3:1 Lego minifigure cut on CNC

Woodlake

Well-Known Member
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 :cool.

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! :cryI 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!:))
 

closet geek

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

Lazlow :darnkids
 
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Woodlake

Well-Known Member
Thanks for the kind comments :cool
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...:love
 

Junk Pilot

Sr Member
My kids are pretty excited to have this power! :lol
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.

:lol
 

Rebo

Well-Known Member
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.
 
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Woodlake

Well-Known Member
haha fantastic work!

That Rhino model ain't too shabby either! :thumbsup
Thanks YJ!

Junk Pilot said:
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.
:lol
Rebo said:
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.
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

Sr Member
Thanks YJ!


:lol

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

Woodlake

Well-Known Member
Very nice but seems very expensive for a couple motors and a controller...
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?
 
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