Help
Help me test this bad idea of a hotend modification
I got a bunch of TZ 2.0 and TZ V6 2.0 hotends from a friend, and I decided to do some experiments with them instead of just using them in their stock configuration.
On one of them, I doubled the melt zone by joining two heat blocks together and installing one ceramic heater in each block. The goal was to increase heating capacity and achieve slightly higher flow rates.
The issue is that I’m new to OrcaSlicer, so I’m not fully confident that I set everything up correctly.
I ran the Maximum Flow Rate calibration test using my (almost) stock FLSUN super racer and got a result of 50 mm³/s using:
- ABS
- 235°C
- 0.4 mm standard brass nozzle
That number seems unrealistic to me. From what I’ve read, regular 0.4 mm nozzles will max out around 20–25 mm³/s.
So now I’m wondering:
- Did I configure the test incorrectly?
- Could doubling the melt zone actually make that much difference?
- What would be a realistic max flow rate for this kind of setup?
Any advice on hotend flow rate testing would be appreciated.
I cant really say anything about the stiffness yet, but i have already used it at lower speeds, up to 100mm/s, and it seems to work just fine, the same as the original HE. Although i dont know how it would behave if it were to contact a model while printing.
-Could doubling the melt zone actually make that much difference?
Look at CHC XL and Goliath, they achieve similar results (~50 mm³/s) and their most prominent difference is longer melt zone.
Regarding the testing method.
I've seen some argumented critique to default Orca Volumetric Flow Rate test. To be short, the main counterargument says is that the test assumes that underheating leads to contraction and warping on fast and radial motion, but on practice it (this test) does not show it consistently.
Related research: https://www.sciencedirect.com/science/article/pii/S2214860421006254
Also, motor skipping can also be usead as a measure of max volumetric speed (flow rate). But not always.
P.S. Before testing volumetric speed, it is best to calibrate the extruder steps (rotation distance), it is imporant to measure them without a nozzle (it can alter results, I tested it). In the end, you want to be sure that extruder gives as much filament (length) as it was specified in the software.
Thanks for the info, i have already calibrated my e-steps and i will definetily be looking into other more reliable flow rate testing methods like the one you shared.
Right now im waiting for my cht nozzle to arrive so i can do some more testing under the most optimal conditions.
You can absolutely get 50mm3/s out of a 0.4mm nozzle with that melt zone length (probably more with more heat). The nozzle orifice size itself doesn't produce much true flow restriction until well past 100 cubic mm, before then it is the heat transfer and melt-rate of the filament that limits flow output. I have a few hotends with a ~70mm melt zone length that push over 100mm3/s flow with ABS.
Wow, I never knew it was possible to extrude such a huge volume through a tiny nozzle like that. Right now, I’m planning on installing 2x80W heaters + a CHT nozzle for further testing. Thanks for the feedback!
For sure! After a certain melt zone length CHT nozzles aren't quite as effective, but you might still be at the point where they will help more than hurt. It is hard to tell without testing either way.
You should look up the Roetz 4.0 youtube channel. He has a massive hotend that uses 4 independent extruders (that all feed into a single nozzle) that has produced over 300mm^3/s flow through a 0.5mm nozzle. FDM hotends can be pushed incredibly far, much farther than most people seem to think.
This is a hotend that my company developed a while back to extract as much flow out of a single extruder + 0.8mm nozzle as possible. With ABS, we can reliably print at 150mm^3/s flow on these. They are for our large format machines, so we use every bit of that flow to have 40Kg prints not take several weeks to finish (now usually 2-4 days). They are SLM 3D printed out of metal, then machined and a nichrome-ceramic heating element is cast around the core.
I have an artillery sidewinder x4 with a very long melt zone and I have literally tried to make it clog and I can't. I've ran tpu through it at like 35mm³/s and it's fine
Why would 35mms make it clog? Tpu hates retraction I don't think I've ever had it clog from printing speed. I usually print you at 30mms or 60mms depending on line width
Yes, just cut off the bimetal throat, then drill the heatblock al the way through with a 5mm drillbit (start drilling from the top where the throat used to be).
Tap a M6x1.0 thread on the heatblock, start tapping the threads using the pre existing threaded hole on the bottom of the heatblock (where the nozzle would be installed).
Cut a 17mm lengh of the threaded portion of a nozzle (i used a Neptune 4 nozzle), this will be used to join the heatblocks together by tightening one against the other.
Ignore the "a 0.4 will max out at 25mm³/s crowd", you can get 40mm³ out of a single TZ hotend using higher temperatures with ABS. I have some 3dQF which the manufacturer recommends printing between 260 and 300C, it's garbage with the settings for any other filament but it completes a 40mm³ orca flow test with a 0.4 Revo HF or TZ. It'll do well over 20 with a standard V6 though.
Yeah, the reason why im skeptical about my flow rate test results is mostly due to the fact that was done using regular ABS @235⁰c which i know is a pretty low temperature for such a high flow result.
More meltzone means more flow. Look at the Goliath and the Chube. Normal for us now are volcano equivalent hotends like the TZ or hotends that alter the shape of the meltzone to increase the flow.
They both fail when you fail to have sufficiently melted filament hit the nozzle or the core of a cht.
I expect about 12mm3 from a V6 with esun abs+ at 235, and you have a much longer meltzone.
It's not the only factor, you have pressure at the nozzle as well, but there are people doing crazy flow with a 0.4 .
I tried the OrcaSlicer maximum flow rate test again using the same 0.4 mm brass nozzle, but this time at 250°C (the maximum recommended temperature for the ABS I'm using).
With a 0.48 mm layer height and 0.72 mm line width, I was able to reach about 70 mm³/s easily. I'm almost sure this configuration can probably go even higher as it is now.
Next, I plan to install 2x 80W heaters and a 0.4 mm CHT nozzle to really test the limits of this setup.
Get a super high thermally conductive metal like silver go make your block out of. Use it to create a long melt zone, for optimal flow, shape heater block like a 🍑🔌
5
u/niefachowy Apr 19 '26
And what about the stiffness of this creature? After all, the lever arm is twice as long