What is CNC Machining?: A Shop Floor Perspective

For a long time, I thought CNC was a fairly narrow subject—perhaps laser-etching a shape or a word into a piece of wood. It wasn’t until about five years ago that I finally put two and two together and realized CNC machining wasn’t just a single tool or trick, but an entire world of manufacturing that I had yet to delve into.

          Today, I’m training to be a CNC programmer at B&R Machining & Fabrication, Inc., learning first-hand by our Lead Programmer Tristan who’s been with the company for roughly a decade. I’m 24 years old, and while I still consider myself a student of the trade, I’ve learned enough to appreciate just how foundational CNC machining is to modern industry—and how misunderstood it often is from the outside.

So, what is CNC machining, really?

CNC, Defined

          CNC stands for Computer Numerical Control. At its core, CNC machining is the process of using computers to control machine tools—mills, lathes, and related equipment—with an extremely high degree of precision.

          Instead of manually turning handles or relying on operator intuition alone, CNC machines follow programmed instructions that dictate exactly how a cutting tool moves through material. Those instructions control things like position, depth of cut, feed rate, spindle speed, and sequence of operations. Once a program is proven, the machine can repeat that process again and again with remarkable consistency. This is what allows CNC machining to produce parts that are not only accurate, but reliably identical across short runs, long runs, and everything in between.

How CNC Machining Works in Practice

          While every shop has its own workflow, CNC machining generally follows a similar path:

First, a part is designed using CAD (computer-aided design) software. That design is then translated into a machine-readable code called "G-code" (example below), which tells the CNC machine exactly what to do. From there, material is selected and secured, tooling is installed, and the machine is set up for production by our Setup Tech.

          Once machining begins, the CNC equipment removes material in a controlled, deliberate way—cut by cut—until the finished part emerges. Afterward, parts are inspected and measured to verify that they meet dimensional, functional, and quality requirements.

          What sounds straightforward on paper becomes far more nuanced in reality. Tool selection, workholding, material behavior, and sequencing all matter, and decisions and actions as miniscule as locating the decimal in the right place can have a very large (or expensive) impact when its all said and done.

Why CNC Machining Matters

          CNC machining is everywhere because it solves problems that manual methods simply can’t solve at scale.

It offers:

• Precision, allowing for tight tolerances and complex geometries

• Repeatability, meaning parts don’t change from one run to the next

• Efficiency, once programs and setups are properly developed

• Flexibility, supporting prototypes, repair work, and full production

• Material range, from common steels and aluminum to plastics and specialty alloys

Considering say, transportation, industrial systems, or infrastructure-related components, CNC machining isn’t optional—it’s essential.

CNC in the Real World

One of the things I’ve learned quickly is that CNC machining isn’t about pressing a button and walking away. It’s a collaboration between programming, setup, machining, and inspection. It’s problem-solving as much as it is production.

At B&R Machining & Fabrication, CNC machining is the backbone of what we do. Every job—whether it’s a single prototype or sustained production—relies on the same fundamentals: thoughtful programming, proven processes, calibrated equipment, and consistent inspection.

CNC isn’t just a technology. It’s a discipline. And once you start to understand it, you realize just how much of the modern world quietly depends on it.

-researched and written by Tanner Stanley