Dip the Print - surface tension

[mike_biddell]

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).

[mike_biddell]

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).

Forgot to say, that tilting platform could be sold as an optional extra, with jack plug into a socket connection on the Peachy. It would just clip on to the existing tank.

[nka]

The part dosent move, It's "glued" (not really glued but hold there) to the ground and then, the resine float on the top salt water and that's what make the "Z". The only way to do this would be to remove/add salt water and this wont work very well.

[mike_biddell]

The print would be glued to the moveable platform ........... I need to sketch it............ but it would certainly work. I don't think I am explaining this very well, the print is started on the tilting platform i.e. glued to it or a wire insert on the platform. Thus tilting the platform, dips the print beneath the surface of the resin by 2-3 mm. The tilt rod runs up the side of the tank and is operated by a spring loaded solenoid. Laser OFF, turns power off to the solenoid, allowing the spring to release and push the rod to tilt the platform. Laser ON, repowers the solenoid and re-compresses the spring, pulling the rod back.

[Slatye]

Might be easier to just have the servo/solenoid push a piston down into the tank and then lift it back out. Pushing it down obviously displaces water/resin and causes the surface to rise, which has much the same effect as tilting the printing surface but without having to add hinges.

However, I think that the ripples would make either idea impractical. If you wait five minutes before starting each layer so that the surface is perfectly smooth, printing is going to take days.

[mike_biddell]

Slayte............ good idea............ dunno, if the resin is quite viscous, ripples will die very quick, but I suppose the saline could ripple for a bit. However, if it means very good quality prints, I'm not sure I care about the time factor..... just leave it overnight !!!! The solenoid could simply be wired in parallel with the laser, with a spike killing diode obviously. Actually, your idea with a wedge shape, wouldnt cause much of a ripple and it only has to raise the level a millimeter or so, the volume displaced would relatively small. And the whole thing could just clip on the side of the tank. I like your idea better than mine............we'll run with that. I genuinely believe it has legs LOL !!!!!

Form1 tilts the entire tray, so they must have a delay whilst the resin stops slopping around. It's probably pretty viscous, so probably doesn't oscillate for long.

[nka]

IMO, could be as a second step. You finish the print then attach it to the piston and UV lamp to do it.

All-in-one sound great, but not in a short term.

[rylangrayston]

Ah! I really like the wedge idea to for 2 reasons
1 its not submerged
2 it would make no substantial ripples


Have you guys heard of the raft idea (alows the peachy to do at least 4 materials in one print at very low cost)
its talked about here
http://forums.reprap.org/read.php?18...062#msg-249062
and the idea started here
http://blenderartists.org/forum/show...ly-100-dollars!

The raft idea requres a slight up and down motion of the resin between material changes and so the there is alot of valuable ideas there too.
but i havent seen this wedge one there yet so hope you post it on reprap !


What we have being doing so far is simply printing so slow that there is alwase a layer of wet resin on top the print. All the actual hardening actually happens below a very very thin layer of liquid resin over the wall of the print. I think the dipping combined with a very thick resin would actually get you Faster prints.

[mike_biddell]

Rylan.... very interesting thread........... didn't realise there was any dialogue going on in the reprap forum, so will now start mooching there too!!!!

[mike_biddell]

Rylan.... very interesting thread........... didn't realise there was any dialogue going on in the reprap forum, so will now start mooching there too!!!!

Just realised a solenoid probably wouldnt work, because of the length of travel required. Probably have to be a screw drive.