I’ve been working on a Digital Fabrication Technique for building precise 3D-faceted forms. I ended up making an armature, which is close to a good solution, but still has too much play in the joints.
One of the other resident artists at Autodesk, suggested a solution where I make wooden squares to solidify the joints in the armature. I cut out a variety of squares, each with a slightly different width+height, to account for the kerf of the laser-cutter. I also laser-etched them with their measurements.You can see here where I cut out a groove in the bottom of the armature, 1/8″ deep. The square fits nicely in there. I found that 25/1000″ seems to be the right amount of compensation.
I also added squares for the top joints.
Using the brad nailer, I adhered the bottom squares to the armature.
Then the top squares and then the bottom panel of the structure.I built up the structure quickly. The precision of the armature made it easy to align the wood-paneled faces.
This is what it looks like before I put the last panel on.
And done! No glue or anything. Easy assembly.
It looks just like the model!
After the “Digital Fabrication Fail” based on my self-defined Fabrication Challenge, I’ve gotten closer to a more precise solution. After an evening of frustration, while riding my bike home, I realized that an armature for the 3D sculptures would be the solution.
This is a bit tedious design-wise since I’d have to custom-design the armature for every 3D form. However, it would work — I remembered the Gift Horse Project and the armature that we built for this.
I designed a quick-and-dirty armature in Sketchup (I know, I know…) and exported the faces to Illustrator with an SVG exporter.I then laser-cut the armature pieces and put them together.
I made a few mistakes at first, but after a few tries got these three pieces to easily fit together.
However, even with accounting for the kerf, there is still a lot of play in the structure. You can’t see it in the images, but I can easily wiggle the pieces back and forth.
If I model the tolerances too tightly, then I can’t slide the inner portions of the armature together.
It is certainly an improvement, but I’m looking for something that has more precision and is still easy to assemble.
I’m working on some simple tests or my Faceted Forms Fabrication Challenge . I started with this model, which has 10 faces and is relatively simple.
Then, I laser-cut these pieces from a 1/8″ sheet of wood.
And, I also cut out these joints.
Then, using the brad nail gun and glue, I began with the base and built up the structure using the joints for support.The first level, with the rectangular base went well.However, when I started assembling the trapezoid sections, I quickly ran into problems. The nail gun pushed the joint blocks away from the wood, and it was difficult to align the joint pieces correctly. I had to redo sections over again. Although this photo doesn’t entirely capture the first-try-failure, you can see the nail holes everywhere and also the gap between the joints. I threw in the towel pretty quickly and went home to sleep on the project, and hopefully, will come up with a better solution.
Every cutting tool has a kerf — the amount of material that the tool itself removes in the cutting process. With a table saw, it tends to be large, like 1/8″. The laser-cutter has a small — but significant kerf.
I cut a 1/4″ notch and then used the calipers to determine that I have a 2/100″ kerf when cutting 3/8″ material at 8/100/500 (speed/power/frequency).
I then cut a 1/4″ groove and several notched cutouts, increasing the amount of material by incremental values. At 4/100″, (double the .02 measurement), the fit is perfect. 3/100″ is a little loose and 5/100″ won’t fit.
I’m glad I was a high-school mathlete.
I just got trained on how to use the water jet tool at Autodesk and made this piece of bling as my sample project. The design came from my Grantbot project.
Anyone have some gold spray paint?