3:1 Lego minifigure cut on CNC

Woodlake

I have just finished building a homemade cnc machine and decided I would cut my teeth on a lego minifigure. Those of you who have a cnc will appreciate that there is quite a steep initial learning curve due to the fact that you need to get a handle on three separate pieces of software to get the result you want:
Firstly, you need to draw/model the item you want to cut (I could have used a model from the google warehouse, but sketchup suffers from faceting due to the fact that it uses straight lines to create it's curves. Seeing as I wanted to have a larger figure meant that these facets would probably be visible).

I ended up modelling the figure in Rhino, which I am also new too. It took a little time, but was relatively painless. The best thing about Rhino is that it is a nurbs modeller, meaning that it is resolution independent and a model can be scaled up to any size without any ill effects .

Here is a screen grab of the model in Rhino:


Once I had the model, I went about "slicing" it. The reason being that I only have limited length milling bits. The idea is that you slice your model into pieces the depth of the material you are cutting out of - in my case 12mm (1/2") mdf. I then arranged these into a 200mmx200mm (8"x8") area.

The second piece of software you need is to produce the g-code to send to the CNC. Since I already have Rhino I invested in a 3rd party add on (RhinoCam) to take care of this. Again fairly painless, but just took some time to go through the steps. I did 3 stages of cutting - 2D profiling, 3D roughing and 3D finishing. Probably not the best idea to start with a 3d model, but there's nothing like throwing yourself in the deep end!

The last pices of software you need is one which reads the g-code and controls the physical movement of the router. I went with Mach3, which is pretty much the default for homemade cnc users.
Being a home made machine means its not particularly speedy.From start to finish, the milling took about 1.5 hrs.

Apart from running the router into one of the holding screws! I was pretty happy with the results.
You can see it here still on the bed of the cnc:




After cutting the pieces from their holding tabs, they were glued togther and given a quick sand.
This how they looked:



And finally, how the pieces looked put togther:







My kids are mad on lego Harry Potter and lego Star Wars, so I told them I would make them figures to paint as they wanted. This was really just to get my feet wet and I will be scaling the next figure up. Then I'll look at working on some accesories (dependent on which figures they decide they want!)

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crackerjazz

Awesome job, Woodlake!

Leon Kowalski

that looks great! awesome job on the CNC router too!

closet geek

That’s great. Combine that with a nut cracker and you could sell a million of them

Lazlow

Woodlake

Thanks for the kind comments
I remember that someone was selling a number of CNC machines in the JY a while ago. Are these up and running yet?
I think it would be great to have a CNC area on the RFP...

jedimaster

That looks sweet. I think I got a job for ya mate.

Woodlake

Cheers Simon,
Let me know what you have in mind.

HAL9000

Imagine... The power to create your own Lego figures!!!

Too cool.

Woodlake

My kids are pretty excited to have this power!

Yodajammies

haha fantastic work!

That Rhino model ain't too shabby either!

Junk Pilot

Remember....with great power comes great responsibility and absolute power corrupts absolutely.

But then again "Supreme executive power drives from a mandate from the masses, not from some.."....never mind. You get it.

Rebo

Great work!!.
+1 for the CNC zone.

I'm really interested in your cnc build, do you have a build blog or info on parts, screws, steppers used and so on.

I cut my cnc teeth putting together a Zen Toolworks CNC 7"x7" which is really only good for engraving metal, circuit boards and milling of small plastic parts, I don't really use it much at all.

I'd like to move up in the world and build something along the line of yours though (angle and bearings) so I might sell the Zen to fund a new build.

Woodlake

Thanks YJ!


Thanks Rebo,
I can't take any credit for the design. It was built from the book "Build your own CNC machine".
A lot of folks build the book machine and then get it to make a better one!
It's a bit on the slow side, but seems to work very well. Quite an ingenious design using mdf, angle and skateboard bearings!.
The website has a helpful forum if you get stuck. Unfortunately for me the book is in imperial measurements, so took a little adjustment to suit metric and our stock mdf thickness. I did also opt for a different stepper motor/Break out board configuration to what is shown in the book, simply because it was easier to source in Aus. This is the kit I used for the motion electronics. I could have gone with cheaper motors/electronic, but now that I have them, they could be transplanted into an upgraded machine if I choose to go this path eventually.

Ronan87

Very nice but seems very expensive for a couple motors and a controller...

Woodlake

I could have bought a cheaper controller/motors, but when you consider that the (highly regarded) Gecko G540 is about $300 alone, and with the addition of 3x387 stepper motors & a 48v power supply, I thought the price was pretty good?