I did some more speed tests with the same 0.5mm cube:
- The cubes were pulled off the bed while still hot, so they deformed a little.
The 250mm/s one took 0:54" @250mm/s to complete but I think the speed was limited by the acceleration being 2000mm/s^2 and the side of the cube being 20mm. I tried again @350mm/s with acceleration 3000mm/s^2 and it took 0:47" to complete.
I forced the parts off the bed while still hot and they deformed a little. The wall is indeed 0.5mm thick as in the STL. ABS at that thickness is quite flexible.
The maximum feedrate I can safely achieve with the Hadron is 22000mm/min = 366mm/s for a 210mm travel, after that the motors start skipping.
EDIT:As I suspected, the acceleration is limiting the speed for small travel. I designed a similar shape but this time with a longer side of 100mm so that the head can achieve the requested speed and this is the result:
- The bed is covered with ABS juice so that the parts stick firmly to it.
The 150mm/s part printed fine. This proves my DIY extruder's limit lies somewhere between 150mm/s and 200mm/s.
It seems that
to claim high speed records one should have to print objects that allow the print head to reach the claimed speed, otherwise the record would be false.
EDIT 2:Doing a
little math, a 20mm travel can only allow a final speed of :
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v = sqrt( (20mm/s)^2 + 2*3000mm/s^2*10mm = 245.7 mm/s
where:
initial velocity = 20mm/s
acceleration = 3000mm/s^2
travel = 20mm/2 = 10mm
while a 100mm travel allows a final speed of:
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v = sqrt( (20mm/s)^2 + 2*3000mm/s^2*50mm = 548.0 mm/s
We take half of the length available as travel because the head needs to equally decelerate before it reaches the end.
At 3000mm/s^2 the 350mm/s speed is reached after 20.35mm of travel, which means that a minimum length of 40.7mm is needed if we include the necessary deceleration travel. To be sure, an additional length of travel should be added so that the extruder extrudes at that speed for some more time. The best possible test object would span the whole bed; 210mm would allow the head to accelerate, reach 350mm/s final velocity and extrude 169.3mm of plastic @350mm/s feedrate.
Or, a 210mm side will allow a final speed of 794mm/s to be momentarily reached.
Hopefully the above make sence. Here is the STL file, in case someone else wants to measure the performance of his extruder.