Printing with PLA vs ABS demystified
Printing with PLA vs ABS demystified
by PedroR
Tue Jul 09, 2013 5:27 pm
Hi all
Based on customer feedback I felt it was important to clarify a few key points about PLA and also the advantages and disadvantages of PLA vs ABS when used on FFD printers (such as the Makerbot Replicator, UP!, etc.).
Firstly I'd like to say that PLA is a very strong and very durable material.
There are a few myths surrounding PLA:
Myth 1: PLA will dissolve in water and/or will degrade in moist environments.
This not true.
The plastic that dissolves in water is PVA, not PLA.
Myth 2: Because PLA is biodegradable it will self destruct and just become undone in a matter of months
Again, not true.
"Biodegradable" means the product is strong and performs its function very well but when you throw it in a landfill it will ultimately break down.
This is actually much more environmentally responsible than using ABS which takes over a hundred years to break down. In addition PLA is made from natural resources such as corn starch or sugar cane.
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.
About layer bonding: unlike injection molding, FFD printers print layer by layer so layer bonding is what determines the part strength.
If you're familiar with 3D Printing you'll know that the strength of a part changes depending on the direction: if you pull perpendicularly to the Z axis (where layers are deposited), they will detach; if you pull in any other direction the part is much stronger. It behaves a bit like wood.
Because PLA has much stronger layer bonding it's almost as strong in all directions (even when pulled in the Z axis).
ABS on the other hand, will detach layers much faster and much easily than PLA, making 3D printed ABS parts less strong. (they're not weak either; PLA parts are just stronger).
PLA vs ABS in practice:
Rigidity:
PLA is a much more rigid material compared to ABS. If you compare ABS and PLA by applying a progressive force, ABS will start to bend and finally will break; while ABS is bending, PLA on the other hand will hold it's shape (it's very rigid and doesn't flex).
After a certain point it will eventually break before bending. You often need more force to break a PLA part than an ABS one especially if you have a thick part.
Shrinkage factor:
PLA has a much lower shrinkage factor than ABS.
In practice this means it's MUCH easier to use in 3D printers: unlike ABS, PLA deforms significantly less and suffers from very little layer detachment leading to a much higher success rate on prints.
With ABS, even a relatively small part will deform when printing if you don't have a heated bed and/or a heated building environment.
Painting:
Both materials - PLA and ABS - can be painted andpost processed (sanded)
Bio degradability
PLA is a bio degradable material. This means it will resist for very long in indoors use and occasional outdoors use but permanent exposure to the elements will eventually start to degrade it.
It is not suitable, for example, for parts that need to stay outdoors 365 days a year; for these applications ABS is preferable.
From what we've seen over the years we've been selling 3D Printers there are 3 very specific cases where ABS is preferable over PLA:
Case 1: Outdoors use
We've had a customer of ours that purchased a 3D printer to build enclosures for electronics modules that were going to be left outside for several years.
In this case ABS is better: by not being bio degradable ABS ensures that it will retain its properties exposed to the elements outdoors for several years.
Case 2: Parts that need to flex (for fittings for example)
Another customer of ours needed to build supports for DIN rails. The support needed to flex enough to fit into the DIN rail.
We printed the same part in PLA and ABS. PLA, due to its rigidity, wouldn't flex so ABS was the material of choice because of it's flexibility.
One important note here: the part would flex because it had a thin back plate; if you have a thick ABS part it will obviously not bend as they needed.
Case 3: temperature
We've never had a customer with this need but it's worth mentioning: ABS has a higher melting temperature so if you have applications that need to deal with temperatures above 60ºC, than ABS is also preferable over PLA because ABS has higher glass point and melting point.
All in all PLA is not a "one size fits all" but it will meet the needs of 95% of the customers and - from experience - it is so much easier to use and print compared to ABS.
The fact that is has a low shrinkage factor means parts deform significantly less which results in much higher success rates in 3D prints.
You'll find yourself using your 3D printer a lot more and getting a lot more work done. We have several printers in the lab and we use PLA for 99.5% of the parts we produce, even for our 1m tall Humanoid.
For some reason a myth was built around PLA that steers people away from it and leads them to blindly believe that ABS is a better material for 3D printing. This is not the case for all the reasons above.
I hope this posts helps clear this out.
Taking our offer of 3D Printers, the Replicator 2 (for PLA only) is a great machine. It is designed to provide the smoothest print experience possible in the current state of the technology.
That's the printer we use the most in our lab. That and an old wooden Replicator DUAL (with a number of mods from thingiverse to print PLA and ABS much better)
Regards
Pedro.
Based on customer feedback I felt it was important to clarify a few key points about PLA and also the advantages and disadvantages of PLA vs ABS when used on FFD printers (such as the Makerbot Replicator, UP!, etc.).
Firstly I'd like to say that PLA is a very strong and very durable material.
There are a few myths surrounding PLA:
Myth 1: PLA will dissolve in water and/or will degrade in moist environments.
This not true.
The plastic that dissolves in water is PVA, not PLA.
Myth 2: Because PLA is biodegradable it will self destruct and just become undone in a matter of months
Again, not true.
"Biodegradable" means the product is strong and performs its function very well but when you throw it in a landfill it will ultimately break down.
This is actually much more environmentally responsible than using ABS which takes over a hundred years to break down. In addition PLA is made from natural resources such as corn starch or sugar cane.
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.
About layer bonding: unlike injection molding, FFD printers print layer by layer so layer bonding is what determines the part strength.
If you're familiar with 3D Printing you'll know that the strength of a part changes depending on the direction: if you pull perpendicularly to the Z axis (where layers are deposited), they will detach; if you pull in any other direction the part is much stronger. It behaves a bit like wood.
Because PLA has much stronger layer bonding it's almost as strong in all directions (even when pulled in the Z axis).
ABS on the other hand, will detach layers much faster and much easily than PLA, making 3D printed ABS parts less strong. (they're not weak either; PLA parts are just stronger).
PLA vs ABS in practice:
Rigidity:
PLA is a much more rigid material compared to ABS. If you compare ABS and PLA by applying a progressive force, ABS will start to bend and finally will break; while ABS is bending, PLA on the other hand will hold it's shape (it's very rigid and doesn't flex).
After a certain point it will eventually break before bending. You often need more force to break a PLA part than an ABS one especially if you have a thick part.
Shrinkage factor:
PLA has a much lower shrinkage factor than ABS.
In practice this means it's MUCH easier to use in 3D printers: unlike ABS, PLA deforms significantly less and suffers from very little layer detachment leading to a much higher success rate on prints.
With ABS, even a relatively small part will deform when printing if you don't have a heated bed and/or a heated building environment.
Painting:
Both materials - PLA and ABS - can be painted andpost processed (sanded)
Bio degradability
PLA is a bio degradable material. This means it will resist for very long in indoors use and occasional outdoors use but permanent exposure to the elements will eventually start to degrade it.
It is not suitable, for example, for parts that need to stay outdoors 365 days a year; for these applications ABS is preferable.
From what we've seen over the years we've been selling 3D Printers there are 3 very specific cases where ABS is preferable over PLA:
Case 1: Outdoors use
We've had a customer of ours that purchased a 3D printer to build enclosures for electronics modules that were going to be left outside for several years.
In this case ABS is better: by not being bio degradable ABS ensures that it will retain its properties exposed to the elements outdoors for several years.
Case 2: Parts that need to flex (for fittings for example)
Another customer of ours needed to build supports for DIN rails. The support needed to flex enough to fit into the DIN rail.
We printed the same part in PLA and ABS. PLA, due to its rigidity, wouldn't flex so ABS was the material of choice because of it's flexibility.
One important note here: the part would flex because it had a thin back plate; if you have a thick ABS part it will obviously not bend as they needed.
Case 3: temperature
We've never had a customer with this need but it's worth mentioning: ABS has a higher melting temperature so if you have applications that need to deal with temperatures above 60ºC, than ABS is also preferable over PLA because ABS has higher glass point and melting point.
All in all PLA is not a "one size fits all" but it will meet the needs of 95% of the customers and - from experience - it is so much easier to use and print compared to ABS.
The fact that is has a low shrinkage factor means parts deform significantly less which results in much higher success rates in 3D prints.
You'll find yourself using your 3D printer a lot more and getting a lot more work done. We have several printers in the lab and we use PLA for 99.5% of the parts we produce, even for our 1m tall Humanoid.
For some reason a myth was built around PLA that steers people away from it and leads them to blindly believe that ABS is a better material for 3D printing. This is not the case for all the reasons above.
I hope this posts helps clear this out.
Taking our offer of 3D Printers, the Replicator 2 (for PLA only) is a great machine. It is designed to provide the smoothest print experience possible in the current state of the technology.
That's the printer we use the most in our lab. That and an old wooden Replicator DUAL (with a number of mods from thingiverse to print PLA and ABS much better)
Regards
Pedro.
Last edited by PedroR on Wed Jul 10, 2013 10:32 am, edited 1 time in total.
by PedroR
Wed Jul 10, 2013 11:12 am
Hi all
I'm glad I could be of help!
I felt like I was turning into a K7 tape on the phone with customers
explaining this.
I don't where the myths about PLA come from though but I'm happy we know have a reference point.
In other news, we've received today samples for a PLA compound from Colourfabb. This is basically PLA mixed with an additive (PHA) to make it less brittle and slightly more flexible.
It has all the same properties of PLA (melting points, biodegradability, etc.) with the main difference being less brittle and rigid, coming closer to the behavior of ABS.
It also comes in really beautiful colour shades.
I don't have a lot more to say right now but hopefully we'll be posting about our tests soon.
We're running prints on the Replicator 2 to access the compatibility, print quality and part strength to make a comparison with both pure PLA and ABS.
Regards
Pedro.
I'm glad I could be of help!
I felt like I was turning into a K7 tape on the phone with customers
explaining this.
I don't where the myths about PLA come from though but I'm happy we know have a reference point.
In other news, we've received today samples for a PLA compound from Colourfabb. This is basically PLA mixed with an additive (PHA) to make it less brittle and slightly more flexible.
It has all the same properties of PLA (melting points, biodegradability, etc.) with the main difference being less brittle and rigid, coming closer to the behavior of ABS.
It also comes in really beautiful colour shades.
I don't have a lot more to say right now but hopefully we'll be posting about our tests soon.
We're running prints on the Replicator 2 to access the compatibility, print quality and part strength to make a comparison with both pure PLA and ABS.
Regards
Pedro.
by mantrid
Wed Jul 10, 2013 1:06 pm
Pedro
Many thanks for the excelent overview.
It certainly does sound like PLA is a more flexible (in terms of usage not bending!) material for 3D printing.
My only question at this point would be - how biodegradable?
i.e. what would be the expected life in bright sunlight of a part of certain
thickness before it started to loose cohesion?
Your example is one not to take risks with of course - but I woulder what uses PLA could be put to outdoors before problems were expected.
(I'd also like info on sea water exposure)
I don't expect you to answer that! I'm just saying thats the info I'd be looking for before making a final decision on anything.
Many thanks for the excelent overview.
It certainly does sound like PLA is a more flexible (in terms of usage not bending!) material for 3D printing.
My only question at this point would be - how biodegradable?
i.e. what would be the expected life in bright sunlight of a part of certain
thickness before it started to loose cohesion?
Your example is one not to take risks with of course - but I woulder what uses PLA could be put to outdoors before problems were expected.
(I'd also like info on sea water exposure)
I don't expect you to answer that! I'm just saying thats the info I'd be looking for before making a final decision on anything.
by PedroR
Wed Jul 10, 2013 6:32 pm
Hi matrid
As you guessed, it's hard for us to determine the ratio at which a PLA degrades.
Especially because this is the range of several months (likely a few years).
If you have a particular application in mind it's usually easier to take that and do an analysis.
For example, if you're going to expose something to sea water, we'd definitely recommend ABS.
However what we see in practice is people using these 3D printers for prototyping and small batch runs.
I can tell you from experience that using ABS real pain, especially if you want to make something that larger than 12cm X 12cm. (average values)
The peeling and cracking is a nightmare. If you print the same thing in PLA it should come out like a charm.
Most FFD printers (like the Replicator and UP) can, in reality print both ABS and PLA.
The Replicator 2 extruder for example, can extrude ABS. However the Replicator 2 can't print ABS parts. This is because it doesn't have a Heated Build Plate.
The Heated Build Plate is essential for ABS prints because it will relax the tensions on the lower layers, helping with slower cooling and deformation.
Many 3D printers have the option of getting a Heated Bed add-on to enable the use of ABS.
(it's not the case of the Replicator 2 though! to be clear the Replicator 2 is a PLA only machine and there is no official way to install a Heated Bed and upgrade it to be able to print ABS).
If you feel you might need ABS, this could be a way to go.
Regards
Pedro.
As you guessed, it's hard for us to determine the ratio at which a PLA degrades.
Especially because this is the range of several months (likely a few years).
If you have a particular application in mind it's usually easier to take that and do an analysis.
For example, if you're going to expose something to sea water, we'd definitely recommend ABS.
However what we see in practice is people using these 3D printers for prototyping and small batch runs.
I can tell you from experience that using ABS real pain, especially if you want to make something that larger than 12cm X 12cm. (average values)
The peeling and cracking is a nightmare. If you print the same thing in PLA it should come out like a charm.
Most FFD printers (like the Replicator and UP) can, in reality print both ABS and PLA.
The Replicator 2 extruder for example, can extrude ABS. However the Replicator 2 can't print ABS parts. This is because it doesn't have a Heated Build Plate.
The Heated Build Plate is essential for ABS prints because it will relax the tensions on the lower layers, helping with slower cooling and deformation.
Many 3D printers have the option of getting a Heated Bed add-on to enable the use of ABS.
(it's not the case of the Replicator 2 though! to be clear the Replicator 2 is a PLA only machine and there is no official way to install a Heated Bed and upgrade it to be able to print ABS).
If you feel you might need ABS, this could be a way to go.
Regards
Pedro.
by Gort
Wed Jul 10, 2013 8:07 pm
PedroR, lots of good information but I will stick with ABS for robot brackets.
Yes, PLA is great for large objects.
What about the Replicator 2X? It is designed to be a ABS printer. I have not used one yet so I am not sure how well it works. It also should be able to print using PLA.
The new PLA you talked about sounds interesting.
Yes, PLA is great for large objects.
What about the Replicator 2X? It is designed to be a ABS printer. I have not used one yet so I am not sure how well it works. It also should be able to print using PLA.
The new PLA you talked about sounds interesting.
by PedroR
Thu Jul 11, 2013 12:11 pm
Hi Gort
I haven't brought up the 2X for two reasons.
The main one is that - as you may have known - Makerbot temporarily suspended taking orders for the 2X a couple of weeks ago. They're taking orders again for delivery in 10-12 weeks.
[ UPDATE ] Replicator 2X shipments have resumed and the mahcines are available from our online store http://robosavvy.com/store/replicator [ /UPDATE ]
The other thing with the 2X is that it is a "experimental platform". Makerbot marketing is very aggressive at promoting their printers almost as easy to use as their 2D counterparts (inkjets, laserjets).
While this is pretty much the case with the Replicator 2 - after you go through the learning curve though - with ABS (and the 2X) it's a different story. (as you probably know from using ABS it is a material that can be temperamental although uninformed users usually blame it on the machine not the material).
It's a great machine to try out new materials and experiment with but it can be a frustrating experience if you have no previous experience with 3D printing and you try pushing the envelope.
The other thing with the 2X is that it doesn't have the side fan to cool the layers. This means that printing PLA in the 2X at 100 microns doesn't have the same great finish as it does in the R2.
ABS works great at 100 microns on the 2X; to do PLA at 100 microns you really need the layer cooling fan which the 2X doesn't have.
Make no mistake: the 2X _can_ do PLA but, from what I've seen, the best finish in PLA, on the 2X, is at about 200 microns.
[ UPDATE ] The latest Makerbot sales material for the 2X (after temporary sales interruption) mentions only ABS now. While many different materials can be used with the Replicator 2X including PLA, as I explained ABS is really the material to use with the 2X if you want to go for the best quality.
You can still go for any other material on the 2X if you're Macguyver or Doc Brown as they say in their video. [ /UPDATE ]
All in all, the Rep 2 is much more of a consumer product and the 2X in more of a specialized product for expert 3D print users.
In the R&D lab - to give you an idea - we have one R2X and four R2s simply because the R2 is more practical.
We use the 2X for ABS prints and other specialized materials.
The new materials we got from Colourfabb (PLA with additives) seem to close the gap a little more between PLA and ABS: it's more flexible (ie less rigid and in consequence less brittle in thin sections) while maintaining all the advantages of PLA (stronger layer bonding, low shrinkage factor).
A good test is when you bend the filament, regular PLA breaks; Colourfabb doesn't break (it flexes in a behavior closer - not equal but closer - to ABS).
Regards
Pedro.
I haven't brought up the 2X for two reasons.
The main one is that - as you may have known - Makerbot temporarily suspended taking orders for the 2X a couple of weeks ago. They're taking orders again for delivery in 10-12 weeks.
[ UPDATE ] Replicator 2X shipments have resumed and the mahcines are available from our online store http://robosavvy.com/store/replicator [ /UPDATE ]
The other thing with the 2X is that it is a "experimental platform". Makerbot marketing is very aggressive at promoting their printers almost as easy to use as their 2D counterparts (inkjets, laserjets).
While this is pretty much the case with the Replicator 2 - after you go through the learning curve though - with ABS (and the 2X) it's a different story. (as you probably know from using ABS it is a material that can be temperamental although uninformed users usually blame it on the machine not the material).
It's a great machine to try out new materials and experiment with but it can be a frustrating experience if you have no previous experience with 3D printing and you try pushing the envelope.
The other thing with the 2X is that it doesn't have the side fan to cool the layers. This means that printing PLA in the 2X at 100 microns doesn't have the same great finish as it does in the R2.
ABS works great at 100 microns on the 2X; to do PLA at 100 microns you really need the layer cooling fan which the 2X doesn't have.
Make no mistake: the 2X _can_ do PLA but, from what I've seen, the best finish in PLA, on the 2X, is at about 200 microns.
[ UPDATE ] The latest Makerbot sales material for the 2X (after temporary sales interruption) mentions only ABS now. While many different materials can be used with the Replicator 2X including PLA, as I explained ABS is really the material to use with the 2X if you want to go for the best quality.
You can still go for any other material on the 2X if you're Macguyver or Doc Brown as they say in their video. [ /UPDATE ]
All in all, the Rep 2 is much more of a consumer product and the 2X in more of a specialized product for expert 3D print users.
In the R&D lab - to give you an idea - we have one R2X and four R2s simply because the R2 is more practical.
We use the 2X for ABS prints and other specialized materials.
The new materials we got from Colourfabb (PLA with additives) seem to close the gap a little more between PLA and ABS: it's more flexible (ie less rigid and in consequence less brittle in thin sections) while maintaining all the advantages of PLA (stronger layer bonding, low shrinkage factor).
A good test is when you bend the filament, regular PLA breaks; Colourfabb doesn't break (it flexes in a behavior closer - not equal but closer - to ABS).
Regards
Pedro.
Last edited by PedroR on Wed Sep 04, 2013 4:29 pm, edited 2 times in total.
by mantrid
Thu Jul 11, 2013 4:35 pm
Pedro
The more you talk the more I learn ...
I've just noticed a report on BBC teletext (yeah some of us still use it - bad though its become) about a carolina university 3D printing with gallium and indium - the claim is potential for flexible circuits. Apparently the material is liquid but forms a skin when exposed to the air.
(yes I know that flexible circuits can already be done)
So now I've seen metals, plastics, chocolate, liquid-wood, I wonder what's next? Industrial 3D printers doing glass maybe? Or treacle or or .... print your own jelly babies... yum.
The more you talk the more I learn ...
I've just noticed a report on BBC teletext (yeah some of us still use it - bad though its become) about a carolina university 3D printing with gallium and indium - the claim is potential for flexible circuits. Apparently the material is liquid but forms a skin when exposed to the air.
(yes I know that flexible circuits can already be done)
So now I've seen metals, plastics, chocolate, liquid-wood, I wonder what's next? Industrial 3D printers doing glass maybe? Or treacle or or .... print your own jelly babies... yum.
by PedroR
Thu Jul 11, 2013 4:39 pm
Thanks and ... LOL on your punch line
now that 1.75mm filament extruders are pretty reliable people have been experimenting with different materials.
There is for example Wood with resin: http://hackaday.com/2012/09/21/3d-print ... e-of-wood/
Nylon: http://richrap.blogspot.pt/2013/04/3d-p ... nt-in.html
Nylon is a material that seems to be growing in popularity among the "hacker" community of 3D printer operators.
I don't know much about printing with Nylon except that it's expensive and that you need a heated build plate from what I've read to help with deformation while cooling (similar side effect to ABS).
Regards
Pedro.
now that 1.75mm filament extruders are pretty reliable people have been experimenting with different materials.
There is for example Wood with resin: http://hackaday.com/2012/09/21/3d-print ... e-of-wood/
Nylon: http://richrap.blogspot.pt/2013/04/3d-p ... nt-in.html
Nylon is a material that seems to be growing in popularity among the "hacker" community of 3D printer operators.
I don't know much about printing with Nylon except that it's expensive and that you need a heated build plate from what I've read to help with deformation while cooling (similar side effect to ABS).
Regards
Pedro.
Re: Printing with PLA vs ABS demystified
by PeterGrant
Thu Mar 27, 2014 3:03 am
So far, I have no issues with my plastic ABS filament. Printing with my 3d2print’s ABS filament is fairly straight forward although compared with PLA, a heated print platform is required. Just a piece of advice, printing on a heat bed at approximately 80° to 100 °C will prevent ABS filament warping. Please be guided guys.
Re: Printing with PLA vs ABS demystified
by PrinterNinja
Fri May 30, 2014 6:05 pm
What a great informational post Pedro. I think PLA is slowly going to outpace ABS for usefulness simply because it prints so much easier and it doesn't stink so much when you print it.
Re: Printing with PLA vs ABS demystified
by edwardjennings66
Thu Jun 19, 2014 2:24 pm
Thanks for the share. Also, take a peek at this www.3d2print.net/shop/blog/2014/03/13/a ... omparison/. It discusses the comparison between ABS and PLA. This helped me decide what filament to use.