For one of my projects, in partnership with a couple of mates, we decided that the best way to make the prototypes we needed was to get an affordable 3D printer. So I did a bit of searching and found that the machine from here - www.pp3dp.com would be good enough to do the job. So I sold a couple of things to pay for it and got it shortly before the recent round-Aus trip.
So far I've mainly just been printing various things for fun and to learn how it works and its limitations.
The attached pics show mine, the ones below are from http://www.thingiverse.com and that's where I get all my files from so far.
In the attached pics, the first one is of the unit as I was connecting it up to the laptop. It doesn't have the print table on it yet nor the hollow tube that guides the plastic from the roll to the print head.
The second one is the first print I did and that's a calibration run. It's used to refine the accuracy of the machine; you print it out then make some measurement, feed them into the software and it adjusts subsequent prints.
The third one is of the Star Trek Enterprise, a good friend of mine is a ST nut so I made one for her. The shape is pretty cool so I decided to make a bigger one for myself (okay I'm a sci-fi nerd) and to make it bigger I turned the section you see in that photo 45° so it went from corner to corner. Because of size of the print I was able to find out that with large ones like that the heating/cooling effect is enough to cause stress cracking on the edges as the entire thing cools down. It's a bit of a pain but it easily fixed with some acetone & ABS plastic scraps to make a kind of plastic big to fill the cracks. It's also really slow; the big Enterprise saucer section for me took over five hours to print. Smaller stuff can take less than twenty minutes though.
So just linking to the Thingiverse site to show some of the stuff I've made ....
That's a three-piece rocket I made. With a little fiddling you could make it to take a model rocket engine. But there's other models on Thingiverse that already can take engines so no real need.
That's a screw-on adaptor for a water rocket. You attach an air hose to pump pressure in and away you go.
Rotary key rings. I've only got a roll of white plastic so that's the only colour I can print in for now. But there's a reasonable range of other colours now.
A model rotary, to show how they work.
A funny cube with geared corners.
Oval gears that mesh together surprisingly well. The whole thing is pretty floppy though.
To print stuff, it takes the plastic from the roll into the print head, melts it, then squirts it out a hole that's about 0.2mm diameter and lays down about that thickness of plastic, layer by layer to make up the object. So because there's only a very small amount being added each time, it takes a while for it all to happen.
Here's a video of it printing the calibration piece.
Because of the limitations of the way it extrudes the plastic, it needs to print a support for anything that would otherwise be hanging in mid-air. The angle that starts to happen at is adjustable in the printer software and I haven't played with it much yet. You can see a bit of it in the third pic. To save plastic and to help avoid the problem of thermal deformation as it cools, the software defaults to making almost all the interior of the piece to be filled with a matrix of thin plastic. It looks pretty weak but once it's completed the objects feel pretty strong. Again the amount of filling is adjustable. If you look at the fourth attached pic you can see a half-finished Enterprise and see what the internal matrix looks like. (Snr wanted to use the powerpoint the printer was plugged into, so he just pulled the plug out about two hours into that print.)
The printer software can't edit or change the objects at all, only change the orientation of how they sit on the print table, though it can scale the object up/down as much as you like - within the 130mm x 130mm limit of the table though of course. The orientation is important as if you are printing multiple objects and the edges are too close to the sides of the table, the edges can suffer from differential cooling and start to lift up, causing a bent edge there. Everything that's printed gets a little 'raft', as they call it, to start being printed on so it has a nice, flat surface. But again if the object is too big or too close to the edges the raft starts to lift up and I've lost a few prints that way. The table is heated to 100° to minimise this but it still happens unfortunately. So it's often better to break down the bigger objects into smaller pieces. The raft thingy just peels away like it was attached with velcro once you lever the object off the table.
Another problem is if you're just printing one small object, then it can overheat from the print nozzle sitting near the one spot too long and you end up with a bit of a melty mess. So the trick there is to print four or more small objects so the print head keeps moving around between them and so they each have time to cool.
Anyway it's a handy little thing to have. If anyone wants anything from Thingiverse printed up it'll be $0.60 per gram of plastic (minimum $10), the print software tells me in advance how much plastic it'll use. You can also design your own stuff if you like, the printer uses *.STL format files and there's a few CAD programs out there that can save in it. I'm still pretty sad with 3D Autocad but am slowly getting to the crappy stage, I hope to be below average soon.