UK - Filament sources

FryingSaucer said:

I just put in an order for PETG from real-filament, but you've persuaded me to order a spool of midnight silver from 3dqf as well.

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As it happens I also have some (white) PETG from Real Filament. They vary a lot between manufacturers, so perhaps @The Hat's PETG is harder to work with, but I've had reasonable success with mine. It does take some experimentation to get good results, and my settings might not work for you (thermistor accuracy can vary between printers for example). I use 230C nozzle, 80C bed, and print slower than for PLA, around 40mm/sec. The main problem is stopping the filament from sticking to the nozzle. You then get burnt blobs deposited at random around the print. Try to avoid the nozzle tip dragging through the first layer. You might need to raise the z=0 height slightly above normal (it doesn't need as much "squish" as PLA). Some people cover their heater block with a silicone cover to prevent build up. Sticks well to plain, clean glass, a thin layer of dried Pritt stick, or a dilute PVA coating. Beware that it can stick too well - I've heard reports of PETG taking out chunks of glass from the bed as it cools, though I haven't experienced this myself (yet...). Using an adhesive layer should protect against this.

Good luck and please report back how you get on with it.

I'm still learning about Cura slicer, but there is a setting called Z hop which might help with with the nozzle dragging but I'm not sure what each setting actually does yet

ninj said:

As it happens I also have some (white) PETG from Real Filament. They vary a lot between manufacturers, so perhaps @The Hat's PETG is harder to work with, but I've had reasonable success with mine. It does take some experimentation to get good results, and my settings might not work for you (thermistor accuracy can vary between printers for example). I use 230C nozzle, 80C bed, and print slower than for PLA, around 40mm/sec. The main problem is stopping the filament from sticking to the nozzle. You then get burnt blobs deposited at random around the print. Try to avoid the nozzle tip dragging through the first layer. You might need to raise the z=0 height slightly above normal (it doesn't need as much "squish" as PLA). Some people cover their heater block with a silicone cover to prevent build up. Sticks well to plain, clean glass, a thin layer of dried Pritt stick, or a dilute PVA coating. Beware that it can stick too well - I've heard reports of PETG taking out chunks of glass from the bed as it cools, though I haven't experienced this myself (yet...). Using an adhesive layer should protect against this.

Good luck and please report back how you get on with it.

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Thanks. Maybe I should have a spare piece of glass before I start removing chunks of it

The first print will be better clips for the glass to the bed. These PLA ones do not retain their tight fitting on my heated bed at 50°C, and would be useless at higher temperatures. I'm also hoping the PETG will be more springy. If I can't print something simple like this in PETG, I won't be able to print anything.

I'll report how it goes.

That should be a straightforward print. PETG is not so good at certain things, such as bridging, but I don't think your part has any. The main thing is to get the first layer right - get the temperature and z-height right and stand by with tweezers to remove any stray oozing off the nozzle or bed. Also, print the first layer really slowly - maybe 15mm/s. A brim might help if you have any adhesion problems, but isn't usually required. PETG also rewards careful retraction tuning. I'm currently experimenting with pressure advance in my firmware settings (RepRapFirmware) to reduce blobbing - I think this may now be an option in some other firmware as well (I think recent versions of Marlin may have it).

Another thing to be aware of with PETG is that the filament absorbs moisture more readily than PLA. Best to keep it protected in a sealed bag with desiccant. If it absorbs atmospheric water it will print really badly and then needs to be dried out in something like a food desiccator (there are various methods described online).

@The Hat - just a thought, but it might be worth drying your PETG filament to see if that gives better results. I've even heard of cases where PETG arrived from the factory with too much moisture in it. I guess the humidity levels in Ireland are fairly high this time of year, which doesn't help.

ninj said:

That should be a straightforward print.

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You were correct. I used the settings you suggested, and it worked first time.

I used a glass bed, no adhesive or anything, no brim. No problem with adhesion, when the print finished, I removed the glass from the bed, it cooled down quickly, and the parts came off easily with a slight twist. I may have to find another use for two cans of hairspray

Next print will be equally simple. A long hollow rod and a connecting rod to repair a shopping bag handle. I tried this with PLA, but it wouldn't take the weight of a full bag. I think PETG should be strong enough.

I’m going to wait till the weather picks up and the humidity levels off to 70%, then I’ll have another go at the PETG, it reacted the same as ABS, it stuck down and stayed in position but as the print proceeded the head was extruding less and less filament and eventually stopped altogether.

Once that happens there is no alternative but to take the hot-end apart and remove all the petrified filament, you may need a good heat source because the junk inside won’t come out easy otherwise, I now use a Bunsen burner.

I have my ABS and PETG reels in the house keeping them nice and warm and will keep them there till I decide to try them again, the 3D printers are a lot easier to trouble shoot and solve a print problem with, but they can have their own version of ink starvation.

I washed and cleaned my glass bed before Christmas (Warm soapy water) and had a hell of a time getting anything to stick to it again, but eventually I got enough new spray laid down, and it started to work properly again, so what worked yesterday may not necessary work today, I reckoned I got to complaisant.

FryingSaucer said:

Next print will be equally simple. A long hollow rod and a connecting rod to repair a shopping bag handle. I tried this with PLA, but it wouldn't take the weight of a full bag. I think PETG should be strong enough.

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Could it be your fill density % that’s giving you the lack of strength, or try enclosing the rod in a hand grip...

The Hat said:

I’m going to wait till the weather picks up and the humidity levels off to 70%

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Must be due to all the Guinness that's around over the holiday season One thing I do is keep spools of filament in a vacuum sealed bags with some desiccant if I'm not using them - but then I'm not frequently changing filaments.

I'm not surprised you're giving up on PETG for the moment if you have to take a Bunsen burner to the hotend. I'm surprised PETG has worked reasonably OK for me so far. It can be difficult to get the first layer down, but once it's down the print sticks OK and comes off easily, and I've not had any nozzle clogs. So far I've just used the same settings as for PLA apart from the different temperatures. However, I've always used low print speeds, 30mm/s and initial layer speed of 15mm/s and maybe that's helping with the PETG.

But at the moment I'm having difficulty printing a 9mm diameter 200mm long rod. Once Z > about 150mm, the rod keels over. I guess the torque on the bed has got too much. I've tried brims and rafts without success. I could try adhesive on the glass, but instead I'm just printing a large cone at the bottom of the rod, and I'll saw the rod off when it's printed. That's got to work.

FryingSaucer said:

One thing I do is keep spools of filament in a vacuum sealed bags with some desiccant if I'm not using them - but then I'm not frequently changing filaments.

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Maybe that’s my problem, I’ve got 5 soon to be six rolls out on rollers so I can easily swap to which ever colour takes my fancy, I like to have each roll ready to go at a moment’s notice, it’s 10 Degrees here tonight but with a lot of moisture in the air...

I'm not surprised you're giving up on PETG for the moment if you have to take a Bunsen burner to the hotend. I'm surprised PETG has worked reasonably OK for me so far

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when you have to do any work on the hot-end, it has stay hot so you can clean it and once you take it apart you lose that option of using the heat block to that job.

However, I've always used low print speeds, 30mm/s and initial layer speed of 15mm/s and maybe that's helping with the PETG.
But at the moment I'm having difficulty printing a 9mm diameter 200mm long rod. Once Z > about 150mm, the rod keels over. I guess the torque on the bed has got too much. I've tried brims and rafts without success

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If you’re having difficulties with the long rod standing still, why not lay it flat, that’s the way I do most of my cylinders and pipes, I can call low speed 150% and low, low speed at 100%, I’ll try PETG at 50% when next I use it, have you tried increasing support to everywhere...

The Hat said:

Maybe that’s my problem, I’ve got 5 soon to be six rolls out on rollers so I can easily swap to which ever colour takes my fancy, I like to have each roll ready to go at a moment’s notice, it’s 10 Degrees here tonight but with a lot of moisture in the air....

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When filament absorbs water, it expands in thickness and weakens, causing problems in the extruder and hot-end. Dry the filament or replace it, and store it over dessicant. You'll like the result.

The Hat said:

when you have to do any work on the hot-end, it has stay hot so you can clean it and once you take it apart you lose that option of using the heat block to that job..

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Do you use the hot-pull/cold-pull method of unclogging the hotend? It appears to be relative quick and less likely to ruin a nozzle.

https://ultimaker.com/en/resources/23132-clogged-print-core

https://www.youtube.com/watch?v=g8uvh6kvr54

Happy new year.

The Hat said:

Maybe that’s my problem, I’ve got 5 soon to be six rolls out on rollers so I can easily swap to which ever colour takes my fancy, I like to have each roll ready to go at a moment’s notice, it’s 10 Degrees here tonight but with a lot of moisture in the air...

when you have to do any work on the hot-end, it has stay hot so you can clean it and once you take it apart you lose that option of using the heat block to that job.

If you’re having difficulties with the long rod standing still, why not lay it flat, that’s the way I do most of my cylinders and pipes, I can call low speed 150% and low, low speed at 100%, I’ll try PETG at 50% when next I use it, have you tried increasing support to everywhere...

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I've not been using my printer for 18 months. The printer has been in a closed cupboard in the garage. The filament I was using was inside the house in a vacuum sealed bag. I've had to print something for a project I'm working on. I resurrected the printer and the filament.

The vacuum in the filament bag was as I stored it. I switched on the printer, connected the PETG spool I had been using, and everything worked as before. No bubbling in the filament to imply it had absorbed any moisture.

I'm sure I get less rain than @The Hat does, but over 18 months there's been some pretty wet weather here. I didn't expect the filament to be in the same pristine condition as I stored it. The vacuum sealing method has worked really well for me. I use PETG filament from Real Filament https://www.amazon.co.uk/Real-Filament-8719128327235-Spool-Transparent/dp/B01MCYYCLM.