When moving the Z-axis, noise is produced, partly by the motor, partly by friction. Our Z-axis leadscrew is not completely straight. To remedy this problem we designed and 3D-printed a construction which we mounted and the lowest possible part of the Z-axis extrusion. See picture. This reduces the noise during the up-movement. Down-movement still generates too much noise in our case (but will keep the seedloving birds away?).
A motor damper has been suggested already.
Any other suggestions anyone?