Adjustments for E3D Obxidian nozzle

Hey there, I have upgraded to a 0,4mm E3D Obxidian nozzle for my X1C some time ago.
As adviced, I have reduced temperatures by 10°C in all profiles because the temperature sensor sits opposite the heater instead of same side in the stock hotends

In many respects, the improvement is stunning me. For the materials I tested, maximum flowrate until first defects appear has increased from 21-23 mm³/s to 40-45mm³/s using the max flow test in Orca. I have set max flow to 35 for all materials, even non-HF ones.
Surfaces e.g. of regular PETG look the same from 100-300 mm/s.
And layer adhesion is now constant no matter if I print at 100 or 300mm/s and way better than it was at 100mm/s with stock hotend.

There are two things though that bother me and I hope to solve with your help:

1.) oozing during print preparation.
when the printer purges the nozzle, cleans it etc., there is a lot more oozing now. That gets dragged far more often on the build plate than before. I heard that this is typical for CHT nozzles. With the arrangement of heater and sensor in mind, I thought it would be a good thing if the printer reduces the temperature by 10°C during all those preparation steps. Eg do purging at 240 instead of 250°C, while cleaning, cool down to 130 instead of 140°C, …
Does anyone know if this is part of the gcode or is it hardcoded in the firmware? If in gcode, can someone point me in the right direction?

2.) insufficient purge at print start.
The second issue is very similar: Apparently the CHT nozzle needs far more purge volume to really clean the nozzle from the last filament. When starting a print with a different color or material, the first layer is usually still colored from the last filament. For clean prints, I have to manually load the next filament and push some through with the controls. I would much prefer, that the printer just purges more at the start of a print. Same question here: does someone know, if I can adjust that in the gcode?

To all users of an Obxidian or other CHT nozzle: Do you share my findings? Are there other issues I didn’t discover yet? Did you do something about it?

If there isn’t much feedback, I will ask E3D. The nozzle is expensive enough and developed in cooperation with BambuLab, so they should be able to provide the same experience as with the stock nozzle.

I am running one for many months now - replaced the original with it once I got fed up enough.
Have to say that I don’t encounter your problems as badly though…

  1. The oozing during purge is (IMHO) based on how Bambu handles things - we have no option to change the temps and such for the purge routines.
    What works (almost) fine with the original hotend can cause some headaches here and there.
    I encounter it mainly with PETG, not so much with PLA.
    And well, some filaments behave better than others.
    If really bad I add a skirt loop to ensure nothing too much is harming a print.

  2. The purge volumes are quite relative and again the main issue is that we can’t change any part part of it.
    I guess it comes down to the E3D hotends having a slightly larger melting chamber.

In general I am happy enough to never go back to Bambu hotends.
For most problems there is a suitable workaround, but for multi colour prints, or when using PLA/PETG for the interference layer checking those purge volumes prior to a meaningful print IS ADVISABLE.

In the past I used a dual head printer and in hindsight going Bambu really only provided a speed increase for my prints.
In terms of multi colour or multi material prints nothing beats a proper dual head setup.
Not sure if you noticed but a lot of info you can find online in unverified posts, Reddit or Youtube is rather misleading - to say it nicely.
Take the claim that these E3D hotends require a higher print temperature…
While the sensor location COULD have an affect, the heater still has to heat the entire hotend and the temp sensor only reads the block temp.
I found that in most cases my prints come out far better with a slightly reduced nozzle temp - compared to the Bambu hotend that is…
The higher print temps come into affect once you actually want to max out what the E3D is capable of.
But even there I rarely have to increase the nozzle temp, printing PLA at 200mm/s makes no difference to printing it at 500mm/s…
If you ask me then a good calibration, a complete one is what gets the butter on the bread here.

I too will not go back. The improvements are totally worth it. Even if I don’t make use of higher volume very often.
Regarding temperatures, I have the feeling that many think that more is generally better. E.g. PETG at 275°C sounds completely crazy to me. I guess they crank up fans to 100% and in the end have weaker bonds than at lower temps with low fans.
Anyway I think the reduction by 10°C is a direct recommendation from E3D, so I took that over without questions.

Thank you for suggesting the skirt, that could actually solve both of my problems :smiley:. Make it wide enough and you have added a “purge to skirt” :slightly_smiling_face:.

Had to print some glow PLA with the hardened nozzle and thought I fill in some more blanks…

What makes a high flow hotend so good and so complicated at the same time ?
A cheap standard hotend isn’t optimised for anything, just a tube with a heater and a tiny hole below.
A quality highflow hotend, no matter the manufacturer, is based on development and testing.
For one of my old printers I made my own hotends, was a matter of proving a point so to speak.
The originals failed quickly and the print quality was not that good either.
Last night when watching the hardened nozzle crawl around I realised that the story of my old hotends would make a good explanation…

It all started with a slightly heated conversation in a forum.
I said that I will make an all aluminium nozzle/heater block combo with stainless steel tube as a heatbreak.
A ton of people said it is impossible as Aluminium is too soft and called me a fool (to say it nicely) for stating I would wrap the heating wire onto the Aluminium nozzle.
Me on one side and a growing number of users making a mock out of me by saying things like “Hey dude, you do realise Aluminium is a metal and that metals conduct electricity?”
I worked as a sparky for most of my life, so I guess I noticed that metals are conductive.
Aluminium oxide on the other hand is an isolating material and almost as hard as diamond…
Long story short, I used my lathe to make the body and to add a ‘thread’ to hold the heating wire, followed by an aluminium sleeve to go over the lot after smearing some heat transfer goo onto everything.
Heated up within a few seconds while the original needed almost 90 seconds.
The plastic came out perfectly straight and as a string, rather than curling up right after getting out of the nozzle.
And of course, thanks to a good round anodising and a bit of blue food colouring I also had a quite thick and slow grown oxide layer everywhere.
The melting chamber was polished prior to the anodising…

What were the results you wonder?
In the forum I guess quite a few people were a bit #$%&^&*@ as they did not even bother to reply again once I showed the results.
For me though it was a real surprise as I did not expect a home made hotend would perform much better than what the printer manufacturer supplies.
My max speed with PLA and the original 0.6mm nozzle combo was around 40 to 45mm/s if I wanted ‘good’ quality, more like 30 to 40 if I wanted wanted a print that did not require hours of sanding.
With my Aluminium hotend I had to re-calibrate EVERYTHING as the initial prints all failed.
Once done though it was like comparing day and night.
Smooth outer walls, no blobs, no smearing on top surfaces and the dreaded mess when trying to print the sparse infill a bit faster did not happen at all.
With a bit more fine tuning I managed to print PLA in good quality at over 60mm/s…

I guess I could try to salvage a Bambu hotend for the top part and try to make an Aluminium one for my P1S, but can’t be bothered as for the price of a E3D I couldn’t make it myself.
I do wonder though why there isn’t really anyone out there producing Aluminium hotends…
Light, easier to machine and if properly anodised suitable for filled filaments…
Either way a new, a different hotend should always mean calibrating the filament and machine for it.

Hi,

I have just bought one of these. Not installed it yet but have installed the profile. I am having problems in bambu studio. What settings do I change to see faster print times in the slicer?

I am very confused. Help appreciated.

Josh

HI @JoshBear,

I didn’t know there is a machine profile available! where did you find that? :joy:

Update: I just found that instruction page from E3D:

Maybe that answers your questions mostly. As I have written the other text already, I will send it along :wink: I think the values that E3D propose are very conservative.

Before you can increase print speeds, you need to adjust two settings in your filament profiles:

E3D write on their homepage, that the Obxidian nozzle needs lower temperature settings. That is because the thermistor sits opposite the heater, while the stock hotend has them on the same side. So at the same setting, the E3D would achieve a higher temperature at the nozzle. They say, reduce by 10°C. For materials that print very slow like TPU, I have reduced by only 5°C.

Next, you have to identify the maximum throughput for each filament with the Obxidian nozzle.
I use the MaxFlow calibration in Orca-Slicer. I think you will also find models that you can just print instead.
All filaments I have tested so far acheived ~40mm³/s or more. I have set the maximum flow to 35mm³/s for all of them. So for a start you could just use that value too.
You can enter that value in the filament profile in the first tab at the very bottom.

When that is done, you have three options to increase print speeds:
1.) Increase speeds in the speed tab.
2.) increase line width in quality tab → e.g. print walls at 0.63 instead of 0.42mm. So instead of 3 walls you only need 2 walls for the same wall thickness.
3.) increase layer height in quality tab, so you need less layers.

Actually I still print mostly at stock values for maximum quality but way improved consistency and layer adhesion. If you want to print faster, it depends on your model, what is the best value to increase. Increased layer height can worsen overhangs and gives a generally rougher surface. Increased line width will reduce resolution for fine detail. You could also keep outer wall line width the same and only increase other line widths.
I think for small models, there is not much to be gained regarding print times. The print times are mainly governed by layer time and accelerations. For big models, the reduced resolution of 2. and 3. might not be a problem. So here it makes sense to increase values.

Hope that helps.

Thanks. That is amazingly helpful. Much appreciated. In studio I see an option to select the new hotend. I assume I select that as well?

I found configs on the Bambu site as well ObXidian High Flow Hotend | Bambu Lab USA Store

Thanks again
Josh

That is very interesting! I’m using mainly Orca Slicer and I’m not on the latest firmware for several reasons. I have to check if it is available there too. It might solve my issue with insufficient purging.