CNC Mill Rebuild

Update from 10/23:

TLDR: 

Problem: writing my name takes too much time. 

Solution: spend 40+ hours making CNC Mill driver to write my name for me (with ✨ GCODE ✨). Also, lets make it from scratch, litterally hardware components on a breadboard and base C with no libraries other than standard libs!

Date started: August 2021, Summer between Freshman and Sophomore year of college

There were some old Sherline CNC mills and CNC lathes at my high school, that were forgotten about and collecting dust. Some teachers from my school reached out to me to see if I was interested in taking the equipment! I of course said yes! Below is a link to the Sherline website to see their products.

Here is a video of the equipment I got.

Of all of the equipment that I got from my high school, there was a CNC mill in reasonable condition, so I focused my efforts on fixing the mill first.

I started by taking the mill completely apart, cleaning all of the parts, replacing any broken parts from the other mills, and then I put it all back together. Here are pictures of what it looked like before and after.

By the time that I got it cleaned up, it was time for me to move back to college for my sophomore year, so I packed up the mill, and moved it to my dorm room as any good engineering student would. Here is a picture of the mill in my dorm room.

My mill was operational if you turned the knobs manually, but I wanted to make the mill CNC. It had stepper motors on all of the axes, but they were not connected to anything. The mill sat in my room not getting any attention, as I had other course work to do.

Eventually, however, I had an embedded systems class, and our final project was to write a program and creates the circuitry  to solve a real world problem with an embedded system. I asked my professor if I could fix my mill and make it operational for my final project, and he said yes!

For the rest of that quarter in school, I spent most of my free time programming and creating the electronics for my mill. I bought some stepper motor drivers for each axis, cut up an old laptop charger from good will for the power cable, and threw some other random electronics into the project.

In the end, I got the mill to work! I wrote a program that can read g-code from fusion 360 cam software, and then turn that into movements for each stepper motor to cut out the part.

This was a massive project, so I am not going to go into detail of what I did and how I did it here, but I will link the lab report that I submitted for the class as it has a lot more of the technical details and the code for this design.

A note about the code for this project: I wrote all of the code for the mill from scratch :) You can see all of the code in the Lab Report.

Here is a video of the mill drawing out my name! This was the video that I submitted for the embedded systems class, so you can hear me talking about all of the operations of the mill.

A slight issue with this mill is that when I put a cutting bit into the mill, and turn on the cutting head motor, the electronics that control the movement of the axes "buggs out" and the motion becomes very choppy or the axes don't move at all. I think the issue is that the spinning cutting head creates a lot of electrical noise that the MSP board picks up. I may solve this in the future by enclosing the electronics in a metal box to reduce noise. For now, I just put a sharpie in the holder to show a proof of concept that the mill would work. I am looking forward to working on this in the future to make this a more functional tool!

Schematic and high level design overview