Impact of hollow axles

    In an earlier entry it was postulated that hollow design for the axles and perhaps other parts would result in faster printing.  The left hand axle shown is solid while the right hand one is hollow per the design.  The results of hollowing for the rather thin wall of 0.05" is splitting of the wall at the point where the Axon conversion software reverses from clockwise to counterclockwise following of the wall.  Both axles were printed upright as shown.  The end portions of the right hand model have a tapered fill inside that gradually closes the hollow so that the end caps are solid.  At some thickness of the taper the split discontinues, consequently the wall thickness is likely the real issue.  Evidently 0.05" is too little wall thickness and needs to be greater.  The solid axle at the left has a 50% fill factor selected during the Axon software conversion of the design and is actually not fully solid either.  However, the walls are much stronger due to the presence of fill material (also ABS) that provide reinforcement for the walls.