K2 Plus TPU Printing - How I print TPU

[Chris.S_NZ]

When you print filaments that are not the 3 defaults CR has settings for, (or even sometimes with the brands to fine tune)…
when you run PA & Flow calibration, it populates the details of what it did those 2 tests results, into both the console & dashboard of fluidd… But it doesn’t save them for reuse.
i.e.

(its easier to see the results in the dashboard than going to the console)

you take these settings and edit the system filament setting (generic or CR, whatever TPU you are printing) & update the values in here, then save a “user” profile… next time you print using this saved profile, you a) don’t have to run calibration to get the same values used, b) save filament & time.

(you can choose to use PA or not depending on if you increate speeds from slow TPU printing or not)

running calibration gets you the numbers you need for a custom profile, creating a custom profile gets you consistent printing at “good” flow & PA ( if PA used) values.

it also shows that your setup “can” print TPU at the lowest speeds…
once you have this, you can run a print speed calibration tower, or just increate via fluidd until you see negative effects during a print), to know what max volumetric flow to set in the custom profile. this gives you “slice - send to printer - walk away - it will work values”… that should you want to you can increase speed of during print for faster prints if the objects / layers are simple geometries (up to the max speed test values)…

these are the basic steps, to deterime how fast you can consistently print (for any filament type), so that you buy more filaments (same brand) in future, and not have to do any of this again, you have a saved profile you know “just works”

once this is setup/saved, you can confidently via your mobile app, see something you want to print, cloud slide using your filament settings/profiles, send to printer & get things to print, without any faffing around wondering if it will work or not.
means you don’t have to do calibration every time to get something to print well… you have saved profiles for different things (strength vs fast vs detail etc) if you combine that with a saved bed mesh (per heating temp, per nozzle size, per bed type) you load via the nozzle gcode start print sequence, you cut out about 15-20 minutes per print if you are switching filaments a lot (PLA 0.8 on a smooth bed to PETG 0.4 on a textured bed to TPU etc)

[Chris.S_NZ]

Fyi, you never need to run the CR menu “calibration” options for PA & flow, as those are the 2 that are run when you send a print to the device and don’t untick the " run calibration" button, on the preview page . These 2 tests are the left hand side squiggly lines and right hand side rectangular strip… So while good you are calibrating, you don’t need to run specific “calibration tests” to get these 2 sorted.
Fluidd captures these and displays the optimal values from it’s self calibration & scan “only while printing the object”, so capture fluidd info while your project is printing

[hellcat_6]

Thank you for the detailed reply. I really appreciate you taking the time to explain. I’ve never heard of Fluidd but looking into it. I’m new to the Klipper FW stuff and will take some time to look into these. One side note of the issue i’m still experiencing with this Sain Smart translucent TPU is this area I have highlighted. Although not as severe, the “kink” shown keeps happening after a certain amount of time during a print. This is the area that gets sucked into the extruder gears.
-is there too much retraction?
-or is there not enough force on the extrusion gear because i put in a less stiff spring?

[Chris.S_NZ]

Fluidd is your printer web interface, browse to {ip address of printer}:4408 (found in your printer network setting page)
And it will load this web interface. I recommend setting a static IP via your router to the printer that way each time you turn it on you don’t have to find the IP address from the machine .

That looks like too much retraction to me…what settings are you running ? I use 0.2 using the non-spring method

[hellcat_6]

I was using 0.2 for retraction but with the spring method. I’m going to try your non-spring method this evening. I’ll let post results. (FYI, I used three TPU colors, all Sain Smart. Opaque orange and black, translucent blue. Only the blue fails this way.)

[Chris.S_NZ]

Hmm, while I’ve not used translucent tpu I can guess what the issue is, with PETG the translucent colours require a different profile to the solid colours, in order to print well… this is due to different processing/content in the filament

So if my non-spring method gives you the same results, make sure you run a temperature calibration, + auto calibration & at the translucent start of the print, to check PA & flow values against your solid TPU profile, I suspect they will be different from solid to translucent TPU profile…

I only rarely print TPU with PA enabled, mostly with it disabled but I use the PA auto calibration values to check filament tension in my setup… i.e a low PA auto calibration number means easy flow, a high PA number means it’s got more drag, requires more force to push the filament through when extruding…
I try to tweak my finger tightened screw method to get the PA values to lower end of the scale, to avoid the extruder push fail that creates the meters of filament into the enclosure out of the side of the extruder. Too low PA and you can’t increase the speed above very slow printing speeds

[hellcat_6]

I used the screw only method with a spring under the screw head to keep from backing out. I set the screw depth to a nice point where I could insert the filament thru the gears, pull back all with enough pressure to turn gears without slip. Set retraction to 0.2. I’m not sure how to use auto cal values. I clicked on run Print Calibration before sending to printer. It was looking promising, but same thing happened after 1 hour 16 minutes. The filament sucked into the gears and stopped extruding.

I have access to K1 and Ender at work. I may just bring the spool in and try on one or both of those. I wish Creality would either state that they do not think this material works on the K2 Plus or provide a soluton. I don’t think I’ll buy another Creality printer if it’s not going to perform as sold.

[Chris.S_NZ]

Fair enough, if you do have another go, ensure you set the max volumetric rate to very low, 2mm/s ,
Turn of PA via your profile, and slightly loosen the screw (if you can post your PA value via the auto calibration might help other to fine tube theirs)

FYI, ender 3v3 prints tpu easily, just remove ptfe and use a top mounted spool, I printed lots on my old printer.

[hellcat_6]

I will do. I was just venting. The K2 is a great printer with PLA as it’s the only other material I’ve used. I’ll try again with max vol at 2 mm^3/s. I was set at 3. Where is this auto calibration?

[Chris.S_NZ]

On the machine itself, via calibration tab, next to the filament menu…
There are 2 boxes, that control what tests actually run, when you choose auto calibration from the CR software.
On Mobile app you can change these (or via system menu) 3 dots top right, then

Then when you either use CR software on a computer in preview - screen, send to printer, there is an auto calibration button usually enabled by default…

This option, runs which of the 2 on the system are enabled .

So if PA is enabled on the K2, running auto calibration as part of a print, prints the squiggly lines on the front left of the bed.
This tunes the PA values which are displayed in fluidd

Note, this isn’t saved anywhere … so if you don’t have a “filament user profile”, and only use the system profiles for filaments, then you have to run this test every print, wasting time and filament. To get good prints. Saving this as a filament user profile allows via CR object menu to choose K2 filament with these settings, so you get good consistent prints.

Everything effects PA and flow the 2 values tested in auto calibration (which is why those 2 are now part of the part of print sequence by default enabled), the length of PTFE tubing, how wet the filament is, how old the CFS rollers are, size of nozzle, nozzle temperature… Etc…
Even switching the same filament from CFS to side spool, these 2 values will be massively different, and effect printing results .

when I printed this ball in TPU, its imperative that PA is disabled, or else you can’t print things like this, you just use PA “values” to dial in the spring (or in my case screw tension)

(black is TPU, green is PETG) prints perfectly without a brim or any supports…
any major configuration change, (like changing nozzle size, or printing an entirely new filament not printed before) if not Ok with adjusting values via fluidd on-the-fly, while printing, then running the basic 4 tests + a 1st layer calibration is a must… So many people complain about K2s (and they are partially right) but they also don’t do the basic 4 tests to dial it in.

https://wiki.creality.com/en/software/update-released/Basic-introduction/calibration-tutorial
+
first 1st layer test, something “like” (but never pay for one, you can create one in 1 minute, its a bug bear of mine that others fleece newbies for something that takes less than 5 minutes to create from scratch)

[hellcat_6]

Thanks for the info. I will give it a go when I get some time.
I printed on the K1 at work and it was not that good.

I’m beginning to think the filament is not that great or I just haven’t found the right parameters.
I printed the Benchy on the K2 and it turned out fine, using the non-spring method you shared.

[hellcat_6]

a little stringy…temperature too high?

[Chris.S_NZ]

Either temp too high or retraction distance/speed…

If you are printing low volumes just play with the settings before next print, if you want to dial it in use the temperature, & 2 retraction calibrations…

One thing I’ve not played with yet on my K2 is firmware retraction, on older ender 3v3 that worked really well, but I’ve yet to play/enable that to see if it’s any good on the K2 yet, or not. requires changing from klipper to Marlin 2, and I’ve not had the time to see if it works on K2.

Fwiw transparent filaments are the hardest to fine tune… but once you have it working they look good.
I print transparent PETG stuff…

This is the type of things I make/print… using transparent petg, sunglasses holders (or ABS QI phone charger/stands )

[hellcat_6]

That’s cool. I have not used PETG. I also print stuff that I find useful. If I have something made of plastic and it breaks, I’ll reverse eng it and print. I found myself at one point wondering where I was going to get a replacement part for a three-corner support for shoe shelf and I slapped my forehead and grabbed my calipers. Cheap plastic ones were breaking. So I printed 24 of them and replaced.
Pic is on my work computer which is not on at the moment. Another on is to replace a closet rod collar for wall attachment.

I ran the PA and Flow cal on the printer, or turned it on and run a test cube. the cal prints did not work too well. Was not sticking to the plate. Cube looks good. I really don’t know what I’m doing with the calibration stuff. I need to watch youtube vids or something. although, I am pretty tired.

[Chris.S_NZ]

just follow the instructions in this page at some point…

@Chris.S_NZ

Calibration Tutorial | Creality Wiki

[hellcat_6]

Thanks Chris. I have reviewed it but being a little thick on it. I’ll revisit it and try with PLA. Maybe TPU is messing me up

[Chris.S_NZ]

Yeah, above is just the process, to apply to any type
I have TPU, PLA and PETG *4 user profiles, for 0.4 nozzle on 2 beds, smooth CF and the stock one it comes with, and separate profiles for side spool vs CFS
Still building out other nozzle size combinations as,when I actually print with different nozzles, which isn’t that often.
Its a lot of profiles, but with using 3 different brands of filament you end up with a lot of profiles
This is where RFID tags come in handy…

[hellcat_6]

Interesting. I was reviewing the specs for the K2 Plus Combo and I noticed this:

Supported Filaments
PLA/ABS/PETG/PA-CF/PLA-CF/PET/ASA/PPA-CF

I was wrong. There is no mention of TPU. So, I guess I can’t argue Creality is misleading on ability to print TPU. However, someone figured it out and we can print some TPU on the K2 and I can live with that.

[hellcat_6]

And the K1 Max. I should have kept it:

[Chris.S_NZ]

This is on the Creality Wiki
https://wiki.creality.com/en/k2-flagship-series/k2-plus/print-tpu-filament

The biggest issue is that the CFS can’t handle TPU, it just jams too easily.

IMO the disabling PA, slow retraction speed/distance & max vol speeds are the most important, if you slow it down to 2mm/s and lower retraction to almost nothing, it works, well it does for me anyway… Using this screw instead of spring replacement method…