yea I'm fast coming to the conclusion that this machine wont do for my jewellery work unless I make jewellery specifically for this kind of media IE big and chunky. http://www.mousejeweller.co.uk
I will try the print more than one to see if that solves the issue but it looks like this machine will be doing models rather than jewellery.
as for your questions. its about 20mm tall and the back of the skull is orientated to the bed...
The sample print you showed is not typical of the quality that you can expect from a UM2 - it's a bad print, probably just resulting from using the wrong settings. You'll need to take the time to learn how to get the best out of it. I wouldn't just give up on it, until you've invested some time to learn the tool, and figured out exactly what its strengths and weaknesses are.
You may get better results using a smaller nozzle tip in order to get the finest detail, but you'd need to talk to UM support about whether they can help you with that, as I don't think it's as easy to build your own nozzles on a UM2.
Also, even for fine jewelry work, a 0.02mm layer height setting is probably overkill. The X-Y resolution of the printer for fine detail is going to be limited to the size of the nozzle (0.4mm standard). There are some things you can do to reduce this a bit via software (such as telling Cura that you have a smaller nozzle than you really do - maybe down to about 0.3mm) and the positional accuracy of the head is much finer than that - but when you're extruding a continuous 0.4mm diameter bead, that's going to determine the tightest radius of curvature on fine details. There's not really a lot of advantage in setting the Z resolution 20 times finer than that. The layers should start to become invisible by about 0.06mm.
Are you intending to print PLA, and then use that for lost wax casting? If you can use ABS or some other plastics, then you have the option to vapor polish the print - but those materials don't burn out as cleanly, or un-obnoxiously as PLA.
for something like this we would be using a cold cast media to get the injection moulds. so just getting the model to a good surface finish is all that's needed.
BUT as you say I don't think it will get the quality I need. HOWEVER this isn't such a bad thing as I can now make miniatures with this instead which means selling modelled avatars and such is defiantly a money spinner. ill work up the money to get my self an envisiontec and go from there
in the mean time heres some more prints
I'm going to assume that the *back* of the scull was printed first (on the bottom). YOu have some *serious* unsupported overhang there. That's difficult to print. For a bust or skull you probably want to print the flattest possible surface down. And the bottom of things printed often looks worse so for this skull I would consider printing in the "normal" up/down position.
The rest of that skull has tons of bumps on it - it looks like crap. Try cutting the print speed in half to see if those go away:
See this photo of this pumpkin with similar (maybe?) bumps:
http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/?p=24010
If you are using these for cold casting you can use sandpaper or metal files to remove bumps, and bondo to fill in gaps. You can use a solvent to hide the layers although like Illuminarti says, that's much easier with ABS.
Check out this nice finished print:
http://umforum.ultimaker.com/index.php?/topic/467-post-your-latest-print/?p=18661
posting #541
Scroll through all the prints in there - some of them are amazing and you can't tell they were 3d printed
It takes a few weeks of printing and experimenting and reading the forum to get your cura settings dialed in for your particular needs. You can certainly do much better than that skull.
So after much dicking around the machine is starting to play along. setting cura up to have the fans at full power and adding my own desk fan into the mix has improved the print quality at 200c and 210c.
Along with printing at 40% - 60% speed at 95mm/s and having 15s layer cooling time with the default 20% infill.
AND FINALY
having the printed object at around 45degrees to the print bed. has also made a difference. see pics below print is around 4cm tall and printed at 0.06 layer. the top section issues are obviously to do with too much heat in a small area which I'm not sure how to solve ?
while the layers are visible this was taken with a macro SLR, but to the naked eye it doesn't look too bad and I guess with finishing it might look fairly nice... here's hoping
also here's another post with a much smaller print of the same object with the same settings as mentioned above just at 1.5 cm tall (that's a 5p piece its standing on) ... the surface is bad but the print looks good in hand and gives me hope that small charms aren't out of the question
I do still question if this machine really can print 0.02 layered prints without causing issues. but I'm sure more fiddling will get results...
maybe printing 2 at once will help
Printing 2 at once will help with the top but you may get stringing. But to print 2 make sure you set your "gantry height" in machine settings to 0. Verify that it isn't printing one at a time in slice view.
To reduce stringing keep things cool and print possibly even slower. For example 190C at 30mm/sec is about right with this blue PLA filament on the UM2.
You might also want to turn off the heated bed and use the blue tape on cold glass. You might have to relevel with the blue tape adding a small thickness. But try without leveling first as the UM2 tends to just have it's extruder motor do some "clicking" if the head is too close. No big deal.
Finally when things are dialed in print a real big version! It will probably take 10 hours but it will be worth it!
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illuminarti 18
What was the orientation of the print on the bed... ? It looks like you probably need more time for the layers to cool, before another layer gets put down on top, but it's a bit hard to tell exactly what's going on. It could be the opposite, that it's slowing down too much. It's also hard to get a sense of scale... how big is the part?
Sterelithography or SLS printers are normally better suited to the very finest detail work. Filament deposition isn't really the best technology for very fine detailed parts like small jewelry, so you'll need to take some time to learn how to get the best out of it. Layer cooling is a big challenge - you may need to print more than one thing at once, so that there's sufficient cooling time; slowing down the print only helps so much, before the head is going so slowly that it heats up the already printed plastic, and makes the problem worse. However, among similar printers, I'd say that the UM2 is probably the best choice for detailed work, as it has relatively good retraction control from what I've seen, and makes for precise prints.
Much of the art of 3D printing is learning the settings that work best. Small fine pieces are very challenging, so start with slightly larger, simpler shapes, and work your way up. Enable the full settings in Cura, and study the options, and experiment. Keep good notes about what works and what doesn't.
Eventually, for the most challenging prints you might want to switch to another slicer that offers the finest grain controls, and allows you to tweak everything. But to begin with, stick with Cura, and learn the basics.
Happy printing!! I think you'll get some great results given time... and keep posting, and we'll keep helping you get there :-)
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