How fast can your hotend print?
Why 3D Printing Stack Exchange recommends it
3D Printing Stack Exchange answerers link it when explaining why high print speeds cause under-extrusion and how hotend flow limits and temperature interact.
Recommended by 2 people across 2 different months, 2020 to 2021.
What it is
CNC Kitchen shows how to benchmark the maximum volumetric flow rate of a 3D printer hotend by extruding filament at increasing speeds and weighing or measuring the result. It also covers when higher printing temperatures are needed, for example with a hardened steel nozzle. The video is backed by a written article and references to nozzle and melting research.
What people said
Recommends fred_dot_u · 2020-03 · 3D Printing Stack Exchange · on “Casual under-extruding on Ender 3 (don't know what to do anymore!)”
You may have a problem with the nozzle heat setting being too low for the flow rate, which is directly related to the travel speed. As a background, when you're printing fast, the stepper motor driving the extruder has to move filament more quickly. That's obvious, but what is overlooked often is that the heater may not be able to move heat quickly enough to keep up with the filament. Consider increasing your hot end temperature by five degree steps until you observe that the under-extrusion is resolved. Some colors and brands of filament require adjustment in hot end temperatures. I'm currently printing with silk-like PLA. The filament I usually use prints at 210°C while it was necessary to
Recommends octopus8 · 2021-01 · 3D Printing Stack Exchange · on “Ideas to tune for 300 % speed”
Changing "Flow" will affect whole print. So even if it helped for the middle part (I doubt), the next it would ruin the print on sides by overextrusion. However: if sides are printed ok, then why the middle couldn't? Because walls are printed slower? Indeed, the under-extrusion may quickly rise along with speed because of plastic deformation between extruder gears under pressure and slight slipping, which actually increases with speed. The video " How fast can your hotend print? [this video] " presents experiment on this phenomena and its outcomes. Then we go into master question: 300% of what? Turning the speed knob during print will override all considerations that slicer took into account duri
Cites FarO · 2020-05 · 3D Printing Stack Exchange · on “How to fix bad extrusion that's likely caused by high pressure in the nozzle”
I think you are pushing filament too fast. Let's go back to the basics: my hotend (old Ubis, ceramic) and extruder can push PLA at 230°C at max 80 mm/s * 0.5 mm line width * 0.2 mm layer height = 8 mm 3 /s. At this speed it doesn't extrude very well, there is too much back pressure (see also ). That extrusion speed means (I have 3 mm filament) 1.13 mm/s of filament speed (8 mm 3 / 1.5 2 / pi). You have 0.3 mm nozzle and you print colder, both of which cause more resistance to the flow. If 8 mm 3 /s is my absolute max, yours should be about 8 * 9/16 (ratio of the nozzle surfaces) = 4.5 mm 3 /s (really the max). Considering the different print temperature, I would start limit to 3.5 mm 3 /s, w
Cites FarO · 2021-01 · 3D Printing Stack Exchange · on “Is a slower outer perimeter speed still meaningful?”
In the past we had printers with poor mechanics and with primitive software algorithms, therefore we used to print inner perimeters faster than the outermost one. See for example (generic, found online): [LINK] However now we have pressure/linear advance which reduces extra oozing/extrusion in corners or areas with variable speed, and in Klipper we also have resonance compensation [LINK] which takes care of imperfect mechanics allowing printers to be pushed to higher acceleration without visible artifacts (in my case from 2000 to 6000 mm/s^2), see (generic) photo: [LINK] However printing slower has a clear disadvantage: E steps calibration is speed dependent with more filament being pushed o
Cites FarO · 2021-02 · 3D Printing Stack Exchange · on “Increasing hotend temperature to compensate for increased filament throughput”
No there is no rule of thumb as far as I know and no, it's not obvious for someone with skills in thermodynamics. I know that if you want extreme speeds you need extreme overtemperatures, for example Annex Engineering uses ABS at 290 °C (about 50-60 °C overtemperature) with a Mosquito Magnum (rated at about 40 mm^3/s) to reach 60 mm^3/s: Still, you need to find the optimal value based on your hotend, your extruder, your nozzle size and target flow rate. You may do static tests as explained here: There cannot be a rule for such a complex behaviour. Also, be aware that Annex Engineering uses 23 000 mm/s^2 (not a typo, really 23 thousand) as acceleration, therefore their printing head moves at