Quote Originally Posted by Hugues View Post
Cured resin being the future or not, i don't know, but it's hard to imagine substantial gain in speed and surface smoothness with FDM. Seems we have reached a plateau, at least with the typical extruder. Having to draw a layer line by line is a hard constraint. If you want to reduce the extrusion width to improve smoothness, it takes you so much more time to draw one layer, then you have to produce more layers per inch, again more time So we're talking orders of magnitude slower. I have my FDM printer for over a year now, it can do 100 microns layer, but i never really bother to print at that level because it's so much slower and you still see the layers anyway. So all my parts go out at 200 microns. ANd 100 microns is pretty much the accuracy of most if not all the new FDM printers that were launched in the past year, no substantial improvement on that side.
I think you're right in that we aren't going to see much of an increase in FDM speed. In fact, I don't think we're going to see much of an increase in the speed of any of the current technologies. By definition, additive manufacturing means building an object one layer at a time. The only ways to increase speed are to reduce the number of layers, invent a material which lends itself to faster layer creation, or find a way to create more than one layer at a time.

It's also important to point out the difference between resolution and accuracy. Resolution typically means layer height. Accuracy typically means X/Y variance – how accurately each layer is being laid down on the X and Y planes. With FDM, accuracy is a huge factor. I've seen a personal FDM printer print at 20 microns, but the layers were still plainly visible. I've also seen a Stratasys Mojo print at 178 microns and the layers were barely noticeable. That's how big a difference X/Y variance can make. A Stratasys FDM printer produces objects of such high quality, they can be used as injection molding prototypes. It's still not as good as SLA, which can produce layers that are both invisible and perfectly smooth to touch, but it's much better than personal FDM.

I'm curious, what kind of resin are you going to use for a functional bike part?