Any reason you are recommending PLA instead of PETG?

From my experience PLA is just easier to print - prints are less likely to fail and more consistent.

Also due to lower nozzle and bed temperatures, prints start faster so you can check the first layer sooner before you let the printer do its thing.

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Fomite 4 hours ago | parent | prev | next [-]

For some applications, PLA is a little more rigid. It will then fail in a spectacular fashion, but "I need you not to bend" is something PETG doesn't always perform the best for.

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IgorPartola 12 hours ago | parent | prev | next [-]

I still get worse finish quality with PETG (stringing and globbing) and these PLA+ type materials just end up being as good for me while being easier to print. PLA also prints a bit faster.

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jacquesm 12 hours ago | parent [-]

This is not my experience. PETG should be utterly problem free, super fast to print and has a much lower fraction of failed prints due to various adhesion issues. The big trick is to make sure the filament is dry, if it is not you will be in for a world of trouble. But properly used prints will last much longer, and are mechanically (much) stronger. On top of all that we can buy PETG in bulk for about a third of the price of PLA.

For functional parts I would not use anything else until there is a really good reason (such as high temperature stability or more strength for a given weight or cross section). I've gone through multiple tons of the stuff now (3500 Kg in total or so) on 85 printers (Bambu's (43), Creality (22) K1s and Prusas (20)), consistency between batches is very good though from brand to brand there can be some notable differences.

If you have stringing and globbing problems with PETG my first guess would be that the filament profile that you are using is subtly off for that particular brand of PETG and/or that the filament wasn't dry.

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noo_u 11 hours ago | parent [-]

Calling PETG "utterly problem free" is quite a stretch lol. PLA is pretty objectively much easier to print than PETG, and perhaps than all the popular filament types out there, especially if you are trying to print anything where precision/detail matters. .

PETG is just oozier and stickier by default, so stringiness is almost guaranteed to happen, bridging at a greater risk of failure, etc. It is tougher, so unless you have a printer that can use multiple filaments on the same print, removing supports is more difficult.

Can you reduce these factors by tuning your 3D printer - yes, a bit. But that's not "utterly problem free".

PLA is the plug and play of the 3D printing world right now.

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jacquesm 10 hours ago | parent [-]

When you print objects with 10's of printers 'tuning your 3D printer' is no longer an option other than to tune it to be 'in spec' You can only tune your designs and the profile for your filament and for a particular model of printer but then all of those have to be close to identical. As soon as you start tweaking your design or filament profile to offset possible issues with the printer you've lost reproducibility.

Incidentally, a lot of the stuff on thingiverse and other similar sites suffers from those kind of issues. They are tuned for PLA on a particular printer without realizing it.

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noo_u 5 hours ago | parent [-]

The real question is - did you buy 10s of printers because you needed them for the business, or did you start the business to buy 10s of printers :P

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jacquesm an hour ago | parent [-]

I bought one, to try out some ideas, then it sat on the shelf for about a year, then suddenly there were five and so on.

	▲	noo_u 15 minutes ago \| parent [-]
		I have a few shelves that got populated with things in a very similar fashion...

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the__alchemist 11 hours ago | parent | prev | next [-]

PETG is, for me, always stringy. And I don't want to breath ABS fumes.

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zihotki 12 hours ago | parent | prev | next [-]

any reason to use PETG instead of PLA? PLA is plant based, in theory bio-degradable, while PETG is produced from crude oil.

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brovonov 12 hours ago | parent | next [-]

That is mostly true, PLA is ONLY biodegradable in a facility that can handle that. Your run of the mill recycling center in your city probably can't or won't take your PLA prints.

	▲	gambiting 10 hours ago \| parent [-]
		And then only if it's pure PLA with no additives. Which most PLA has to improve speed of printing or strength or some other property. In practice, I'd wager that 90% of commercially available PLA fillament is not actually biodegradable.

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dgroshev 11 hours ago | parent | prev [-]

Less creep, slightly better at absorbing shocks without breaking, better failure behaviour (PLA can suddenly shatter leaving sharp edges, PETG tends to deform elastically first).

	▲	Fomite 4 hours ago \| parent [-]
		Note that "deform elastically" is not necessarily a desirable failure state if it happens earlier than shattering.

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dangus 12 hours ago | parent | prev [-]

Not the person you’re replying to, but I can see the appeal of PLA. It has more color options and prints way easier.

I personally run all PETG because it is ultimately better material post-print, and once you understand how to print with it, it’s not really much harder to deal with.

The day I discovered that I should just run my dryer with the PETG inside while printing was revolutionary. Of course, that requires you own a dryer that allows the filament to print while it’s inside.

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IgorPartola 12 hours ago | parent [-]

I wish I knew how to dial in PETG fully. It prints fine for me but I still get globbing and stringing so the surface finish just isn’t that amazing.

	▲	Ccecil 2 hours ago \| parent \| next [-]
		In my case PETG had issues until I realized that on my machine it needs to go slower. I can print PLA at 100mm/s with .25mm layers...but PETG I don't go much over 65mm/s give the same line width/layer height. Since getting things dialed in I switched to primarily printing PETG. Although, I have no issue printing PLA, PETG or ABS when needed.
	▲	dangus 10 hours ago \| parent \| prev [-]
		That's definitely still where I see the appeal of PLA, and once I get through the too much bulk PETG that I own I may mix up my future purchases to have more PLA where I don't need load strength and won't have issues with high temperature usage. I am getting reasonably consistent prints but they aren't perfect. The long version of my tips for using PETG are: - A Bambu Lab printer doesn't hurt since it's so nicely calibrated and idiot-proof - Clean the build plate with dish soap and dry fully. I haven't found any need for glue stick on a textured plate. - Using a filament that has a profile available from the manufacturer for Bambu lab printers - Printing with the filament in the dryer with the dryer running during printing