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08-18-2015, 10:45 PM #1
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- Jun 2015
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How bad is inter-layer failure with ABS?
Hi.
I am thinking of moving to ABS, but I want to get something cleared up first.
I have read that the weak part of ABS parts is between layers. So ABS is stronger, but are the layer bonds weaker than PLA, so is it actually weaker in certain ways?
A PLA part that I just had fail was a 3/16 (5mm) diameter post protruding from a base, onto which a snug rotating arm is fixed. I'm not sure if it was from a torsion or straight shearing force, but it seems to have been a layer failure. Does ABS decrease this?
I realize that ABS has better material properties, but that doesn't help me if the layer bonds are weaker, and I am looking for a straight answer to this. Thank you!!
(By the way, in case anyone is wondering, I made the rotating part snug by making a bushing out of semiflex. It's going to be a toy with stiff movable parts. Also, there was a chamfer at the bottom of the post. It broke just above it.)Last edited by Wade3; 08-18-2015 at 11:03 PM.
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08-19-2015, 06:15 AM #2
Two things:
1. Layer separation is a risk with any FDM machine.
2. Layer separation is not an issue with the correct temperature, print speed, and cooling for your layer height and machine.
Well, three:
3. Small considerations when designing the part will make it print more easily and more reliably.
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08-19-2015, 07:37 AM #3
ABS is difficult to print well.
I talked with P Boichut of Spiderbot and in order to print ABS to a high quality standard with good repeatability, he intensely improved his machines : part heater, enclosure, fan to homogeneize temp, heated bed, ... the list is long and the development took time but you can find some info there : http://www.spiderbot.eu/en/products/upgrades.html
And the -impressive- result is there :
http://www.spiderbot.eu/en/media-inf...-pictures.html
Unless you have the means and dedication to strive to such pro results with ABS, why don't you try other high temp materials like PET ? PET is still heat resistant without that goddamned cooling shrinkage that makes it so hard with ABS.
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08-19-2015, 08:56 AM #4
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08-19-2015, 09:35 AM #5
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08-19-2015, 10:34 AM #6
I have found post-production with Acetone or Acetone/ABS slurry applied with a brush greatly strengthens the layer bonds.
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08-19-2015, 11:54 AM #7
ABS Warps more than PLA ,
very obvious difference when doing large base area objects.
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08-19-2015, 04:23 PM #8
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- Jun 2015
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I've got a Craftbot with a heated build plate, insulated bed, glass plate with glue stick, and heating chamber in the works. My original question stands:
Does ABS have weak layer bonds compared to PLA?
If I stress test an ABS part in shear, will it fail before my PLA part fails?Last edited by Wade3; 08-19-2015 at 04:40 PM.
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08-19-2015, 04:47 PM #9
- Join Date
- Apr 2015
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- 14
Scientifically I can't say but from a practical standpoint I see no difference.
If my printer and software are tweaked correctly they both print the same. It takes a little more work to get ABS to be just right but is worth the effort in my opinion.
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08-19-2015, 06:40 PM #10
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- Jun 2015
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Hmm.. Well, I just found this page from a google search. It's one guy's word, but he is authoritatively stating my suspicion.
http://robosavvy.com/forum/viewtopic.php?t=9655
"Myth 3: ABS is much stronger than PLA
This is the most recurring one and it's also the most inaccurate: if you compare injection molded parts, ABS parts are indeed stronger than it's PLA counterparts; however we're doing 3D Printing layer by layer, not injection molding and this changes things considerably:
A 3D printed part in PLA is MUCH stronger than a part printed in ABS. This is because PLA has significantly stronger layer bonding than ABS."
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I'm going to start looking at other filaments. But would any of them be an improvement? Maybe inserting metal pins is the way to go. Edit: Cool, jimc, I will look into that!
New to 3d printing looking for...
05-20-2024, 12:56 AM in Tips, Tricks and Tech Help