PETG collecting on nozzle

Help with printing with specific plastic filaments.
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PeterT
Posts: 156
Joined: Mon Jan 04, 2016 5:50 pm

PETG collecting on nozzle

Post by PeterT » Wed Mar 16, 2016 3:06 pm

Hey guys, I finally got my PETG dialed in, and am printing some great parts. Here, I am printing about 36 tank treads for a rover I'm going to start soon, however, as clean and accurate as the parts are (really happy), you can see that I'm getting unsightly buildup on my nozzle.

My biggest fear (and have experienced it already) is that a glob will catch on one of the parts and leave a mound of plastic behind. So next time the head comes by, well, its not pretty.

Here are my specks:

Nozzle: 240
Bed: 80
Filament size: 2.88
Flow: 100%

Part is being printed at

Layer height: .25
Fill: 40%
Attachments
IMG_4813.JPG
Taz 5
Misumi hardened rods and bearings
Piercet Anti wobble Z-nut
Raspberry Pi w/ Octoprint and remote power control
Aerostrudder Head

catzcradle
Posts: 97
Joined: Sun May 17, 2015 11:15 pm

Re: PETG collecting on nozzle

Post by catzcradle » Wed Mar 16, 2016 3:49 pm

I have found of all the filaments I've used so far, PET is the biggest pain to get off the print head. It does gum up on there, and at least on one of my printers would occasionally leave a little bleb. Though oddly enough, it was extremely rare for it to leave it on the part, it always seemed to leave it on a string. On the Taz5 at least, I ran 3 rolls of clear PET over the course of a month, and while the head looked like crap from all the melted plastic, it never left a problem on the parts. On my other printer, a Makeit pro, I would get them, but they popped off the parts pretty easy as they never seemed to drop off in the middle of the print, but on a side wall. Though I will say in looking at your picture I'm not sure I ever had that much of a build up around the nozzle.

wmgeorge64
Posts: 410
Joined: Wed May 27, 2015 7:28 pm

Re: PETG collecting on nozzle

Post by wmgeorge64 » Thu Mar 17, 2016 6:39 am

Go to your local supermarket or home improvement store and get some Scotchbrite pads, green color and found in the dish washing or cleaning departments. When the nozzle is hot just wipe as needed. Caution the nozzle will be hot and you could burn your fingers.
Been using them for over a year, toss out when worn or full of plastic.
ULS Laser . Retired master Electrician in Iowa USA Lots of Hobbies

Sebastian
Posts: 514
Joined: Sun Sep 13, 2015 5:54 am

Re: PETG collecting on nozzle

Post by Sebastian » Thu Mar 17, 2016 10:24 am

If you have so much buildup, i would recommend you to check your esteps calibration. I guess you are over extruding. PETG is the last forgiving material when it comes to over extrusion,you have to be precise!

PeterT
Posts: 156
Joined: Mon Jan 04, 2016 5:50 pm

Re: PETG collecting on nozzle

Post by PeterT » Sun Mar 20, 2016 6:27 pm

Nailed it! Check out the image. After catching some insight from another page (posted in a separate post), I started adding .1 increments to my Z. Offset, thinking, either I would eventually get the head to stop the buildip, or eventually loose adhesion.

Well, adhesion is working fine, and the nose is completely clear of buildup at 50% of print. By now, if have a glob that would threaten to release.

Ended up adding .3 to the Z offset. (By incements of .1 per attempt.

P.S.

My esteps are dead on, that was one of the first things I adjusted :)
image.jpeg
Taz 5
Misumi hardened rods and bearings
Piercet Anti wobble Z-nut
Raspberry Pi w/ Octoprint and remote power control
Aerostrudder Head

daggius
Posts: 50
Joined: Fri Feb 05, 2016 12:56 am
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Re: PETG collecting on nozzle

Post by daggius » Sun Sep 25, 2016 1:49 pm

thanks for z offset tip. Havent used this before but will try since having same exact issue of nozzle buildup. Since this is controlled in the machine settings, i guess you can't keep it with the material profile, so have to remember to reset it every time working with petg?

daggius
Posts: 50
Joined: Fri Feb 05, 2016 12:56 am
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Re: PETG collecting on nozzle

Post by daggius » Sun Sep 25, 2016 4:48 pm

.3 offset works well. still getting some buildup but much less than before :)

PeterT
Posts: 156
Joined: Mon Jan 04, 2016 5:50 pm

Re: PETG collecting on nozzle

Post by PeterT » Mon Sep 26, 2016 3:14 pm

daggius wrote:.3 offset works well. still getting some buildup but much less than before :)
Sweet. You can increase offset. Like I said, until you lose adhesion to the build plate, you can keep going. Also, you may try compensating if you do loose adhesion by trying to increase the initial layer height something like 125-150%.
Taz 5
Misumi hardened rods and bearings
Piercet Anti wobble Z-nut
Raspberry Pi w/ Octoprint and remote power control
Aerostrudder Head

daggius
Posts: 50
Joined: Fri Feb 05, 2016 12:56 am
Contact:

Re: PETG collecting on nozzle

Post by daggius » Fri Dec 02, 2016 12:44 pm

PeterT wrote:
daggius wrote:.3 offset works well. still getting some buildup but much less than before :)
Sweet. You can increase offset. Like I said, until you lose adhesion to the build plate, you can keep going. Also, you may try compensating if you do loose adhesion by trying to increase the initial layer height something like 125-150%.
cool. i settled on 0.15 offset. most of the buildup occurs at the beginning when trying to get the first bit of goo flowing smoothly and sticking down, if i deal with that with the tweezers, then rest of printing goes well with the minor offset

wgsusa
Posts: 1
Joined: Fri Jul 12, 2019 12:59 pm

Re: PETG collecting on nozzle

Post by wgsusa » Fri Jul 12, 2019 1:21 pm

PeterT, Thank you for the information in this post. I had exactly the same problem, and by increasing my Z offset by 0.1mm it completely resolved the problem.

Also, since I happened to be printing with some fancy translucent red color filament, I notice now the color matches almost perfectly what I've printed vs. what was on the spool. So I must assume I was dragging the nozzle over the filament that was already laid down, previous to raising my Z offset.

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