The platform probably never reached top speed, because the moves were too short.glx51mm wrote:18000 mm/min with low acceleration
At 900 mm/s², the platform requires 50 mm to reach 18000 mm/min = 300 mm/s along a straight segment. However, it must also decelerate at the end of that segment, so segments shorter than 100 mm won't allow full speed; it hits full speed only in the short section between the 50 mm at each end.
So, for a 20 mm calibration cube, the maximum speed in the middle of each side will be only 134 mm/s = 8000 mm/min and the average will be much lower. A more complex shape with no long straight lines (like, say, the Alien monster) will run at a small fraction of the maximum possible speed.
That's why support structures cause so much trouble: the machine can approach maximum speed only when printing those long straight segments.
Basically, when you set the acceleration low enough to remove corner ripples, the maximum speed setting won't have much effect: the machine can't get there from a standing start.
For a constant top speed, the acceleration and distance have an inverse relationship: ten times more acceleration reduces the distance by a factor of 10. At a constant acceleration, however, reducing the top speed by a factor of 10 reduces the distance by only a factor of √10 = 3.2, which explains why tinkering with acceleration has much more effect.
Because the force applied to the machinery is proportional to the acceleration, you get a bigger payoff from limiting acceleration, not velocity.
Some path planners allow speed blending around corners by trading positional accuracy for smooth transitions, but that's a whole 'nother topic... [grin]