things:

1. Normal prints, bit of elmers glue, 50º was enough provided the nozzle was close enough to the plate on layer 1. Higher temperatures seemed to make adhesion worse, not better.
2. Big wide prints in ABS tend to curl as the ABS shrinks at different time intervals for each layer. Because physics. They shrink with quite a lot of force. Enough, as it turns out, to pull chunks out of your glass bed if you nail the first layer down hard on a big print and don't let it slip at all.

To keep my new (and quite expensive) glass intact, I've found it pays to let that first layer pop if it has to and then pin it down with juice after it's had a chance to relieve some of the strain. Pretty much painting on the mouse ears. After that, it's all pretty well behaved. Suspect that the tension trying to shrink the second layer heads up against the force of compressing the adhered (and already shrunk) first layer and settles somewhere in between, then the third layer just sits and behaves.

Captain, I've done the same - or alternatively, I've held the corners down with a long stainless 1mm rod. Kinda sucks that we have to do this but oh well.

I've ruined a few sheets of PEI - and consider it a major hassle due to the strength of the glue and the inevitable bubble or two.

I'm thinking my next move is window tint. John Oly always seems to be right. It's amazing.

JohnStack wrote:Captain, I've done the same - or alternatively, I've held the corners down with a long stainless 1mm rod. Kinda sucks that we have to do this but oh well.

I've ruined a few sheets of PEI - and consider it a major hassle due to the strength of the glue and the inevitable bubble or two.

I'm thinking my next move is window tint. John Oly always seems to be right. It's amazing.

John Oly always SEEMS to be right? Ask him - he is ALWAYS right!

Not always - I did get a suggestion to try mirror glass to replace my bed before I lashed out for more boro. Lasted one print before exploding. Given the price difference it was worth a try, but apparently the gentleman in question is actually human after all.

Sorry, Jon.



To me it seems things will go one of four ways:
- your adhesion isn't good enough to hold the significant tension of cooling plastic on a larger part and it will pop off the bed and curl;
- your adhesion is great and it doesn't pop/curl, but now you are challenged by the tension of cooling plastic exceeding the sheer strength of the glass;
- you replace the glass with something that will still stay flat with variable temps, still behave when you chip parts off or slip with the window scraper, and be strong enough to hold together under the tension of cooling plastic; or
- you design your part or process to allow for shrinkage and have internal stresses in the part take up the load of the shrinking plastic somehow.

Captain Starfish wrote:I've found it pays to let that first layer pop if it has to and then pin it down with juice after it's had a chance to relieve some of the strain. Pretty much painting on the mouse ears. After that, it's all pretty well behaved. Suspect that the tension trying to shrink the second layer heads up against the force of compressing the adhered (and already shrunk) first layer and settles somewhere in between, then the third layer just sits and behaves.

How do you line up the part again, once you let layer1 pop off? Just by eye using the skirt?
Do you alter the bed temp during this process?

I've got to make me some juice, hold the gin..

PS-we're still talking ABS techniques here, right?

If you haven't fixed the problem. I would re-calibrate you bed level , its possible , that your bed is convex and is causing and issue where the nozzle is pressing harder in the center causing the print to lift on corners. If you observe while it begins to print you should have and even layer and solid color , if it becomes more clear in spots then your bed is not properly calibrated.

Things to check to , your nozzle make sure it hasn't wiggled loose , re-calibrate you z height , check your belt tension. There is a chance that you are skipping steps and losing proper Z height.

gajtguy wrote:

Captain Starfish wrote:I've found it pays to let that first layer pop if it has to and then pin it down with juice after it's had a chance to relieve some of the strain. Pretty much painting on the mouse ears. After that, it's all pretty well behaved. Suspect that the tension trying to shrink the second layer heads up against the force of compressing the adhered (and already shrunk) first layer and settles somewhere in between, then the third layer just sits and behaves.

How do you line up the part again, once you let layer1 pop off? Just by eye using the skirt?
Do you alter the bed temp during this process?

I've got to make me some juice, hold the gin..

PS-we're still talking ABS techniques here, right?

If the whole part pops, you're stuffed. Can the print and start looking at bed levelling or a bigger brim or something. This is more for curly corners - they will usually start with one layer lifting as it pulls in. Re-pinning that corner as soon as it lifts with some juice, I find, generally fixes it for the rest of the print.

Would using a light coat of the ABS plastic dissolved in acetone and poured over the heated bed (when cold) and left to dry work ok on glass? It works a treat on bare aluminum. It's hard to get back off once the surface gets scratched up, but it does really hold like a champ. Very necessary for tall and narrow prints IMHO.

Yes. It works brilliantly, the best bed adhesion technique I've seen.

In fact, it works a little too well, as the various chunks in my first glass bed will attest.

Captain Starfish wrote:Yes. It works brilliantly, the best bed adhesion technique I've seen.

In fact, it works a little too well, as the various chunks in my first glass bed will attest.

You should be made to put a little label on the bottle of that stuff; USE AT YOUR OWN RISK!

Captain Starfish wrote:Yes. It works brilliantly, the best bed adhesion technique I've seen.

In fact, it works a little too well, as the various chunks in my first glass bed will attest.

YOWCH!! I never dreamed it would mess up a glass bed. That's amazing stuff. LOL

In fairness, the ratio I was using was less "ABS Juice" and more "ABS Mud", and the glass was covered in scratches created when I was learning the motor skills of using a razor to lift the skirt and brim of the parts I was printing early on.

I've never had the glass pulled off, but I've seen pictures of it several times, my assumption is that some glass has flaws that make it susceptible to this.
When I used ABS juice, I found thinner mixtures to be better.