Intro: Love Letters to a Machine
I frequently think about the projects that I make as love letters. For me, the process of taking the time and attention to really try to better understand someone or something and to pack it up in the form of an object, a process... Well that packet, that unit of presentation becomes something akin to the envelope of a love letter. In this project the letters are written in triangles and aluminum.
Questions I explored in this project:
- How does a 3D scanner see us?
- How does the Haas see me?
- How can I get it to understand my physicality?
- What can I do to enable it to trace my outlines with only a 3-axis toolpath?
A special thanks goes out to Julie Kumar for her encouragement, mentoring, labor, and enthusiasm. I came to Pier 9 with no previous CAM or CNC experience and without the CNC Learning Path and lots of one-on-one training time with Julie this project would not have been possible.
Step 1: Scanning
There are many ways to accomplish 3D scanning. Because I was focused on rapid iteration I used a method that was simple and quick - the Occipital Structure scanner along with a software called Skanect.
Here's the process:
Plug the scanner into your computer with the "hacker" cable. This scanner can also be used via an iPad but I find it to be a bit more responsive when plugged directly into a laptop.
Open the Skanect software. It's important to do this after you plug the scanner in, otherwise it won't recognize it.
Set the scene to "Body".
Set the bounding box size depending on whether you are scanning body part or a whole body.
You will see a preview. Position your camera and press the record button. Move slowly over the surface you are covering. Be sure to thoroughly cover any nooks and crannies. When you are done click stop.
Next move on to the Process tab. First use the "Remove Parts" function. Then, if necessary, rotate it in the "Move & Crop" tab. Then, in "Fill Holes" select "Watertight" and "Medium", then "Run".
Finally, under the "Share" tab select "Export Model". Set the format to STL and scale to inches, then Export your model!
Step 2: Modeling
To prepare and convert my meshes I used Rhino. Here's the routine:
File -> New -> Small Objects - Inches
File -> Import and then select your STL
I know my stock is 8" x 2" x 1".
Elevating my stock with 1.5" parallels means that 0.24" will be gripped by the vice. I will also offset my model 0.05" below the stock top which leaves 0.71" for my model. I'll use 0.7" of this for my body part and 0.01 for a base rectangle. This is a helpful reference when defining the stock box later since the body parts tend to be weird irregular shapes.
Create a box measuring 8" x 2" x 0.7" and position is over the surface area of the body intended to be milled. Make a copy of the box and offset it a bit along a single axis to maintain the same positioning. Change it's height to 0.01". Use the MeshBooleanIntersect command to combine the 0.7" box with your scan. Once it has been cropped, move the 0.01" box to kiss the bottom of the cropped surface.
Select the mesh and use the MeshToNURBS command to convert it to a polysurface. Select the resulting polysurface as well as the base box. Then go to File -> Export Selected and export to a STEP.
Step 3: CAM-ing
Open Autodesk Inventor.
Go to File -> Open -> Import CAD files and import the STEP.
Select the CAM tab. Create a setup. Define stock and work coordinate system. Determine toolpaths.
The toolpaths differed depending on the type of surface I was working with. Some required more detailed roughing and finishing while others could simply be done with an Adaptive followed by a Parallel path.
Step 4: Machining
At first I would make one, machine it, think about it, and then go back to the next. But after a few days I moved on to batch processing, machining between 5 and 9 a day. Machine time is a precious resource and once you're set up it's a lot easier to do many at once.
My daily preparation included:
- Preparing scan files
- Preparing & checking CAM*
- Printing setup sheets
- Cutting lots of stock*
*Julie Kumar gave me extensive of help and support with these tasks. Working together we were able to create much more of an assembly line approach than I could have achieved on my own!
Once these things were done I'd setup the machine and get my groove on. I found that doing preparations in the morning and then machining after lunch until 7 or 8PM worked really well for me. Later evenings were a perfect time to socialize and scan.
Generally these pieces all took between 15 and 45 minutes each to machine.
Step 5: Iterating
The goal of this project was to push quickly and fluidly through the process of creating these body panels / body parts / body surfaces. In the same way you can glimpse parts of the body through looking, I wanted to establish a roughly similar method of glimpsing the body through machining. At first it felt like I was struggling and straining to push my body through the machine. As time went on it felt like I was letting the machine drink in glances of myself and others, a kind of curious exposé of "this is what people look like".
Ultimately I produced approximately 40 panels in 8 days. Many have errors, issues, or artifacts that weren't intended but I see them as an archive of correspondence - a getting-to-know you process milled out of aluminum. The intensity of of the experience felt like a surreal mashup of Production (with a capital "P") and rapid-onset Intimacy (once again, capital "I"). I was flying out soon and after chatting for a couple months the Haas and I had a fling just before I left.
I am interested to step away and view these pieces again in a few months once I've cleared my head. I know there are smaller selections, themes, and groupings to be pulled from the whole. But in the meantime they remain a collection of love letters to a machine.