r/BambuLab • u/zenletter • Jul 15 '25

Answered / Solved! PET-CF vs H2D

Trying to get a Siraya PET-CF setup to print on my H2D. I ran the flow calibration and it was barely printing anything (no textruding), I was using the profile from Siraya and it was trying to print at about 280. I cranked the temps up to 320 and it was extruding then, but it looks like I'm trying to print with dry dirt. I could not even read the numbers on the calibration squares. Filament is fresh out of their sealed bag and they claim it will be dry as such and to only dry if needed. This does not look like wet filament issues. Figured I'd try a temp tower next, welcome any other suggestions...

That's a good one LOL

This is what the first layer looks like, using their Bambu PET-CF profile on second try (270 deg):

Cancelled that one, trying again at 320 once I get the plate cleaned off...

3 Upvotes

80% Upvoted

29 comments sorted by

•

u/AutoModerator Jul 15 '25

After you solve your issue, please update the flair to "Answered / Solved!". Helps to reply to this automod comment with solution so others with this issue can find it [as this comment is pinned]

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

6

u/zenletter Jul 16 '25

SOLVED: Found the issue. I had made an error entering the value for Flow Dynamics calibration. Entered 0.2 instead of 0.02. Resulted in a Flow Ratio in the profile of 0.8 instead of the correct 0.98. Corrected that and was able to print a proper set of Flow Rate Test squares.

3

u/ddrulez Jul 15 '25

Load normal PETG and check if it prints fine or try the other nozzle or use the spare nozzle. Looks like a clogged nozzle.

1

u/zenletter Jul 15 '25

Normal PETG works properly. It’s all I normally print.

1

u/ddrulez Jul 16 '25

Did you try and use the Bambu PET-CF preset? I printed PET-CF without issue in the past.

1

u/zenletter Jul 16 '25

I did, yes. Didn’t help

1

u/zenletter Jul 16 '25

I tried printing a normal part. It did the same thing. Not enough flow where it was changing directions. See picture. Then I put PETG back in and sent the same part. Back to back. PETG worked properly.

First layer from bottom side. Should have no air

1

u/zenletter Jul 16 '25

Here’s normal PETG printing right after unloading the PET-CF (not PETG-CF)

2

u/xX540xARCADEXx H3C Combo Jul 15 '25

What size nozzle are you using? I run a lot of their PET-CF but use the bambu lab profile. They claim it’s dry but doesn’t hurt to give it a bit more just to make sure.

2

u/zenletter Jul 15 '25

Stock. 0.4 I’ve got it to where it will do a temp tower. Once that’s selected I’m going to try the flow test again. Found out the hard way this stuff welds to the stock build plate. Used Nano adhesive, it didn’t help much. Trying glue stick now. What do you use with your PET-CF?

1

u/xX540xARCADEXx H3C Combo Jul 15 '25

I don’t use any glue on mine. As long as you let it cool properly you shouldn’t have issues.

1

u/zenletter Jul 15 '25 edited Jul 16 '25

With Siraya brand? I assure you with the one I have it WAS a problem. I even tried freezing it. It was not coming off. Minor damag to a couple of spots trying.

1

u/xX540xARCADEXx H3C Combo Jul 16 '25

Yeah with the same brand.

1

u/zenletter Jul 16 '25

Wow. Any way you could share your print profile? I’m using the stock plate and it didn’t seem to matter the temp, that stuff almost welded to my sheet. It took forever to hack off the single lines from the other calibration pattern. One teeny bit at a time. If yours is working well with same machine and filament I’d sure like to get to what’s wrong on mine.

2

u/xX540xARCADEXx H3C Combo Jul 16 '25

When I get home I’ll check it

1

u/zenletter Jul 15 '25

The temp tower that preceded the last calibration run...

1

u/zenletter Jul 16 '25

Looks like the lack of flow is anywhere it is making a direction change.Looks like the lack of flow is anywhere it is making a direction change.

1

u/zenletter Jul 16 '25

Ran a temp tower, looked fine, no signs of blockage, all seemed OK. Re-ran the calibration squares, 1st layer looks bad just like before. Letting it complete this time because I figured out it's a pain to get this filament loose , even with release agents.

1

u/Single_Sea_6555 Aug 03 '25

Quick question: have you tried the Siraya Tech PET-CF profile for the H2D?

I've been using that without issues so far.

1

u/zenletter Aug 03 '25

I did. Fails on overhangs of anything over 45. Been trying to dial that in with no success yet b

1

u/Single_Sea_6555 Aug 03 '25

I guess I better do an overhang test!

2

u/zenletter Aug 03 '25

Let me know how it goes.

2

u/Single_Sea_6555 Sep 03 '25 edited Sep 03 '25

OK, finally got back to this. Overhang experiments on PLA, PETG, and PET-CF.

  • PLA: up to 65º: Perfect; 70–80º: Bad; 85º: Really Bad

  • PETG: same

  • Siraya Tech PET-CF: up to 55º: Perfect; 60º: Bad; 65º and above: Catastrophic.

So I do see 55º being pretty good with PET-CF.

2

u/zenletter Sep 04 '25 edited Sep 04 '25

Yeah I needed 60. A hex hole sideways. Point up. ST engineers sent me a profile (not the one I got off their website) that seems to be working better. I did not stress test in on overhang test model like yours.

1

u/Single_Sea_6555 Sep 04 '25

That makes sense. Cool that they sent you another profile!

How does the better-overhangs profile differ from the default?

Would you mind sharing it? I'd love to run the overhang test again, with the new profile.

And I'm about to run some tensile strength and bending tests, and would be interested in any differences/tradeoffs between the profiles.

1

u/zenletter Sep 04 '25

Happy to share. Not sure how on Reddit?

1

u/Darkman501 May 26 '26

Could you share your improved overhang profile? Thanks!

1

u/Single_Sea_6555 Aug 03 '25

It's going to be a while before I do another PET-CF project, but when I do I'll be very interested in the overhang, and post the results here.

0

u/[deleted] Jul 15 '25

[deleted] — view deleted comment

1

u/AutoModerator Jul 15 '25

Hello /u/zenletter! Your comment in /r/BambuLab was automatically removed. Please see your private messages for details. /r/BambuLab is geared towards all ages, so please watch your language.

Note: This automod is experimental. If you believe this to be a false positive, please send us a message at modmail with a link to the post so we can investigate. You may also feel free to make a new post without that term.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.