RE: TPU (Ninjatek Ninjaflex specifically) on the XL
I’m having the hardest problem all weekend trying to print Ninjaflex. Not a single successful print, all ended with filament jams. I’ve even had a few jams on the initial purge of filament off the front of the build plate.
When I open up the tool, the filament has jammed on the bottom. Just before the nozzle’s barrel.
Any ideas?
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
Couple questions.
Are you using .6 or .4mm nozzle? Have you dried your ninjaflex. Are you printing in an enclosure. I've only had the the filament get caught up in the gear on the xl maybe twice. This nearly happens always when you're trying to print too fast for the given temperature. I just did that coaster print using your settings, and 3 of my 4 colors were ninjaflex. It's possible that if you're not printing in an enclosure you might need to up your temperature so there's less back pressure. Your 235 printed great for me at the slow MVS. However printing with tpu is like trying to feed a wet noodle through a needle. The temp at the nozzle will affect the viscosity of the molten filament. if you're feeding the filament faster than it can ooze it out the nozzle, the filament will bend and get caught in the nozzle. If you're not printing in an enclosure, you might need to up your nozzle temp a few deg. I'm printing in an enclosure so the environmental temperature won't tend to vary throughout the print. How tight do you have your idlers on the extruders? The wisdom of super loose like it needed to be on the MK3 doesn't hold with the XL or the MK4. I recently went through this exercise for the XL. I ended up having to tighten them up a bit.
I’m having the hardest problem all weekend trying to print Ninjaflex. Not a single successful print, all ended with filament jams. I’ve even had a few jams on the initial purge of filament off the front of the build plate.
When I open up the tool, the filament has jammed on the bottom. Just before the nozzle’s barrel.
Any ideas?
RE:
I'm using a 0.4mm nozzle. Ninjaflex is dry, and I keep them in a sealed dry box with desicant.
Prints are jamming with my settings, I'm even having problems loading the Ninjaflex filament and having it jam when it's trying to purge. Today I've reseated the nozzles and made sure the filament path is clear of debris.
I haven't touched the idlers, they were working fine before. I haven't gotten around to make an enclosure yet.
Come to think of it, problems started after the winter weather finally arrived. That might be the problem.
I'll try upping up the temps a few degrees to see if that helps with the jamming.
Thanks for the sugestions,
S.Lam
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
Yep. My printers are downstairs in my basement and there’s a pretty big temperature swing overnight and it’s more pronounced in winter. I’ve definitely seen the case where that swing causes a working config to suddenly fail. It’s a big reason all my printers are in enclosures.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
I got brave and did some sainsmart too.
Left was 228 @ 1.1 stock extrusion multiplier
Right, Small adjustments from the stock setting. 227 instead of 230 and .99 extrusion multiplier
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
Did a few prints this week and I found 235 is too finicky. I had one case where the filament jammed and exactly had a big loop of filament coming out the side of the extruder. The other it stopped extruding. 238 seems to be the sweetspot with a 1.2mm^3 MVS. I still feel like it might be possible to inch the MVS up, but at this point I'll take reliable and no jams over faster with failed prints. Ninjaflex isn't cheap. Thanks to @slam for pointing me in the low MVS direction.
I got this 5 color print working pretty well. The yellow is sainsmart pastel 92A tpu and the rest of the colors are ninjaflex. Sainsmart works with the only change from stocking being the temp at 227 to prevent stringing.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
I fixed the gap too!
This turned out great. I'm not sure how to fix the the little gap in the white near the top of the filament, but reducing the mvs and temp as @slam suggested really improved things!
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
This is 4 colors of ninjaflex with sainsmart clear as the base. The retraction change made a huge diff
Final settings for ninjaflex, Assume starting with the Ninjaflex stock profile
238C
1.2 MVS(I think this could be higher with the retraction changes, but I've not tried it.)
Retraction length 1.5(down from 3.5)
Retraction speed 20mm/s(down from 60)
I think the periodic jams(in particular with chinchilla) were because the filament would bend in the extruder when the retraction happened with the length plus the speed. The stock sainsmart profile has the retraction length at 1.5, which is what made me think to try it for the ninjaflex.
I've printed a couple of these coasters with those settings now and so far so good.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
I've probably printed 6 or 7 of these coasters now, no jams.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
Hello Mate,
I still am not able to reliably print my TPU which is actually pretty "hard" 98a and I tried everything I could think off. Retraction is at 0.5mm in the filament override. I printed fast, slow, warm and cold. I checked the extruder a thousand times and adjusted the extruder idler springs many times. Always the extrusion gets super thin after a minute or two. Like it only extrudes 10% of the material. Of course that makes a thin Hairlike substance on the build plate and not a solid structure. Flow Multiplier doesn't help either.
One thing I noticed - the Filament seems to be more like 1.68mm, but that can not be the problem right? Any Idea?
The print itself is really simple and quality in terms of looks isn't important, but I want to know why it does't work.
Maybe one hint: I printed small Parts of the Polycarbonate with an enclosure. The printer got to 40c° in the build volume for like 20 hours total. That can not be big problem right? It was already some time ago and with a different nozzle. Also the enclosure is taken off for TPU.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
Have you bypassed the filament sensor on the side? That was the first thing I had to do. The ball bearing and spring created too much drag. In my case I ended up just taking the ball bearing and spring out and turning them off. The way I knew it was filament sensor was that like you it started extruding but was severely under-extruded. if I pushed on the filament manually to help it through the tube the extrusion got better.
I'd definitely route around the filament sensor and give it a try. It makes me wonder if they tested tpu at all when they were developing this.
Hello Mate,
I still am not able to reliably print my TPU which is actually pretty "hard" 98a and I tried everything I could think off. Retraction is at 0.5mm in the filament override. I printed fast, slow, warm and cold. I checked the extruder a thousand times and adjusted the extruder idler springs many times. Always the extrusion gets super thin after a minute or two. Like it only extrudes 10% of the material. Of course that makes a thin Hairlike substance on the build plate and not a solid structure. Flow Multiplier doesn't help either.
One thing I noticed - the Filament seems to be more like 1.68mm, but that can not be the problem right? Any Idea?
The print itself is really simple and quality in terms of looks isn't important, but I want to know why it does't work.Maybe one hint: I printed small Parts of the Polycarbonate with an enclosure. The printer got to 40c° in the build volume for like 20 hours total. That can not be big problem right? It was already some time ago and with a different nozzle. Also the enclosure is taken off for TPU.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
Ohh yes - I have done that really early. I also checked how hard it is to pull through the filament by hand when I detach the PTFE tube from the top of the extruder and it goes through really smooth without the side sensor.
Have you bypassed the filament sensor on the side?
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
I've printed a lot of TPU, TPE, PVA and other soft filaments by changing the feed route from the side, with the many curves, to one from overhead with a single 90 degree turn and half the distance. I haven't changed the set screws on the gear tension. Haven't changed any of the feed rates. Just feed from overhead. It completely solves the issue of the complex path and all the drag.
The filament sensor is bewilderingly loaded with drag. A magnet design is far better and far more reliable than the spring and ball nonsense. I'm betting the engineer for that part is an intern.
Here's my setup:
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
I've probably printed more tpu in the last 2 weeks than I ever have lol. I feed from spindles that have 608 bearings and that seems to be sufficient.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
That's another irritating source of drag: The silly spool holders that Prusa supplies. I printed much better ones with printed bearings because of the squeaking and grinding noises from the supplied spools. I want to be able to spin the spool and have it take at least five seconds to come to a stop silently, not grind and squeak to a halt in half a second.
Changing out spool holders for one with a bearing should be one of the first upgrades people do when they get their XL.
I've probably printed more tpu in the last 2 weeks than I ever have lol. I feed from spindles that have 608 bearings and that seems to be sufficient.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
I made the mistake early on with the XL to loosen the idler tension a lot. This was what you had to do on the MK3S to get tpu to print. But on XL it needs to be rather tight. But I've been doing back to back prints of this coaster, making them as gifts, and it's going well.
@acht What MVS are you using? Is your filament backing up into the extruder gear? Here's what I would try to rule out retraction. Try printing a 100mm square that's .2mm tall. This will basically just focus on getting the filament out of the nozzle for a minute or two. If it stops extruding before it finishes the square, you're probably not printing hot enough, or too fast. In this case, you need play with lowering the MVS and maybe increase the temp by 5 deg. If you can get a complete square then move on to printing a 20mm xyz calibration cube. if you start getting jams with the cube, then that's when retraction could be coming into play. with a 98A, you shouldn't really be running into problems unless you simply aren't printing it hot enough, or you are printing too fast.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
Yep I needed some with bearings and that worked with my enclosure so I designed some. The are up on printables, they will work without the enclosure also. Bearings are so cheap that that it's silly not to use them.
That's another irritating source of drag: The silly spool holders that Prusa supplies. I printed much better ones with printed bearings because of the squeaking and grinding noises from the supplied spools. I want to be able to spin the spool and have it take at least five seconds to come to a stop silently, not grind and squeak to a halt in half a second.
Changing out spool holders for one with a bearing should be one of the first upgrades people do when they get their XL.
I've probably printed more tpu in the last 2 weeks than I ever have lol. I feed from spindles that have 608 bearings and that seems to be sufficient.
Bearings are so cheap that that it's silly not to use them.
Don't throw away the Prusa holders too quickly. I have rotated my filament sensors and mounted the holders above the printer - and I printed one with bearings. It tended to overrun spilling filament so I've readopted the Prusa holders. Use #8 pan heads to screw them to the wall.
Cheerio,
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
Cautionary tale lol. Never forget the XL is a wild animal. I got cocky. Printed a bunch of these coasters. so I left one running while I was working and I wasn't paying attention.
I had this happen. Interestingly it's because my one sainsmart filament jammed. fortunately with this you could use scissors to get most of it and then heat up to temp and use a brass and nylon brushes to clean up the block.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
@ssill2, ouch. That's gonna leave a mark!
After reading all the issues several have reported about printing TPU I decided to give it a try and chime in with my results. I don't print much of this stuff but when I need to, I certainly want to be able to.
Recently I installed this upgrade by @Kaaaaaaaaaaaa_222966 to minimize the chance of it getting wrapped around the gear. Currently it's only on tool five, which I ran this test from to make sure I didn't cause any other issues.
https://www.printables.com/model/741152-xl-nextruder-main-plate-and-idler-lever-for-flex-f
After bypassing the side filament sensor I could not, for the life of me, get the second sensor (at the head) to trigger even though the filament was past it. I had to disable all filament sensors. Once disabled the filament loaded/purged fine and even printed decently, or so I thought.
As a baseline I used the unmodified 'NinjaTek NinjaFlex TPU @XL' filament profile; this is exactly that filament in 'Snow White'. It is a few years old now (again, I don't print much of it) and it certainly needs further dried since I only had it in the dryer for maybe an hour. It is always stored in a sealed box with desiccant though.
While watching it print I noticed that most of the blobs came from the circular retraction moves. 'Avoid Crossing Perimeters' was not enabled for this baseline.
A zip line and personal best string here! Definitely need to dry this overnight.
Looks decent at first glance but then after closer observation I realized there is some serious under extrusion, guessing from the long ride through the PTFE stretching it out, as several have already discovered.
Zoom in on this one and you can see everything is under extruded.
Obviously there is a lot of work to go for nice TPU prints. I also have some Hatchbox Black TPU that's shore 95A. Wonder if that'll work any better all things being the same.