Computer-Controlled Machining

Group Assignment

1. I learned how to safely operate the CNC machine.

Unfortunately, I was sick at the beginning of the week so I could not attend the group training session with the rest of the architecture students. However, they sent me pictures of tests cuts of particle board, which they measured using calipers (Fig. 1A). While the thickness of the board was supposed to measure 0.5", in reality, the boards varied slightly and were often around 0.45".

I received the rest of the safety training individually from Technical Instructor Chris Dewart.

Individual Assignment

2. I designed a side table

Being my first time making any sort of furniture, I wanted to make something useful that I could keep..

This was my design inspiration for my table. I wanted a work table to use when sitting on my sofa.

This was the initial 3D modeled piece. Here, the height of the table is 30" and the legs are 2.5". It has two main support frames with joints that enable the table assembly without glueing and nails.

I sent my CAD file to Jen, who suggested to make the top platform sturdier by adding additional support frames and adjusting the lengths of the legs. I updated the CAD design accordingly (Fig. 2D).

This is the updated design. I added one more support in the bottom for added stability as well as another one below the top panel. In addition, a panel is added to place feet on top of the bottom framing to rest feet. The desk height is shortened to 28" and the edges of the table surface is filleted as an added detail and safety.

Chris opened my template in Rhino and and showed me how to modify it in order to set the toolpath This included adding points to the inner corners that would be cut in order for the program to recognize where to start and stop the tool.

When the file was ready to be uploaded to the CNC machine, we set it up for cutting. The "C.R. ONSRUD" is a massive machine that includes a fast-moving cutting unit programmed to cut a material affixed to the platform underneath. In preparation for this process, Chris and I carried a large piece of particle board (8' by 4') from the nearby shed and placed it flat on the platform. To secure it down, Chris drilled a few screws into the corners of the board. We uploaded the cutting template to the machine via USB and then started the program. Watching the machine start, I was mesmerized by the automatic process of the cutting unit changing tools.

The machine began cutting the particle board, taking around 20 minutes to finish. Once complete, we realized the z-axis depth was not set to the full thickness of the board, so we had to run the program again in order to cut through the board. When the cut was finally complete, we vacuumed off the sawdust that was remaining within the grooves on the board and then removed the parts. We then removed the excess material from the platform of the CNC machine to recycle or reuse for future projects.

All the parts have been milled approx. after ~20 min later I scored the edges of the cut parts with a utility knife before taking the individual parts and vacuumed the machine to clean all the dust produced from the job.

After sanding all the rough edges of the furniture parts, I began assembling by placing one of the legs onto a flat surface of the work table and hammering down the joints of frames onto it.

Overall, I am really happy how it has turned out. The table is much sturdier than I anticipated. I am looking forward to using it sitting on my couch. For next steps. I would like to further smoothen the surfaces and edges of my table, and potentially coat it with resin material to avoid getting splinters.