Print Quality issues (pictures)

[Sebastian Finke]

I use rafts quite a lot.

BUT

I use a HIPS raft while the actual part is in ABS. I do this so that a) the parts is exactly the height I want it to be and b) to get a consistent 'printed' finish on every surface (as opposed to one face being very smooth).

[Sebastian Finke]

Really just a waste of time and filament.

I have a slightly different philosophy here:

All that matters is the part.

How I get it is irrelevant. If the part is a masterpiece then every step it took to get there was worth it.

[Sebastian Finke]

it really is interesting. Pretty much everyone at the tct show was using pla and most when asked just thought abs was an awful out of date material and wouldn't use it.

Lets get real here for a second: People at shows want to sell printers. They're not gonna show you all the effort it takes to fine-tune their machines. That's why the same questions get asked here day in and day out.

Furthermore, they reason they use PLA at the shows is because they run their printer without enclosures. It looks so much friendlier without the enclosure, when the punters can see the inner workings close-up. That's why the exhibitors always print things like vases and bowls, never anything complex with overhangs, etc. Sure they'll may have other items on display but not actually printing.

So have you enclosed your creator sebastian ?

Yup. Made my own out stuff I had lying about. Took like half an hour.

But for me the warpage, smell and reliance on acetone just massively outweigh any potential benefits.

Warpage - a non-issue
Smell - open a window
Acetone - I use maybe 100ml every 2 months

Compared to PLA, ABS is a dream.

PLA is bio-degradable. While that's normally a good thing, bear in mind that no part printed in PLA will have the longevity of ABS. Anecdotal evidence suggests that structural disintegration starts after about 6 months (cracking, delamination).

PLA is very hard, resulting in a brittle part. I have printed a whole range of snap-together electric cases that wouldn't have been possible in PLA is the snapping lugs would simply have snapped off. Saying PLA is stronger than ABS due to its hardness is misleading; it would be the same as saying that glass is stronger than steel.

PLA's hardness also makes it more of a chore to post-process eg. sanding.

As far as smell goes... really? Its like saying don't drive a car because exhaust fumes smell bad. I don't recognize a bad smell and feel my life is in danger, open a window.

Acetone usage... here you complain about the smell. And hairspray doesn't smell? The odd time I use PLA I use sugar water for adhesion, take the same amount of time to mix as ABS slurry.

From a purely mechanical point of view ABS is still the standard for prototyping. That's based on actual industry experience (remember, I am an engineer irl). PLA is for trinkets and mucking about at home.

[curious aardvark]

PLA doesn't have the strength that I need. ABS does

then you are using the wrong pla.

Look the abs versus pla argument is completely redundant.

The term 'pla' now encompasses hundreds of different materials - with different formulas and manufacturing processes.
So 'pla' IS stronger, more flexible, tougher etc than abs - simply because there are so many different types to choose from.
Abs comes in abs plus - which shrinks slightly less and is a little tougher than normal abs, but very little else.

Pla is where the real material innovation is at.
So it's a non-argument, pla can be had in verisons that are more flexible, stronger, more durable and with much higher temperature glass points. Nobody is putting much effort into improving abs - so while it's a decent material - albeit with a lot of flaws. It is yesterdays filament.
It's a plastic that was designed for injection moulding - why it shrinks.
Pla has been and is being designed for 3d printing.

Yes abs works for you sebastian - you've put a lot of time and effort into making sure it does.
But the world of pla based materials is for everybody and every printer and from graphene infused filaments to ninjaflex beating flexible filaments the term 'pla' encompasses just about every type and characteristic you could possibly want.
And we're still in the dawn of 3d printing materials.

Every week someone else brings out a new type of pla with different and better properties than the available abs.
Pla based materials is where the industry is spending it's development money. Abs isn't quite dead yet - but it's on the way out.

[Sebastian Finke]

PLA just doesn't come close to ABS in terms of industrial applications. As mentioned it hardness and its bio-degradability are key factors, as are its melting and glass points. If these mechanical issues were already addressed we'd be seeing more of it in real-everyday applications. As it is PLA is used in one-time-use food packaging and camping-ware.

Maybe one day it will get there. Maybe. I reckon it will, as everyone wants to go green. However until its mechanical shortcomings are addressed it won't happen.

Polylactic Acid ≠ Acrylonitrile Butadiene Styrene.

[curious aardvark]

If these mechanical issues were already addressed we'd be seeing more of it in real-everyday applications.

why ?

These are materials specifically created for use in 3d printers. Not undustrial factory usage plastics.
Compared to bog standard abs - they're also not cheap.
But that's not the point, the point is that pla is where the future of 3d printing filament is and many of the great new materials are available now.

You're really not seeing this at all are you ?

[Sebastian Finke]

Isn't that exactly what I've been saying? My 3D printing revolves around engineering related parts. These things are working prototypes and need to be able to withstand physical demands. PLA is not in this league. For home use i.e trinkets, vases, horses, whatever... that's fine. Go nuts with PLA.

None of the Big Daddy's in 3D printing bother with PLA. They use materials like ABS, PPS, PA, PMMA, PC.

[Sebastian Finke]

I am not anti-PLA, btw. It has its place. But to state that PLA is better than ABS simply because it doesn't suffer from shrinkage and smells like popcorn is misleading.

[jfkansas]

3DXtech is doing good work with special ABS mix filaments. Run of the mill ABS for injection molding isn't quite the same as ABS used for extrusion so there is plenty going on in the world of ABS tech. I also use ABS or ABS/Carbon Fiber for all structural components. Good stuff. PLA has its place though, not sure how Wood fill would get along with ABS, probably why you only see it in PLA.

[catalyst]

3DXtech is doing good work with special ABS mix filaments. Run of the mill ABS for injection molding isn't quite the same as ABS used for extrusion so there is plenty going on in the world of ABS tech. I also use ABS or ABS/Carbon Fiber for all structural components. Good stuff. PLA has its place though, not sure how Wood fill would get along with ABS, probably why you only see it in PLA.

I am also printing prototypes. For the objects i am printing, i am able to put some pretty intense force on my abs prints where the pla was failing under the same force. Pla has its use, but not for what i am doing.

I also prefer to print without a raft, but i also do not use an acetone smoothing process, print at .1 layer height, and want one side smooth. The only thing i dislike, is that i generally find myself running a file or sand paper along the prrimeter of the completed print to remove the edge where it adhered to the bed.