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bernhardkubicek

Acceleration!=Deceleration for repraps.

If we had independent acceleration/deceleration on a reprap, how big would the effect be?

The most "difficult" to move axis would need a weight of mass "m" to overcome friction when tilted 90°.
The force f=m*g. This force shall equal the breaking acceleration of the axis moving weight M (if Stiction would equal friction): f=M*a, a being the acceleration.

Hence a= 9800*m/M  mm/sec^2.

For an ultimaker m would be 0.7kg while M would be 0.5 kg approximatly. Hence if you would decelerate with 13700 mm/sec^2 the motors would feel no torque.

A mendel is reported to have the axis move if its tilted by 25°.
In this case f=a*M=g*M*Cos(alpha).
The acceleration hence is a =9800*cos(holdingangle)
For a mendel thats approx 8800mm/sec.

Hence, not considering rotational mass of axis and motor, and ignoring structural vibrations, the breaking acceleration could be double than the current movement accelerations of ~6000mm/sec^2.
Reposted byreprap reprap

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