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Bed adhesion issues

Posted by Parabolic 
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Parabolic
Bed adhesion issues
October 16, 2011 01:54PM
Ok - finally got some decent prints going on - somewhat calibrated. But im having a problem with my pla seperating from the heated bed after about 5-6mm of height. Im printing on the retail heat bed on glass on kapton. Im also cleaning the kapton after prints with foaming glass cleaner. Should i be changing the kapton? Ive tried using a hotter temp on the board - doesnt seem to solve it. I hate getting these half built parts that look great only to have to pitch them cause they cant stick to the damn bed.
Ive looked around and everyones post seems to have diffrent answers - opinions. So I figured Id ask. Should I be printing a heavier 1st layer? It seems like its stuck good then the edges start to warp up. then she lets loose.
Thanks!
Jeff
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Pointedstick
Re: Bed adhesion issues
October 16, 2011 02:35PM
What's the temperature on your heated bed? Most people run it at about 60º. Also, you can probably ditch the Kapton. It should print directly on the glass just fine.
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Parabolic
Re: Bed adhesion issues
October 16, 2011 02:43PM
well,
I dont know if I messed up my sfact settings or what - I printed a few things out with no problems (although not perfect), but now I cant even get this idler to print without popping off. The temp is set at 60 deg.
Im thinking of just reloading sfact and starting agian..... not sure if im not laying down enough plastic or the bed surface or the temp of the filiment. My best print actually was printing pla using the Abs settings - perfect lines - actually stuck to the tape.....
Im using prusas recommended surface (kapton over glass and heated board). If I go with just glass, what do I clean it with- that will cause the most adhesion?
Thanks
JEff
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NelsonRap
Re: Bed adhesion issues
October 16, 2011 03:20PM
I print PLA onto glass with NO kapton on my Mendel and at 55C it sticks so well I have to remove the glass and let it cool down before the print will come off. I found using any sort of tape i got lifting of the tape itself from the bed

__________________________________________________________________________
Experimenting in 3D in New Zealand
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Pointedstick
Re: Bed adhesion issues
October 16, 2011 03:50PM
If the same settings that worked before don't work anymore, it's probably not SFACT's fault. Is it possible that your bed has gotten un-leveled or fallen in height a millimeter or two? That would cause the extruded plastic to not be smooshed onto the bed, causing poorer adhesion.
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Parabolic
Re: Bed adhesion issues
October 16, 2011 04:28PM
I talked to Spacexula in the IIrc and he helped me figure out it was my raft and ist layer settings - wasnt printing "wide" enough on the first layer.
He also had me slow down my 1st later speeds as well.
working good so far!
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bsutton
Re: Bed adhesion issues
October 16, 2011 09:29PM
For the record I'm successfully printing with the following settings:

Prusa
Mk 1 hotbed.
Glass bed with NO kapton
No raft.

I've used temperatures at 95c and 50c. Both work but the 50c stick much better. I've had a little warp on larger pieces at 95c. I'm hoping the lower temp (50c) will fix this but haven't had time to test it.

I'm just cleaning the glass with Windex (window cleaner) but it must be really clean (a finger print is enough to cause problems). If its not clean you get little areas that sort of bubble off the surface.
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NelsonRap
Re: Bed adhesion issues
October 16, 2011 10:35PM
I clean my glass with methylated spirits because that's all I had at the time and it works

__________________________________________________________________________
Experimenting in 3D in New Zealand
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jcabrer
Re: Bed adhesion issues
October 18, 2011 01:12PM
PLA prints fine on bare glass, so there is no need for Kapton, as others have mentioned.

Isopropyl (isopropynol?) alcohol 70%+ is good for cleaning the glass. Acetone is not as good. There is science behind this, but not that I can understand it or explain it. Lower alcohol concentrations have too much water, and may leave residue.

Fingerprints on the glass will always cause problems, so try not to touch it. It takes several cleanings to get all the oils off the surface. When cleaning wipe in one direction only, to prevent just smearing the oils around.

The adhesion window for PLA is between 60'C and 80'C. Too much below, or above, and the stuff will come off. PLA does not have the same warping problems as ABS because it cools more slowly, allowing tension to be released, and I suppose it also shrinks less during cooling.
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nophead
Re: Bed adhesion issues
October 18, 2011 03:41PM
I don't think it has anything to do with how quickly it cools. PLA warps less because it has both a lower thermal expansion and a very low glass transition temperature. It only exerts force on the layer below when it is below the glass transition, because above it it is like jelly, and that is only about 50C, so it shrinks very little between that and room temperature.

ABS has a glass transition at about 80C so you have about twice the temperature drop as well as a much bigger thermal coefficient.

[www.hydraraptor.blogspot.com]
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jsadusk
Re: Bed adhesion issues
October 18, 2011 05:56PM
jcaber, I should point out that while Isopropyl alcohol is great for cleaning glass for printing PLA, its useless for getting ABS residue off of Kapton or PET. For that acetone seems to work best.
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brnrd
Re: Bed adhesion issues
October 18, 2011 05:59PM
I've noticed that isopropyl alcohol does a good job at removing oily residue from the surface while ABS dissolves away ABS residue. So, when I was printing PLA on glass, I used both. Washing the glass with diswashing detergent is also a good way to remove oily residue from it.
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davejones
Re: Bed adhesion issues
October 18, 2011 06:34PM
I print using PLA onto bare tempered glass. Glass surface temperature 60c.
Initially cleaned glass with dishwasher detergent then methylated spirits now I just use meths between prints.
The only times I've had warping or adhesion problems is if I don't clean the glass (with meths) for several prints.
I once accidently cleaned the glass with automotive wax and grease remover (same style bottle but different label) and I couldn't get anything to stick until I realised my mistake and re-cleand the glass with detergent and then meths.
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nophead
Re: Bed adhesion issues
October 18, 2011 06:52PM
I find Isopropyl alcohol leaves a white residue which reduces adhesion. Can be useful as sometimes it stick so well I smash the parts getting them off. Meths seems better for removing grease without leaving residue.

[www.hydraraptor.blogspot.com]
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Anx
Re: Bed adhesion issues
October 19, 2011 03:21AM
Forgive my ignorance, but what is Meths? smiling smiley
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rhmorrison
Re: Bed adhesion issues
October 19, 2011 03:40AM
meths [mɛθs]
n
(Chemistry / Elements & Compounds) Chiefly Brit, Austral, and NZ an informal name for methylated spirits.
i.e. Methanol plus additives is "Denatured alcohol".

At least I ASS-U-ME that is what they mean and not what US Americans understand as meths!

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse
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nophead
Re: Bed adhesion issues
October 19, 2011 05:07AM
Yes in the UK the government insist that ethanol sold without duty must be made deadly poisonous by adding some methanol. They also add purple die and a horrible smell and taste to warn people. Still some people drink it and the government is sentencing them to death for tax evasion.

[www.hydraraptor.blogspot.com]
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NelsonRap
Re: Bed adhesion issues
October 20, 2011 02:15AM
nophead Wrote:
-------------------------------------------------------
> Yes in the UK the government insist that ethanol
> sold without duty must be made deadly poisonous by
> adding some methanol. They also add purple die and
> a horrible smell and taste to warn people. Still
> some people drink it and the government is
> sentencing them to death for tax evasion.

Much the same here in NZ I am originally from the UK and when I came here was surprised to see Meths exactly the same as back in the old country. I have only ever cleaned my glass with meths and nothing else, it is ordinary 3mm glass nothing flash that I cut myself due to being a picture framer as well. I find if I leave my prints to go cold they just lift off that's for PLA I have never used ABS so don't know about that

__________________________________________________________________________
Experimenting in 3D in New Zealand
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DeuxVis
Re: Bed adhesion issues
October 22, 2011 06:21AM
Parabolic, if you still want to print pla without a heated bed, give a try to 3M/Scotch blue tape - I just did myself, and it does miracles to avoid pla warp.
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Parabolic
Re: Bed adhesion issues
October 22, 2011 07:56PM
Hey - was doing great! had no issues, until today. I tried to build my first "tall" piece (linear x holders), and just as its getting up to the "bridging" area the damn thing came unstuck from the bed! So I reprinted it - AGAIN! in the same damn spot!!
is the pla cooling to much by that point? should I bump the bed up to ABS temps?
I did try blue tape - couldnt even get the first layer to stick....
Is PLA just bad news to print with? Will I have better luck with Blue tape?
Jeff
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Nudel
Re: Bed adhesion issues
October 22, 2011 09:39PM
I have printed many different variations of PLA successfully on 4mm heated glass @~40C since may. After trying several other methods with various luck, glass is the best and simplest method I've used.

Perhaps the glass is getting a bit greasy, have you cleaned it lately?

Also the z endstop may have been knocked out of alignment, I usually need to squish the first layer a bit to get good adhesion.

It happens at the same point on the model because the nozzle is catching the print and knocking it off. I solved it by upping my layer height by only 0.01mm, to 0.36mm (0.5mm nozzle).

Edited 1 time(s). Last edit at 10/22/2011 09:41PM by Nudel.

--
-Nudel
Blog with RepRap Comic
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Parabolic
Re: Bed adhesion issues
October 22, 2011 09:47PM
Im running kapton over glass - yup cleaned it with alcohol every time. My first layer is pretty quished already...
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Anthong Redbeard
Re: Bed adhesion issues
October 22, 2011 10:03PM
Mine WAS doing decent as PCB + glass + kapton... then it got a lot colder in the house and it warps a LOT more, gonna try to cover it up with some vinyl sheeting to make a flexible heated chamber, and at the very least prevent drafts
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NelsonRap
Re: Bed adhesion issues
October 23, 2011 02:07AM
I had a standard X motor bracket lift off in one corner yesterday under where the motor bolts, this is the first time this has happened for over 6 months, I'm wondering if I didn't clean that spot on the glass I can't think of any other reason. Luckily the piece is still perfectly usable

__________________________________________________________________________
Experimenting in 3D in New Zealand
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misan
Re: Bed adhesion issues
October 23, 2011 09:07AM
I'm using duct temp on my aluminium (non-heated) bed (It was the tape I had at hand). My blue PLA is sticking to it very well (though my prints till now are not very tall and not longer than five minutes of print time).

misan
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misan
Re: Bed adhesion issues
October 29, 2011 06:26PM
I'm afraid vinyl duct tape is not the answer for large prints. I'm also having adhesion problems with large prints angry smiley

Edited 1 time(s). Last edit at 10/29/2011 06:26PM by misan.
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jcabrer
Re: Bed adhesion issues
October 29, 2011 07:01PM
60'C might be marginally too cold for your particular machine. Bump it up to 70'C and see if things improve. My experience has been that there is about a 30 degree range where PLA stick well. Anything too far outside that range, and it peels. For me the center is 75'C, so I can got from about 60'C to 90'C. The high end of this range gives trouble when printing smaller parts.
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Sublime
Re: Bed adhesion issues
October 29, 2011 07:14PM
I just built a heated bed two weeks ago. When I try printing directly on the glass at any temperature I have adhesion problems so I went back to printing on Blue painters tape (no Kapton yet). This works really well for me but any hotter than 50c makes the part fall off and lift really easily. When I print at 45c it sticks so well I only get one print per tape application.

This was printed as i just described. It measures 100 x 100 x100mm and did not warp.


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Tantillus.org Mini Printable Lathe How NOT to install a Pololu driver

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Parabolic
Re: Bed adhesion issues
October 29, 2011 07:43PM
Well, I managed to print both x end brackets (measurig about 70mm tall) with no issues! they seemed to stick real well.
Im using Kapton tape over glass - heated bed - cleaning between prints using denatured alcohol. bed is set at 60 degrees c.
So its been ok with this formula - for now.
Jeff
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brnrd
Re: Bed adhesion issues
October 29, 2011 07:46PM
With kapton tape over glass, you're missing a big advantage of using glass: easy release of the printed part upon cooling the glass. And you still have the disadvantage of bubbles accumulating under the kapton tape.
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