Laser 3D Printer - Stereolithography at Home

It's working! It is a bit of a work in progress still but so far it is working pretty well. This is mainly an experiment which started as a Delta Robot Stereolithography Printer but ended as a more traditional Cartesian Stereolithography Printer. For how it was built, check out the instructable here.

"I'll be honest, we're throwing science at the walls here to see what sticks. No idea what it'll do." - Cave Johnson

Stereolithography (SL or SLA from Stereolithography Apparatus) is an additive manufacturing process using a vat of liquid UV-curable photopolymer "resin" and a UV laser to build parts one layer at a time. On each layer, the laser beam traces a cross-section pattern of the part onto the surface of the liquid resin. Exposure to the UV laser light cures, solidifies the pattern traced on the resin and adheres it to the layer below.

I have wanted a 3D Printer for a while now and there are some very reasonably priced kits available like the Makerbot, Ultimaker and the RepRap project. I could have just bought a kit and started printing things but at the time I had not seen great resolution or print quality from those. I started looking around at the other 3D printing technologies and found SLA made some amazing quality prints, so I decided to try making my own. Since I started this a while back those projects have come a long way and they can make some beautiful prints now. There are also people working on a UV resin and DLP projector 3D printer which is showing promise. 

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.

Brass Sign

Here is a video of cutting a brass sign for a Christmas present. It was the first time I cut brass on the Taig mill so I went pretty slow. The video has most of the cutting sped up 4x so it is a little more interesting. Merry Christmas Brian and Amy!

 The first picture is what I was given for the layout. The next two are output from the design I made in VCarve Pro.  

To hold the sign in place during the through cut I used the Tabs feature in VCarve Pro. Then I used a hacksaw blade to cut the tabs and a file to remove the rest of the tab.

CNC Router

 Here is my CNC Router that I built a few years ago based on plans from buildyourcnc.com. I was asked to make a sign for a friend and didn't like the router letter templates available so after doing a little research on the internet I found that you could build a CNC Router. It was a fun project to build and I never get tired of watching it move. Anyway, the sign may have taken a bit longer but it looked really good when it was done.

 The limit switches still aren't hooked up but I did make sure the E-Stop button works. I really like the Big Red Button I found at Gateway Electronics, it just makes it look more like a real machine for some reason. I also got the transformer for the power supply there.

I went with the Hobby CNC controller kit bundle which was very affordable but you have to solder it yourself and build the power supply. I am glad I did because this was my first big electronics project and it has been another hobby I have enjoyed ever since.

It is currently staying at the St. Louis Hackerspace called Arch Reactor. The video of it below is from the Arch Reactor open house at the old location and has some other cool stuff from there on it too.

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.