Two Extruder PETG Problems

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JamesW
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Joined: Tue Jul 03, 2018 4:54 pm

Two Extruder PETG Problems

Postby JamesW » Fri Aug 03, 2018 2:27 am

I am trying to print a two color benchy with Hatchbox PETG and can't seem to stop the oozing. I lowered the temperature to 230 but then I got a filament jam. When I removed the filament it had expanded to about 2.05 mm so I don't know if the filament caused the jam or the subsequent heat expanded the filament.
So now I have increased retraction to 2.00 added a z-hop and have a wipe tower and ooze guard both. I have the extruders set to 237 now. this (please notice the boogering) is what I have:
Attachments
20180802_212205.jpg

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Vicky@Raise3D
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Re: Two Extruder PETG Problems

Postby Vicky@Raise3D » Fri Aug 03, 2018 5:01 pm

230C is too low for PETG. Higher than 240C, or 245-255C will be better.
Normally PETG will ooze a little bit more than other filament, especially when the spool with high moisture.

JamesW
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Re: Two Extruder PETG Problems

Postby JamesW » Fri Aug 03, 2018 8:48 pm

You might think that 230 is too low for PETG but that is what both filaments have as their lower temperature. As you can see in the photo I have significant oozing and stringing at that temperature. At the point when it clogged, the print was actually solid so I am not sure what about 230 was too low. It was the filament that jammed and it jammed not at the bottom but higher somewhere with one to two inchest of filament unmelted. I could see on the filament where it was too thick. But then again, maybe too low a heat was slowing the filament so that it had time to clog at a higher point....but if that's the case then I will never be able to PETG with two extruders because I always have to use a higher temperature to avoid a clog and it always oozing even at a lower temperature.
So...anyway, this is the result with temperature 237 and two extruders with PETG. I should also mention that both spools were RIGHT out of their bags. Also - isn't PETG hydrophobic? (edit - Yeah, it's not but still not what's wrong here.) It should not have been a problem here. All doors closed on the unit.
Attachments
20180803_070705.jpg
Last edited by JamesW on Fri Aug 03, 2018 8:57 pm, edited 1 time in total.

JamesW
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Joined: Tue Jul 03, 2018 4:54 pm

Re: Two Extruder PETG Problems

Postby JamesW » Fri Aug 03, 2018 8:55 pm

On the plus side....no clog this time.
the print base looked and felt the same at 230 and 237. No appreciable difference in it's cohesion.
Oh - PETG adheres to the the Builtak wonderfully and is easy to remove with a spatula.
I am about ready to give up on two extruder printing with PETG for right now. I can do it with PLA and it looks pretty nice. I will just watch the boards until someone comes up with a solution or a suggestion.

Shelton
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Re: Two Extruder PETG Problems

Postby Shelton » Fri Aug 03, 2018 9:45 pm

Try to dry your PETG spool first in the oven. Second, set it to 240 C. All settings from factory work perfect for me. Door closed lid open.

Try to use default retraction. I was going too high and I was getting first beware by clicking sound from gears than nice jam after that. So, I will try to keep very near factory settings... and for me, this works perfectly. I prefer to print with PETG than with PLA.

And the last supports, try to place them on the raft with support base layer also.

JamesW
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Re: Two Extruder PETG Problems

Postby JamesW » Fri Aug 03, 2018 10:02 pm

I appreciate your response but I don't see you saying two extruders work with PETG for you.
With either exruder I can print things with PETG that look nice - even at standard settings with no temperature change.
But with dual extruders I get poor results. See my pictures. Oozing/Stringing.

Again, both rolls of PETG, were just out of sealed bags from the company. I do not see pitting or hear hissing when it's used. There is no sign of moisture from either spool and again, I have used them both to print single extruder prints without problem. Since the problem is oozing from one extruder when the other is printing - this is what is expected.

Have you printed with both extruders at the same time on a PRO2?

Shelton
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Re: Two Extruder PETG Problems

Postby Shelton » Fri Aug 03, 2018 10:05 pm

Yes but not with PETG... PLA.

JamesW
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Re: Two Extruder PETG Problems

Postby JamesW » Fri Aug 03, 2018 10:09 pm

It works nicely with two extruders and PLA. I think my third print was a two color benchy with the original colors - red and white.

Well, drying the PETG rolls will force me to break open another roll of something else.
Thanks for the advice.

Alex M.
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Re: Two Extruder PETG Problems

Postby Alex M. » Fri Aug 03, 2018 11:36 pm

With all that oozing & stringing I would think that you are running two hot and not too cold. Based on your latest comments that it works fine for you when you print with a single extruder but fails with dual extruders and clogs higher up, I wonder if you are having a heat creep issue or something similar when using dual extruders.

I don't have a Pro2 but have followed several post and wonder if these have anything to do with it:
viewtopic.php?f=4&t=9575#p33254
viewtopic.php?f=18&t=9848#p33825

Don't know if this is realated or not but the Pro2s seem to be tempermental about filaments and the temperature they run at. Wondering if the fewer & small cooling fins on the throat tube of the Pro2 are causing your issue when running dual extruders due to the extra heat.

JamesW
Posts: 31
Joined: Tue Jul 03, 2018 4:54 pm

Re: Two Extruder PETG Problems

Postby JamesW » Sat Aug 04, 2018 12:37 am

Sorry; I must not be communicating effectively. Thank you for the replies.

I have only tried PETG with the single extruders at factory PRO2 settings. They work fine at 250. There is oozing but because the single extruder is used continuously it doesn't matter. I imagine if I paused the printing for some reason I would have the same kind of issues with a single extruder I have with dual extrusion.

With two extruders I have tried at 250 (factory), 245, 240, 237, and 230. I get oozing/stringing at all settings. It's definitely worse at at higher temperatures. Even at 230 I was getting the problem but about 1/4 of the way through the print I had a jam. I shouldn't call it a clog because the filament wasn't at the melting area yet - it was about halfway down the machinery about 1.5 to 2 inches above the hot end. It *could* be because the filament expanded it could have been a factory defect in the filament - it could have been both. I don't know. It was suggested it might have been moisture but I had oozing and stringing without any hissing or pitting/splattering. Both spools were new and directly from bags. Still to be sure I am drying the spools right now. I will try them again tomorrow.

I don't understand Vicky's comment about the temperature (230) being too low since the filament roll is labeled with a extruder temperature of 220 to 250. She also commented positively on another person's post about using Matterhacker's PETG at 220. I think she must have thought I was using a different material.

I am interested in knowing if anyone has had success with DUAL extruder prints with PETG. If so, what settings were you using. I have had success in printing PLA with two extruders and PETG with single extruder.

I am sorry if my previous posts confused anyone. It's been a long week.

(Oh - and when I was removing the spools I noted that the black one wasn't HATCHBOX - it was PRILINE. I apologize for the mistake. It had the same specifications as the HATCHBOX in terms of temperature and was performing fine with single extrusion.)

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carver0510
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Re: Two Extruder PETG Problems

Postby carver0510 » Wed Aug 08, 2018 10:23 am

Hi,

I have also tried to print PETG with both nozzles (I am using PETG from Extrudr) but with no succes.

Printing it with a single nozzle I had good results at 220°C nozzle temperature and 75°C for the bed. The problem I identified when printing with dual nozzle is following:

For example the printer is printing with the left nozzle, the right nozzle is lifted. But there is still some filament coming out of the right nozzle, although it shouldn't. So when the Pro2 is changing to the right nozzle, there is a lot of hardened filament in front of the right nozzle which make it impossible to stick the heated filament to the layers.

There is always running some PETG out of the lifted nozzle. I have tried different retraction amounts ... up to 50mm ... but this clogged my nozzle.
normaly you retract your filmanet to a cooler area of the hotend and prevent it from melting. But it seems that the filament is still melting and it is dripping out of the nozzle.

But it also looks like, if the step motors of the feeder of the lifted nozzle is still (but very very slow) feeding the filament towards the nozzle. I haven't confirmed it yet ... but it looks similar to it.

Maybe a problem could be, that the hotend have not the good cooling of the N2 series so it is to hot. There are less cooling fins at the hotend of the Pro 2 than of the N2. Which means there is much less area to give off the heat.

Maybe a better cooling of the hotend can solve the Problem:

@Vicky@Raise3D can you confirm this?

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Vicky@Raise3D
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Re: Two Extruder PETG Problems

Postby Vicky@Raise3D » Thu Aug 09, 2018 11:40 pm

Factors affect strings of PETG normally are the following three:
1. Wrong temperature
2. Wrong retraction
3. Humidity

If all three cannot help the result, you may need to consider try some different brands.

JamesW
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Joined: Tue Jul 03, 2018 4:54 pm

Re: Two Extruder PETG Problems

Postby JamesW » Fri Aug 10, 2018 12:09 am

I am sorry that I have not got back to this thread sooner. I wanted to include some pictures.

I was having trouble with constant extrusion from 230 degrees to 250 degree. The PETG was rated for temperatures from 220 to 250 but no matter what I did both extruders leaked and oozed.
I am SO glad that I didn't just continue playing with the temperature and instead took the good advice (thanks SHELTON) to dry the PETG. Even though I was convinced that because I had new filament -just out of the box- that it would be dry; This was not the case. I dried the filament in a homemade dryer made from a 5 gallon bucket on top of a food dehydrator for a few hours. After drying I have only a little oozing. The result print still isn't great but I was able to print a benchy and the ooze shield didn't look a a bad perm (hairdo). It looked clean.
I need to play with temperature and retraction more now that the oozing has stopped to make the print look better.
Attachments
20180809_192451.jpg
The Benchy - not great
20180805_201552.jpg
Less oozing... am I right?

Shelton
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Joined: Thu Jul 12, 2018 8:34 pm

Re: Two Extruder PETG Problems

Postby Shelton » Fri Aug 10, 2018 6:37 am

Good to hear mate. I need to buy a cheap heater also... or even little electric oven ;)

JamesW
Posts: 31
Joined: Tue Jul 03, 2018 4:54 pm

Re: Two Extruder PETG Problems

Postby JamesW » Fri Aug 10, 2018 8:25 pm

I just got a $35 food dehydrator and an (upside-down) 5 gallon bucket from Home Depot to put on top of it.
I fully intend on cutting a hole in the top so that I have an actual flow of air from bottom to top and mount some cheapo $2 digital temperature/humidity sensors in the sides at some point but hey - it obviously worked. I don't think the temperature ever got as hot as it was *set* to on the dial but then again every web site had a different time/temperature anyway.


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