Week of May 25: First Parts, Fresh Coolant, and Real Machining Lessons

We are wrapping up the second week of the semester, and there has already been a lot of excitement in the CNC machining program.

This week was week two of CNC lathe, and the students have been working hard. We started with safety, moved into basic G-code programming, and then they reached one of those milestone moments that every machining instructor loves to see: they ran their first part.

The part itself was simple, but the lesson behind it was big. In machining, every complex program starts with understanding the basic format. Once students begin to see how G-code is structured, they start to realize that programming is not just about typing numbers into a machine. It is about understanding the process, planning the toolpath, and learning how to communicate with the machine.

This week, the students wrote their own G-code programs and used a single tool to complete both roughing and finishing cycles. When they saw the machine follow the code they had written and produce an actual part, the excitement in the room was easy to see. Their eyes lit up because the process started to make sense. They were no longer just talking about CNC machining. They were doing it.

Next, we will begin introducing threading and multiple-tool operations. That is where the process starts expanding, and students begin to see how each new skill builds on the one before it.

Thursday also gave us a great opportunity to teach another important side of machining: machine maintenance. Some of the coolant in our machines was not testing where it needed to be, so we cleaned the coolant tanks, changed the coolant, and refilled the machines. This gave the students a chance to learn how to use a refractometer and understand why coolant concentration matters.

I like to run our machines around 7 percent coolant concentration. In my experience, 7 to 8 percent gives a good balance. It helps with tool life, improves surface finish, and helps protect the machine from rust. At the same time, it is not so heavy that it gums up the inside of the machine or leaves every corner green and difficult to clean.

Anyone who has worked with coolant in CNC machines knows it is a balancing act. You need enough concentration to protect the machine and support the cutting process, but too much can create its own problems. This was a great real-world lesson for the students. They were not just learning how to run a machine. They were learning how to take care of one.

That is an important part of becoming a machinist. Running parts is exciting, but maintaining equipment, checking coolant, cleaning tanks, and understanding preventive maintenance are all part of the trade. A good machinist does not just make chips. A good machinist understands the machine, respects the process, and takes pride in keeping the equipment ready to perform.

Two weeks in, this group is doing great. They are learning, asking questions, building confidence, and starting to see what they are capable of. I am excited to see what they accomplish this semester.