More tests of ABS for locomotive wheels

     Quite a few trials to build driver wheels were made using both black PLA and green ABS materials.  Also the raft and support thickness was varied in attempts to obtain good definition of the flange and other wheel features.  Shown in the picture are two complete wheel axle sets and three additional wheels.
    The complete wheel axle sets are all PLA except for one ABS wheel.  On the table top are another PLA wheel and two more ABS wheels.  It takes about 5hr 30min to build one wheel, so the printer has been busy.

    Since flange definition is variable with PLA, ABS seems to achieve better results.  The wheel in center was built with printer Z axis layer size of 0.125mm.  Looking closely you can barely make out the extrusion threads.  Some small gaps are evident.  This wheel was made on a 0.05" raft.  It has good flange definition.  However, separation of the PLA raft delaminated about half the flange layer.  This was due to the extreme stiffness of the PLA raft and support layer.

     The wheel at left was built using 0.25mm printer Z layers.  The extrusion tracks are clearly evident.  This wheel has good flange definition, however, it would require much work to fill the surfaces and make it look solid.  This was printed using standard raft thickness which resulted in a flexible raft and support layer.  This enabled relatively easy removal by bending with fingers.

    After several trials, it was concluded that for ABS the printer Z axis layer thickness should be 0.125mm with a standard PLA raft thickness.  This permits relatively easy removal of the raft due to it's flexibility and leaves little raft or support material to be removed.  Also, surface definition is quite good.  Should this be fabricated in black ABS or painted, or both, most of the small gaps would essentially disappear.  PLA wheels have as good a definition, however, they generally suffer poor flange definition due to material warps.
    Interestingly the axle holes of all wheels are essentially identical and fit the revised axles well.  The PLA axles came out well and require little work to prepare them for assembly.