On 04.04.17 10:21, andy pugh wrote: > On 4 April 2017 at 07:51, Gregg Eshelman <g_ala...@yahoo.com> wrote: > > I wonder if they've heard about lost PLA casting? > > This is a 13kg casting in iron, that would be 2kg of PLA, about £40. > Though i guess you would use a low fill density, so it wouldn't be > quite that much.
+1 The reason that lost foam works well is the large amount of air and small amount of plastic. The gush of flame from the riser(s) is limited, at least on smaller castings, resistance to metal flow is negligible, and heat loss to plastic fusion is minimal. To replicate that, I figure that 3D printing would have to print a thin solid skin to exclude the mould sand, and a very open internal weave, sufficient to support the external walls, but minimising the height of the flames at the vents, as well as the obstruction to metal flow. (The last is doubtless a bit less critical with CI than Al, so long as the risers and vents can vent the gas pressure, to avoid molten metal erupting back out while pouring.) A mould cavity filled with 2 kg of solid plastic fuel does not bear contemplation. If the printed volume were as much as 10% plastic, I'd experiment with a quite small one first - for the purpose of surviving the experience. Erik ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
