Re: Another Shapeways report

soolinehistory <destorzek@...>

--- In STMFC@..., "pullmanboss" <pullmanboss@...> wrote:

Time to clear up some misconceptions. There are two inkjet-type heads mounted back to back. One contains body material, the other contains support material, in this case wax. Each head is capable of dispensing its material onto any pixel in a layer in the same pass. Same resolution, same layer thickness... But where there was wax, those tiny marbles that were in contact with the wax will have oozed out from the surface, leaving a rough patch...
Thanks for the more detailed explanation, Tom. So, while the resolution is the same, the effect on surface finish is certainly detrimental. Which leads me to conclude that Fused Deposition Modeling (FDM) isn't the right process for mechanical parts like brake cylinders and valves which by their very nature are going to have overhangs somewhere.

I wonder about SLA? From photos of parts like dental crowns it appears that can build an overhang, so long as it is continuous with all the fused material on a given layer, to a point... the Asiga web page makes a claim that their software automatically calculates where "support structures" are needed. The problem is, these support structures are then one with the finished part, and have to be cut away by hand, maybe just a sprue nipper job, maybe much worse.

As to the surface finish on the part in my photo relative to everyone else's, keep in mind my triple valve is but a fraction of the size of what anyone else has posted photos of, so the magnification is much higher.


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