Dip the Print - surface tension

[masterada]

Have you guys heard of the raft idea (alows the peachy to do at least 4 materials in one print at very low cost)

CMYK - and we are almost there

[Pete]

I've been doing some tests with a pump I've got and written about it in the drip governor thread. The pump in and out test I just did could well be a solution to this as well. http://3dprintboard.com/showthread.p...rst-hack/page5

[Aztecphoenix]

It occurs to me, that since we are switching the laser on and off successfully, that signal could also operate a small solenoid to dip the print. So that laser OFF dips the print 2 - 3 mm and then laser ON returns the print to its former position. The solenoid would move a print platform down and then back up, in synchronisation with the laser (there's probably enough power with the existing 10 amp FET, to use the same output FET, so no extra components required). This would allow each layer to be well exposed before doing the next and reduce a lot of the calibration problems. So the laser would make maybe 10 transits of the current z, laser OFF (solenoid OFF) then dips the print, laser ON (solenoid ON) then returns the print to its former position. The laser will obviously have to wait for any ripples to die down, before carrying on. The solenoid would obviously be positioned on the outside of the tank and could just tilt the platform via a plastic lever, to allow wetting of the print surface. This is quite easy to design mechanically and would be analogous to the form1 tilting tray (used to tear the current layer off).

I've been thinking about this problem for a VERY long time now and I think I may have come up with a simpler solution, it seems to me that the easiest way to deal with the surface tension problem is to simply displace the water in between layers, so on the side of your build tank you have a vertical pipe with an opening at the bottom, in the pipe you have a piston hooked up to your solenoid, the piston is set so that the area inside the pipe while the solenoid to the solenoid at full travel has the same volume as 1mm thick layer of your build tank, then as each layer finishes being printed the piston extends displacing exactly 1mm of water and then resets bringing the water back to its normal height to be raised by the drips to the next layer print by having the opening at the bottom of the pipe it should eliminate the rippling in the build tank and just cause the water to move up and down once every layer, if you want to take extra precaution, make the pipe double walled to prevent any vibrations from the solenoid from disturbing the water.