eSUN PETG Q & A

I have seen more and more questions related to the tuning of eSUN PETG.  There is a very good and very long post on makergear forum.  The info are so useful that I have decided to summarize here for easy troubleshooting.  Still, if you have more questions, the makergear forum "esun petg" thread is a great place to get help.  There are many experienced eSUN PETG user there willing to help you.

(first draft 08/13/2015. will get better :))

(Added Jules' setting post link)

Q:  What is the best settings for PETG:

A: One of our client has made a great post on PETG settings.  Anyone who has trouble getting PETG dialed in, please take a look at the post:

https://www.xyzfabs.com/forums/topic/63/print-settings-for-petg-esun-solid-black-filament 

Q:  Metal bed vs. glass bed and the first layer sticking problem.

A: I've found the PETg filaments to have very well-defined cut-off points between sticking well and not sticking at all, both for the extruder temperature and for the bed temperature. On the glass bed, that temperature sits right below 90C for all of the filaments. I print at 90, and when it's holding that temperature, the part is stuck firmly and can be very hard to get off even with a razor blade. As it cools down, somewhere around 80 it loses adhesion completely, and often I can just pick the part right off the glass. The difference between your experience and mine may be due to the temperature that the bed can keep on the surface when the fan is blowing on it. That must be different for a metal bed vs. a glass one.

I"m using hairspray, my favorite being Suave Max Hold in a pump spray bottle. I like the pump bottle. It makes a nice thick layer in a relatively small area and doesn't float around in the air. (from Tim)

A:  I am using glue stick.

I have done dozens of hours of printing yellow and blue, and I can't think of ever having a part come unstuck, nor do my parts come off easily as the glass is starting to cool. Unlike JSC, I do not have to use a lot of glue and get the same results with a fresh ultra-thin layer or a heavy layer.

I am printing at 90C bed and 255 on my E3D nozzle. I used to print at 110C bed and that was fine too, though proved unnecessary. I am using cooling fan but my fan is way more powerful than stock. In fact, if I use it at 100%, my hot end won't go over 225C.

My impression is that this filament is not challenging to print with, providing you do what JSC says and not print over 60 mm/min and print the first layer at 50% speed. I printed on bare glass with PETG at 90C and it stuck well.

(from rsilv***)

A:  if your in s3d and you increasing the first layer height your doing nothing because when you use that setting it also increases the plastic flow. if your are wanting to increase your gap via the software you need to goto to gcode tab and enter an offset for the z axis. remember all those first layer settings also change plastic flow to compensate. here is a link to something i made a long time ago to help with this. remember that when the first layer extrudes each line should just touch. they should not be super flat or squished together.  (from Jim)

http://www.thingiverse.com/thing:180970

A:  petg sticks great to a hairspray treated bed. you really should not need a raft with pet. the stuff barely warps. you really need to get your first layer dialed in so you get 100% contact with your build surface. pet does not like to be squished onto the surface. if you do it just collects on the nozzle.  (from Jim)

Q:  for some reason I am getting a ton is stringies in my  PETG that eventually catch and build up on the nozzle.

A:  what is going on there is the support. its dragging the extrusion all around because of the 1 layer gap between the support and the first layer of the print. support for pet sux. the stuff bonds together so well if you do use support it can be a pia to remove. if there is the standard 1 layer gap then it drags the filament around like that. its just like having the bed gap set way too big. something to try is get rid of the dense support layers. you dont want that with pet because youll never remove it. set your infill to maybe 30%, remove the 1 layer separation gap. at 30% it shouldnt be too hard to remove. another thing to try is lower the layer height to .15. this will print that first layer .05mm closer to the support. have you done any calibration. if you are underextruding then the extrusion wont be thick enough to contact the support enough then it will break apart. when i measure my filament and set it correctly then my multiplier is .99-1.01. underextrusion will also show up as infill problems. it will be broken. not to do with your problem but for your infill settings, set the infill extrusion width to 140%, overlap to 25%. ok first thing i would start with is calibration. i have a feeling your underextruding. if that doesnt work move on to my other recommendations.  (from Jim)

A:  petg is sticky so any strings or overextrusion loves collecting on the nozzle. it tends to get these little micro fine hairs during jumps. this collects on the nozzle as well. a little more retraction and bump the temp down 5 deg at a time. as jin said, infill can be a contributor to the nozzle boogers. i found that if the infill does not go down nice and perfect and its broken or jagged then the parts sticking up end up on the nozzle. adding a little extra infill width usually cures this with s3d. just dont add too much. 120-140% is good. petg is a great material but its not as forgiving as pla. that window where it prints really nice is much smaller so you gotta dial it in really well.  (from Jim)

Q: I am running a Prusa i3. Collecting on the nozzle is what I am getting. I had my bed set to where I could drag the piece of paper between the bed and nozzle and it barely catches on the nozzle. But when I try to print with this PETG it just piles up on the nozzle. I have even slowed down to like 20mm/s

A:  yes your printing too close. the width of the extrusion on the first layer should equal what you have your extrusion width set to in s3d. right now it sould like your too tight and its just smearing all over. pet is sticky so any amt sticking up from either over extrusion or printing too close will end up on the nozzle. (from Jim)

A:  It will stick fine at 70c bed temp and 255c extruder. If it doesn't stick look to make sure your first layer bead is squished slightly.If not relevel bed and adjust z height. (from PSC)

A:  That's right. If the bed at the "Z-home" position is not close enough to the nozzle, the first layer gets air-printed, and it deforms and won't stick. If it is too close, the first layer gets smashed and it can cause a ridged first layer when the plastic has no where to go except out the sides.

With PETG, it really does stick to itself, so when the nozzle drags over the previous layer, it can hit those ridges and pick up wads of goo that fall off later. You likely have the nozzle too close to the bed on the first layer. (from Jules)

A:  I think I have it figured out. I run about 175% first layer height with 175% first layer width and first layer speed at 30% and it gives me a nice solid first layer that sticks amazingly well to my PEI bed at 80C. Once it cools to about 40C it pops right off  (from Griff)

Q:  What settings do people use for PETG?

A:  I've got a V3b extruder, .35mm nozzle. Printing on glass with old/used/burnished-with-a-razor glue stick -- it might actually have worked without, will try later. (Extrusion multiplier is .87, set to .40 extrusion width.) Z stop is set right at .005. (Again, initially forgot to reset it after the part swap; things were close enough I could get away with it on the slow calibration piece.)

S3D settings:
Retraction Distance: 2.00mm
Retraction Speed: 2400.0mm/min
Coast at End checked, distance .2mm
Wipe Nozzle checked, wipe distance 5.00mm
Layer Height: .2
Solid layers: 3
Outline/Perimeter Shells: 6 (I may boost this up a bit.)
First Layer Speed: 50% <--- don't miss this one!
Include Skirt, 1 layer 4mm offset 2 outlines
Interior Fill Percentage: 80 (I want this good and strong)
Outline Overlap: 25%
Infill Extrusion Width: 100%
Minimum Infill Length: 5.00mm
Print Sparse Infill Every 1 layer
Bed Temp: 100
Extruder Temp: 250
Fan Speed @ 100 on layer 2+
Default printing speed: 3200mm/min
<all> Underspeed: 60%
X/Y Axis Movement Speed: It's at 9000mm/min now (half the default I'd accepted for PLA & ABS) <-- I'll be dropping that way down too, still had some rogue stringing/pulling on the first layer's jumps but I let it go; what do people set this at for PETg?  (from Vpri**)

A:  for printing with support. 

Q:  I've started running into some PETG layer bonding issues. I saw a wall crack as it was printing and stopped the print. When I took it off, I could separate each strand by hand, like a hank of hair. The only change is my new super powerful fan and shroud. So maybe PETG doesn't care for tons of cooling. I'll try it without the fan.

A: Yeah i dont run a fan at all with it. Pet works with both fan or no fan. I usually run no fan but if its a small part or when i get to a layer where there are tiny features i know will get heat soaked a little i will turn the fan on for a bit.(from Jim)

I see. So use a fan if I am making, say, a small threaded bolt and not printing a bunch of them at once.

But for a normal large part, use no fan. (follow up answer)

Extruder calibrated at .40mm, no change in filament diameter, no fan running, pinrint at 255°C, adhesion problem between walls.

Increased extrusion multiplier 10%, that problem goes away.(from Jerey)

A:  PET+ layer adhesion was no where near the esun petg . Petg in general is a little harder to print but once you figure it out the benefits are definitely worth it .

Q:  Over extrusion collects on the nozzle.  How to clean it up.

A:  if you go into home depot. go in the tool section. they usually have a small section of welding equipment. in that section there are real small wood handle wire brushes. i grabbed a stainless steel bristle one a while back. every once in a while while the block is hot i give it and the nozzle a quick shot to clean off and built up crap. it does get shiny new or anything but does get off any buildup. (from Jim)

I chuck an M6 cap-head bolt into my drill, unscrew the nozzle (V4 for the win), and spin the nozzle against some 1000 grit sandpaper for a few seconds. Always gets 'em nice and shiny (yes I have several V4s also) (from Insta)

Q:  Some examples of printed products which show the strength of PETG:

A:  I printed my Carabiner in eSun PETG and I am pretty sure it would lift most people. Some very strong guys could not pull it open when printed at 2x size.

http://www.thingiverse.com/thing:737877  (from rsil***)

Q: What can be used to successfully glue petg parts together?

A:  Weldon #4 / methylene chloride (from Jim)  weld on or methylene chloride is extremely thin and is supposed to be applied with 28ga or smaller needle applicator bottles. not sure if you got one of those or not. it needs to be super thin like that because the parts are supposed to be assembled then you run the needle over the joint and the solvent wicks between the 2 pieces. its not really meant to be a gap filler. if it was thick it would not suck in between the 2 halves.

Q:  I've been trying to print Jules' battery box in PETG and have had two failures. The print is a flat wall, so lots of surface area. The failures occur in the fourth layer, once the solid bottom layers have finished and it starts going to infill. It starts out okay but then just peters out and stops. When I withdraw the filament, it looks fine except for the divot the gear dug, so it's not a heat creep problem.

I'm printing at 60mm/s with 200% infill width. I think that might be an issue, since the effective extrusion rate is something like 240mm/s (does that sound right? pi r^2...) I've printed successfully with these settings before, though, which confuses me. Maybe it's because those prints didn't have long runs of infill so the head never ramped up to full speed for very long?

A:  Turn your temp up 11 more degrees. (from rsilv***)

A:  absolutely it could be the issue. the back pressure is just so great that the filament strips out. i also had issues with 200% infill width. its just too much material to push out. i keep mine at 140 or below. on the other hand i was running a larger nozzle too which is even more material but smaller nozzle has greater back pressure trying to squeeze all the plastic through that tiny hole. im not really sure what that upper limit is as far as feed rate goes. in any case, that what it sounds like to me because i have gone through it many times trying to reach the upper limit on speed. small parts will print no problem but bigger ones strip out on infill. i have done it with petg and abs. unfortunately you con only melt the stuff so fast and with these newer hotends that have shorter and sharper hot zones the speed is cut down even more. i really havent had a need to go over 140% on infill width with pet. i would slow down a little or drop the width. also your temp should be 245-255  (from Jim)

A:  With my 0.4mm nozzle I have never had a problem with 200% infill as far as I know. But if it is a threshold thing where it is effecting people, then sure - I could see lowering it. It is the first thing I will do if I ever have a problem with jams. I think my dual 11,000 rpm fans are why my system has been reliable.  (rsilv***)

Q:  Clogging

A:  I was having massive clog issues on my all-metal v4 and esun PETG. A few changes have cleared it right up.

First, I got another PTFE lined extruder and used that instead. If you are using a PTFE lined extruder, make sure it is actually PTFE lined. Mine managed to arrive with neither liner nor cap screw....

Second, make sure you are printing slower than you would with PLA. 50-60 mm/s should do it. Increase your infill to 130%, but not much over that. Or 100% with one of the new every-layer infill patterns in S3D.  (from jsc)

Q:  black and white and new stocks ... what is weird is that seems to have a rough texture on the filament surface.

A:  the slight texture lets it slide through feed tubes easier.  The texture also gives the driver gear more traction to drive the filament into extruder.

Feel free to leave comments below and/or email to admin@intservo.com,  some experts will answer your questions. 

Thanks,

William at INTSERVO