8. Computer controlled machining¶
Group assignment do your lab’s safety training test runout, alignment, fixturing, speeds, feeds, materials, and toolpaths for your machine
Individual assignment Make (design+mill+assemble) something big (~meter-scale) Extra credit: include curved surfaces
Safety Training¶
To work on a larger project using CNC, I had to learn more things and go through a safety procedure. Some things that I learned about was spindle speed, feed rate, and flutes, which are all used to calculate speeds manually given the components that I use. I also learned about different endmills such as a flat or ball endmills which result in different cuts.
Work¶
For this week, I used CNC once again but designed and created something large.
I had previously used Fusion 360 and CNC for other weeks, so I felt quite confident using the designs until I came across new concepts such as joints (which I did not work with much) and curves.
Initially, I thought of simpler ideas such as a chair or a table, but I realized that I wanted to design a harp since I play the harp myself.
I first started the designing process on Fusion 360, but I did not make much progress because I did not know how to account for the angles and the complex design of the harp. Therefore, my instructor helped me with the designing process using Illustrator. I drew the harp and then created traces on illustrator. From here, I moved the paths by downloading as a dxf file and then worked on it on Fusion 360.
I used extrude functions and circular patterns to create holes for the harp strings, but most of the designing was done through illustrator.
Here is the link to the Fusion 360 file!
- Link
- There is only a sketch, so the link will say there is no geometry. Please open the file using the link on Fusion 360! There was no extrusion because the sketch was moved to Aspire and the the sketch was used to simply cut the wood using CNC. The extrusion process was unnecessary because the width of the wood decides the width of the product.
After creating the design files, I worked on the files using Aspire, which I could not access on my Mac. Therefore, I borrowed the software which was already downloaded on the computer of the worker at Space 00, which is where I went to access the machine for larger CNC processes.
In Aspire, I made necessary changes and added multiple dogbones to allow connections in joint areas. Also, I realized that I wanted to make a thicker harp, so I duplicated all parts and created slots and dogbones for all the joints. I planned to glue duplicate parts together for the thickness.
The machine I used for large CNC was called Blue Elephant 4 axis CNC, and I observed the engineers at Space 00 prepare the machine. A vacuum was used to ensure that the plywood was completely stuck onto the bed without movement, and tabs were sometimes used to stabilize small pieces.
After the machine cut according to the toolpath, I tried to assemble the device, but I was unable to do so because the slots were too small for the dogbone I had designed. Therefore, I sanded the slots and the dogbones to allow a fitted design.
Here is the final product!
