Delta Robot 3D Printer. Sounds cool doesn't it?

Alright, I've been meaning to post an update for a while now, I was just hoping to have finished the rebuild by now... Anyway, I have been working on a UV/Visible cure resin 3D printer using a 405nm laser. I started off thinking if I could mix a Delta Robot and a resin printer in one it would be ultra double awesome. While it was pretty darn cool and fun to build, it just didn't work great.

I first started with a dynamixel servo based delta robot design thinking they should have a decent resolution.



Then after I built it, I found that was not the case, at least for 3D printing purposes. Also the controller started resetting every couple of moves so I probably fried it somehow.

At that point I did some more research and found some people working on a delta robot for use as a reprap printer. Following their design I used steppers and gears. The gear ratio was chosen mainly for what would be easy to cut on the taig mill. All worked out on paper it looked like it would have a decent printing resolution. My brother drew it up and we got to work cutting it.

We made the Z axis pretty much out of scraps and it didn't work the best. (linear servo... what was I thinking?) It was good enough to test the theory though.

After assembly and mangling the reprap firmware into a usable shape for a delta robot we were ready to go.



Yeah, it printed an awesome lump! It was supposed to be a small hexagon.

So, what went wrong? First off I think that shooting a laser at a shiny aluminum plate is going to make the laser reflect all over... Yup, also I think dye needs to be added to the resin to help with the reflections and diffraction. The delta robot worked alright but I just didn't feel it would make the best quality prints. There was a little too much backlash and the inverse kinematics is not my thing.

So now we have redesigned, again, but this time back to the tried and true (but boring) Cartesian robot. Here is the X and Y axis, still working on the Z axis redesign but hopefully soon we will have more acrylic lumps cool 3D stuff printed.

Cutting the parts for the robot arm.

 I just got my Taig mill a few months ago and I am still learning a lot about machining (mostly how to break small end mills) and one of the reasons for getting the mill was to make robots with my 5 and 7 year old boys. So, we decided to start with a robot arm and I found drawings for one on Thingiverse.com I started cutting it out of 1/8 inch aluminum and realized pretty quickly that the time spent while the CNC mill cuts out the parts is spent removing the chips and spraying cutting fluid or else the aluminum welds to the end mill bit. After sitting for a couple of hours doing this I did some research and found that it wasn't that hard to setup a flood coolant system for the Taig mill. This lead me and my brother to build an enclosure to keep most of the coolant from flying everywhere and a tub, drain and filter system to get the coolant back to the sump. After a few hours of building and lots of on the fly re-engineering we ended up with this.

 

There are a few things I would like to change about it and a few things I will just live with but overall I am pretty happy with it. I had a pretty good idea of how to build it but as things went together I saw some problems with the design and just did quick things to get it working. I think I will at some point make a removable shield that actually mounts to the x-axis stepper mount and take down the table mounted shield on the right side.

I had seen a manifold to mount the coolant hose to the mill head at cnczone.com and so made something like that. It was my first real part that I made manually with the mill. It was pretty fun but I will probably do most things with the CNC.

So this is the difference between cutting without flood coolant and cutting with.

The Robot Arm

 Just a quick post to have something to start with. Here is the new robot arm, just got it moving. It is based off of http://www.thingiverse.com/thing:2433 by jjshortcut. It is made from 1/8 inch aluminum cut out on my Taig CNC Mill. Halfway through cutting out the parts I had to stop and build an enclosure and flood coolant system for the mill but that's another post... It is controlled (currently) by a Wii Nunchuck connected to an Arduino which controls a Pololu Mini Maestro 12 servo controller.