What Does a CNC Operator Do?

09/24/2019 | Rob Schmitt


The metalworking industry needs more qualified CNC operators. This rewarding career requires a broad skill set —math, mechanical design, interpreting technical drawings and programs, eye for detail — to properly transform a metal casting into a valuable working machined part. It’s a unique fusion of digital and physical, brains and hands-on work. Before taking a look at a typical fast-paced day, let’s explore what a CNC machine actually is.

A computer numerical controlled (CNC) machine uses a program to control the operation of machine tools such as lathes and mills. It takes a raw material (metal, plastic, etc.) and cuts, grinds, drills, turns, mills, and/or shapes it into parts that meet exact specifications. “Exact” is a key word for CNC machinists. Fractions of a millimeter make a difference, and there’s very little room for error.

Why does a machinist need rhythm? 

One key to a fulfilling day as a machinist is to have a routine that allows you to get into a rhythm. You’ll be constantly refocusing between different tasks in your work area: changing a part, inspecting a part, observing tools, etc. Establishing a smooth rhythm not only maximizes your efficiency but also makes the day appear to fly by as you always know what you should be accomplishing at a given time.

Although no two work days are exactly the same, here’s a look at some typical CNC production operator tasks and situations.

Let’s get to work!

After punching in and putting on safety gear, you report to your assigned work center. Your first 15 minutes is gathering the supplies you need for the day and talking with the previous shift operator, who shares any machine or part quality issues you need to know. This teamwork minimizes surprises and allows an operator to plan tool changes and audits for maximum efficiency. Each fixture is designed differently, so you check the provided loading instructions for this part to ensure your technique will be right. After all, these precision machines are advanced technology requiring exact techniques that are critical to successful performance.

You unload your first finished part to the deburring bench, where it will be blown free of chips and coolant. You blow off the fixture removing any chips that could cause misloads or damaged parts. You load a new, raw part onto the fixture. You double check that the part is properly loaded. The rhythm has already started.

Quality control starts immediately.

You get back to the part on the deburring bench. Each part has specific instructions for deburring, which is removing small metal pieces still attached to the part after machining. This first part needs to undergo an in-process audit, a check of all-important part dimensions using a variety of measuring tools: a caliper, bore gages, pin gages, thread gages, depth gages, and both ID and OD micrometers.

An audit schedule could be every 2 or 4 hours, every hour, or even every part, depending on how critical the feature is to ensuring part quality. After your audit, the part is inspected by quality assurance on a Coordinate Measuring Machine (CMM) to verify all dimensions and positions are in tolerance, not just the critical ones covered in your audit.

Lunch break!

During lunch, you enjoy a chance to catch your breath. You may reflect about how your production is going and expectations for the afternoon. It feels good to take a design and create useful, physical parts from it. Now’s also a good time to share with coworkers any ideas you have about work conditions, increasing productivity, or improving a particular cutting tool.

The rhythm continues.

As a CNC operator, you’re always focused on keeping the machine running at capacity and meeting target rates. Throughout the day, you’re also monitoring the tooling used on each part to ensure that each one is performing properly. A dull tool causes excessive burrs or out-of-tolerance dimensions. You watch for part quality as you deburr them, listen for the machine sounding different than normal, and hearing the machine’s alarm for tool life being met. 

You’ve reached the end of your shift! You overlap for 15 minutes and keep the machine running for the next operator. You share how the machine and parts ran for the shift, record production, and wash up before the bell rings.

From one day to the next, (or even one hour to the next), you could be using lifting equipment to move parts and equipment, cleaning and packaging completed parts, performing changeovers, collaborating with another team member, or meeting with customers.

Now that you know what a CNC operator does, how does someone become a machinist? Many machine shops like Stecker Machine train CNC operators. Being successful in training takes a drive to learn and diligence to run machine. Skill can be furthered at local technical school or community college, that offer classes to develop skills like math, 3D design, and blueprint reading and specialized CNC machinist training. CNC machinists usually experience plenty of job opportunities and healthy wages.

Many CNC machinists enjoy their various job responsibilities: taking on mechanical challenges, setting up equipment, using hand tools and precision measuring instruments, controlling quality, and even supervising or managing other CNC operators.

At Stecker Machine Company, we primarily machine aluminum and iron castings. We have state-of-the-art CNC equipment, so we can meet our customers’ stringent quality requirements.  Our plant offers a safe and efficient production environment. Want to join our team as a CNC operator? See our current job openings.


Rob Schmitt

About the Author

Rob leads Stecker Machine's Bay 1 first-shift team, supervising 28 Manufacturing Operators. In addition to assisting scheduling by aligning his team to jobs and machines, he's accountable for the On-Time Delivery program and process improvement projects. Rob began his SMC career as an entry-level Machinist and worked his way up to Setup Operator, Leadman, and current Supervisor. His biggest accomplishment? Working, getting his degree, and starting a family ... all at the same time (life was pretty hectic).