I have not had much time recently to experiment with the new equipment that is coming into the workshop. However, I did manage to run a couple of quick samples through the new milling machine.
The software that runs the miller works with .stl files and these are fairly standard in the 3d modelling and rapid prototyping field. So as well as getting the hang of the machines I have been trying to find the time to learn to use some 3D modelling software. I am using Rhino for the primary work but I am also looking at some of the open source and freeware alternatives that are out there, namely Blender, Sculptris and SketchUp.
Ideally I would like to use SketchUp as it seems the simplest to pick up. However the free version is limited in the formats that you can save (or export) the files in. I do have a pro licence for SketchUp, but I am not sure how far down that road I am going to go. It may turn out to be better to persist with the more advanced software as once I know what I am doing with it it should be quicker to use.
Sculptris is somewhat different to the other software I am using in that it is an organic sculpting tool (something of a younger cousin of Z-Brush, which I can’t justify buying at the moment). Sculptris will come into it’s own with the figure sculpting side of things and I think that combining it with the 5 Axis milling machine and the 3D printers it should prove to be a very interesting tool to develop designs on.
As for my first attempts at running a file on the milling machine, the installation came with several sample models, which the engineer ran through with me. Once I had played around with those I wanted to try something for myself. As I am not far enough down the road of learning to create 3D files just yet I hunted round and found a 3D model of a treasure chest online that seemed like a good test piece!
The file was in an .obj format so first I took it into Rhino and converted it to an.stl file.
Then I transferred it to the software that drives the milling machine and set up the job. While I am still learning to use the machine I have decided to stick to cutting styrofoam. It cuts easily and will not damage the machine if i inadvertently crash the cutter into the material.
The first attempt confirmed my decision to use styrofoam, as the depth of the cut meant that the collet that holds the cutter did crash into the foam. Fortunately as I was using the foam, gave way under the tool and caused no harm.
As you can see the result is not exactly fantastic, but as a first attempt I learned a lot and found it very useful. I used a 6mm end mill on this one, which proved to be to large for a lot of the detail.
You can see the rough lip at either end of the chest where the collet crashed into the foam. Also, the shallow angle of the slopping lid of the chest led to some fairly heavy stepping.
For the second attempt I reduced the size of the end mill, down to a 3mm cutter and reduced the overlap of the tool passing over the surface. This meant that the job took a good bit longer to run, but produced a much finer finish. I also spent more time working out the cut path so that it didn’t crash into the material this time.
Clearly still not perfect, but a vast improvement on the first attempt!
I still have a long way to go with this, and I definitely need to spend more time learning to use the actual design software. Still the initial playing around is fairly positive and I am getting more and more enthusiastic about my new toys!
A couple of days after posting this article the Fabbaloo 3D Prinitng blog posted this article about creating printable models using SketchUp. I haven’t had a chance to fully digest it, but this will be a big help when I get far enough on to actually start designing for 3D print.