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How best to switch from PETG back to PLA?  

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dimprov
(@dimprov)
Noble Member
How best to switch from PETG back to PLA?

Going from PLA to PETG was easy, because the melt temperature for PETG is higher. i.e. the risidual PLA flowed out of the nozzle one the PETG was inserted.

However, going the other way, how do I ensure all of the PETG is gone so that it doesn't create a clog?

Posted : 19/05/2018 4:30 pm
stoofer
(@stoofer)
Estimable Member
Re: How best to switch from PETG back to PLA?

Should be fine, I switch all the time and the PLA hot end temps have no problem pushing out what remains of the PET when swapping filament.

Posted : 19/05/2018 4:57 pm
Pintie
(@pintie)
Eminent Member
Re: How best to switch from PETG back to PLA?

same here. 200° is enough to change...
never had an issue...

Posted : 19/05/2018 5:37 pm
bill.f5
(@bill-f5)
Trusted Member
Re: How best to switch from PETG back to PLA?

When changing from black PETG to Woodfill PLA I had some black strips appears suprisingly a ways into the print. I had purged twice on the load to make sure. Because of that I now do the filament switch at the PETG temps and then lower it to the PLA temp for printing.

Proud owner of a Mk3 that is producing very nice prints. There is room for improvement as I learn more about it, but so far I am very happy....
Posted : 19/05/2018 6:37 pm
GertL
(@gertl)
Reputable Member
Re: How best to switch from PETG back to PLA?

I have eSUN cleaning filament. It has a very broad temperature range, 160 to 280C if i remember correctly. When i swap filament i run this cleaning filament through at 250C. It takes everything with it out.

---
Gert...
Posted : 19/05/2018 7:04 pm
dimprov
(@dimprov)
Noble Member
Topic starter answered:
Re: How best to switch from PETG back to PLA?


I have eSUN cleaning filament. It has a very broad temperature range, 160 to 280C if i remember correctly. When i swap filament i run this cleaning filament through at 250C. It takes everything with it out.

Thanks for the suggestion because, sure enough, I immediately got a jam.

Posted : 20/05/2018 2:07 am
daniel.d30
(@daniel-d30)
Eminent Member
Re: How best to switch from PETG back to PLA?

I use the 3DXTech PETG (love it), it prints at about 270degrees. Changing from it to PLA is a process because I was getting jams constantly. Now, I use the eSun cleaning filament at 280, and constantly extrude while slowly stepping the temp down to the PLA temp. It usually works, but I really don't think it is the best method as it is not 100% effective. The longer I extrude the cleaning filament at the higher temps, the better my chances are.. Many of you seem to be able to change without having trouble.. it must be due to using a PETG that is not required to be printed at such high temps. If anyone has a better way to make the change from a HT PETG I am all ears. Any other suggestions?

Posted : 20/05/2018 6:54 pm
bobstro liked
Joe Prints
(@joe-prints)
Estimable Member
Re: How best to switch from PETG back to PLA?

I use alot of 3DXTech's MaxG PETG, I run it at 240C. I just run the PLA through at the same temp of the PETG until it looks good coming out

Anything can be made better
https://www.myminifactory.com/users/Joe%20Prints...
Posted : 20/05/2018 7:08 pm
eric.d14
(@eric-d14)
Eminent Member
Re: How best to switch from PETG back to PLA?

Consider doing a cold pull with the eSun cleaning filament after manually extruding till it looks clear. The cleaning filament is really "sticky" and will pull up a load of old plastic from to the walls of the nozzle.

Posted : 20/05/2018 9:48 pm
bobstro liked
motocoder
(@motocoder)
Trusted Member
Re: How best to switch from PETG back to PLA?

I use the eSun cleaning filament as well. In addition to extruding a bunch of that, I also do at least one "cold pull".

Posted : 21/05/2018 11:17 pm
bobstro liked
krikru
(@krikru)
New Member
Re: How best to switch from PETG back to PLA?

Anyone who does a cold pull with the old filament before changing to a new one, in order to require less purging?

Posted : 21/07/2021 9:58 pm
jsw
 jsw
(@jsw)
Noble Member
title here

I switch between PLA and PETg (and ABS) all the time.

When I change filament I'll usually heat the nozzle to the temperature of the higher temperature filament for the unload and the load.  Then, if I'm going to a lower temp filament, set the preheat to that of the newly loaded filament.

I'll always do at least two, usually three, sometimes more of those 'Is the new filament extruding correctly' cycles when going from one species of filament to another.  I'll also add a few cycles if going from a metallic filament to a nonmetallic.

Posted : 22/07/2021 4:21 am
bobstro
(@bobstro)
Illustrious Member
Cleaning filament at 265C and a cold pull ensures consistently clean hotend and nozzle

Going from cooler (PLA) to hotter (PETG, ABS) temperatures is not a problem since any leftover filament will simply melt out. Going from hotter (PETG, ABS) to cooler (PLA) can be a problem if a bit of filament gets left behind in the hotend or nozzle. When going from hotter to cooler filaments, I just run the temp up above the highest I've printed at (265C is usually good) and run cleaning filament through. Then I'll let it cool off and do a cold pull.

The beauty of the cleaning filament is that it melts over a wide range of temperatures, so it'll get hot enough to melt anything I've printed with, but will also melt out at PLA temps and below, so the filament I've used for cleaning/cold pull itself doesn't cause problems.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 23/07/2021 3:21 pm
Livius
(@livius)
Eminent Member
Cold pull cleaning filament temp?

@bobstro

Do you cold pull the cleaning filament?  What temp do you cold pull the cleaning filament since it has such a wide temp range?

Posted : 27/07/2021 12:00 am
jsw
 jsw
(@jsw)
Noble Member

My usual procedure for the cold pull is:

Cut a length of cleaning filament.

Loosen the extruder idler gear.

Heat the nozzle to 280c or so.

Feed the cleaning filament into the extruder and push it until you get a couple of inches out of the nozzle.

Set the nozzle temp to cooldown, but keep slowly pushing the filament until it cannot be pushed any more.

When it gets down to 80-85C or so, quickly pull out the cleaning filament.

Rinse-repeat if there's a significant amount of debris on the tip of the filament.

Now my 'other' printer, the Ultimaker S5, has all of the above automated, and it 'talks you through' the steps and lets you choose PLA or cleaning filament as the cleaning medium.

Posted : 27/07/2021 1:25 am
Livius liked
cwbullet
(@cwbullet)
Illustrious Member
RE: cold pull

 

Posted by: @jsw

My usual procedure for the cold pull is:

Cut a length of cleaning filament.

Loosen the extruder idler gear.

Heat the nozzle to 280c or so.

Feed the cleaning filament into the extruder and push it until you get a couple of inches out of the nozzle.

Set the nozzle temp to cooldown, but keep slowly pushing the filament until it cannot be pushed any more.

When it gets down to 80-85C or so, quickly pull out the cleaning filament.

Rinse-repeat if there's a significant amount of debris on the tip of the filament.

Now my 'other' printer, the Ultimaker S5, has all of the above automated, and it 'talks you through' the steps and lets you choose PLA or cleaning filament as the cleaning medium.

That is my procedure also.  I will also purge a little filament once I get it fairly clear to ensure it is actually clear.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 27/07/2021 2:02 am
bobstro
(@bobstro)
Illustrious Member
Around 140C
Posted by: @livius

@bobstro

Do you cold pull the cleaning filament?  What temp do you cold pull the cleaning filament since it has such a wide temp range?

I leave the cleaning filament in after extruding, let it cool down completely, then heat the nozzle up and do a steady pull at about 120C. It usually comes out cleanly around 140C.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 27/07/2021 2:33 am
cwbullet
(@cwbullet)
Illustrious Member
Cold Pull

 

Posted by: @bobstro
Posted by: @livius

@bobstro

Do you cold pull the cleaning filament?  What temp do you cold pull the cleaning filament since it has such a wide temp range?

I leave the cleaning filament in after extruding, let it cool down completely, then heat the nozzle up and do a steady pull at about 120C. It usually comes out cleanly around 140C.

 

Interesting.  I have never heard of complete cooldown and reheat.  I will have to give it a try tonight.  I have an Mk3S that needs this sort of attention.  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 27/07/2021 8:29 am
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