WSF vs PLA FDM print comparison

Painted WSF on the left, primed PLA on the right.

These are 1/100 scale models of the WW1 Russian Benz-Mgebrov armoured car, a model that I've had printed before, and with all those curved and sloping panels I thought it would make a good comparison test subject. It's about 55mm (2") long.

The one on the left was printed by Shapeways in what they then called White Strong and Flexible, a sintered nylon material. (They've recently changed the names of their materials, though not the materials themselves). I forget precisely how much it cost, somewhere about twelve bucks I think, plus postage.

The one on the right I printed this afternoon, in PLA. It took about an hour and a half, and cost me maybe twenty cents.

Setting aside the issue of cost for the moment, they each have their advantages and disadvantages as models:

  • The WSF model from Shapeways was printed in a single piece; all I had to do was paint it, whereas the PLA model was printed as a set of components that had to be cleaned up and assembled.
  • The detail on the PLA print is much more crisp than on the WSF model. The rivets are actually discrete nubs, where on the WSF print they're really just fairly amorphous bumps, and pretty much had to be painted in to be visible at all.
  • The horizontal surfaces on the PLA print show very marked striations. The print lines are much more marked than on the WSF print. On the other hand, the vertical surfaces are much cleaner and smoother.

I printed the model at an angle to the bed in an attempt to get all those sloping surfaces printing level, or at least, as much as possible. That may have been an error, as horizontal surfaces all showed a lot of banding, and besides which, all the supports required increased the print time quite substantially, not to mention cleanup time. The wheels were printed lying flat, and maybe they would have been better printed standing up — I could live with having to remove supports from around their bottom halves if it meant that the hub detail was rendered more cleanly.

I'm slowly learning a thing or two about what to expect. Now I need to learn a bit more about how to ameliorate the limitations of FDM printing.

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