Introduction

In this week’s iteration of “What Will Mina Make”, we have a fun one: using a CNC (computer numerical control) machine, we needed to cut out a shape in wood. This shape could be a extruded svg, a piece with multiple depths, or a topography. I chose to start with a topography, but, as you will read, that went poorly, and for the sake of time, I had to switch to the intermediate assignment.

First Step: Making the V-Carve File

As I started out with the topography, I had to prepare the svg file given to me as a gcode so that the software for the CNC machine could use it. For this whole assignment, I used the Shapeoko Pro XXL CNC machine. I pulled up the Mount Everest file given on the CNC computer and imported it into a VCarve file. I had also selected a piece of wood and taken measurements of it so that I could specify the workspace for the piece. I put the specs into the file, then started to follow the directions given on the assignment file. This consisted of, among other steps, defining the size of the wood block, the rough cut passes and the smoothing cut passes, and the types of bits used. Additionally, I had to specify the cut depth and the file type. I eventually exported the file as a gcode and was ready to set up the machine to make my cut.

Second Step: Preparing to Cut

I first, though, had to set up my piece of wood to be ready to cut. I first vacuumed and kimwiped the workspace for the wood to be placed on. Then, I put double sided tape on the bottom part of the wood block and stuck it to the workspace. Then, I used the green clips to secure all sides of the piece. Once this was done, I could calibrate the machine.

Third Step: Calibrating the Machine

The next step was setting up the machine. I pulled up the CarbideCut program on the computer and initialized the CNC, allowing it to zero and find its home point. Following this, I put in the probing bit so I could calibrate the CNC to the bottom left edge of my wood piece on the workspace. I put the probing plate on the corner and the magnet on the edge of the bit holder. I then ran the probe, making sure to hold the plate so that the calibration would be as accurate as possible. After this had finished, I put up the probing plate and switched the bit back to the first one needed, the 1/4″ end mill bit. I was ready to start cutting.

Fourth Step: Fail (Number 1)

This is where I failed in multiple departments. The first failure is that the CNC booking would run out before my cut would be done. This would mean I would have to rerun the machine and I didn’t have another booking time that would allow for the full cut. Additionally, when I turned on the machine to go to start the cut, the spindle would not spin, which was bizarre. After consulting a lab assistant, they could not figure it out either. This was honestly disheartening because I had spent good time with the file and setting up stuff. To remedy this, I could’ve started this project earlier, but with my schedule I was unable to do so. So I think that this was just one of those ‘these things happen’ moments. But, I will say that I would like to go back and try to make something like this again. But I had to move on, so I stepped down a level of difficulty for the assignment.

Fifth Step: Prepare the New File

Sad, but ready to try again, I started preparing a new file to cut. I went onto the Noun Project and found a svg of MF DOOM. I uploaded this svg to CarbideCreate, and used the program to offset the contour cut of the outside, and used pocket cuts for the details of the mask, such that I had different depths of cuts. I also got a new piece of wood, measuring it so that I could input that into the file. I then exported the file to CarbideCut, but someone needed the machine, so I left and would finish another day.

Sixth Step: Cutting the Piece

Here is where I will note that I started this project with plenty of time (almost a week), but throughout all my setbacks, it extended to Monday night.

On Monday, I set back up my piece and probed, initialized, and started the cut of the piece. This is where the first error was, as the machine hadn’t probed correctly (?) and so the depth was off. I’m really not sure why this happened, and I had Amelia check all my settings and my file and she couldn’t figure it out either. At the end of the day, it took one pass to get to the proper depth to start cutting, so at the bottom of everything it was a cut above. It finished with no further hiccups and I pulled it off.

Seventh Step: Finishing the Piece

Once the piece was cut out, I was ready to finish the piece. When I pulled the piece off, I knew that I had to somehow get the piece out because there was still a god bit of wood to cut through at the base. I ended up using a box cutter to get through the bottom layer. While I was doing this, the wood showed its grain and pieces naturally ripped and chunks fell out due to the quality of the wood. This was annoying, but there was really nothing I could do about it now. I used a rasp, a file, a chisel, and sandpaper to smooth out the edges and get the inside of the pocket cuts as smooth and possible. The pockets hadn’t cut out smoothly, and in retrospect, I may have used the wrong bit, but, in my defense, I had pulled the bit out of a container which claimed to be the #102 bit we needed to use.

An hour later, I took the pieces outside and spray painted them black, finishing the project. I placed them on the 210 table, not very happy with the work, but glad that it was done.

          

Reflection

This assignment was frustrating just because of my big setbacks, but it was cool to use a CNC machine. I felt like some of the things that occurred during this assignment were avoidable, but some others weren’t. I could’ve double-checked the bit, but the timing of it all was tough because the pieces take awhile to cut and the checking-out system was hard to comply with as it was constantly full. I also felt that I followed all the instructions for both of the pieces, and yet something went wrong. I am frustrated, but I did my very best to meet all expectations for the assignment, and I feel that I finished it well, so there is that to be proud of. I did enjoy this assignment on the whole, just wish that it went differently.

Cost Estimate

•  10 hours of work for $20/hour: $200.00
• Around half a board-foot of lumber: $2.50
• Sandpaper, 2 sheets: $1.50
• Double-sided tape: $0.10
• Spray-Paint: $1.00

Total Cost: $205.10