CNC Machine Basics: 7 Expert Tips for New Operators

Computerized numerical control (CNC) machines are used across various industries, ranging from aerospace to medical.

Operating a commercial CNC machine requires specialized training and distinct traits, such as a keen eye for detail, tech-savviness, creativity and problem-solving skills.

Because CNC machines use highly complex technology, they’re often accompanied by a steep learning curve. That's why the CNC Machining Technology program at Universal Technical Institute provides students with in-depth, hands-on training from experienced instructors. CNC machining students can graduate with a foundation of knowledge and skills that prepare them to pursue a career in the industry.1

If you're thinking about pursuing a career path in CNC machining but aren't quite sure yet, stick around! In this article, we’ll discuss how to use a CNC machine, what it is, what it’s used for and why CNC machining could be an exciting career.

What Is a CNC Machine?

CNC machines are controlled by computer software that uses a mathematical coordinate system to direct various tools across multiple axes on the machine. It is a highly efficient process when compared to manual machining.

The tools cut, mill, drill, tap and shape the material to create a specific product. Many people confuse CNC machines with 3D printers. However, CNC machines produce by subtracting material from a larger workpiece, while 3D printers produce by adding material. CNC machines can be used with various materials, including wood, plastic, foam, composites and metals such as aluminum, steel and more.    

What is a CNC machine used for?

Large manufacturers across various industries rely on CNC machines because they can mass produce products ranging from electronic parts to jewelry to car components quickly and accurately. There are multiple types of CNC machines, including industrial and hobby machines.

The one a machinist uses depends on the material they’re working with and what they’re creating. The most common industrial CNC machines include:

• Router machine: Routers are known for their quick and clean work. They have three to six axes and are ideal for creating intricate products.
• Milling machine: This is one of the largest CNC machines on the market. It has three to six axes and subtracts material by milling, tapping, drilling and turning.
• Lathe machine: Small and compact, lathe machines shape products by cutting away material as it rotates.
• Plasma cutter: Plasma cutter machines rely on a plasma torch to melt away the material being cut. They’re best for 2D solid materials, like steel.
• Electric discharge: An operator places a workpiece between two electrodes while the machine calculates the level of electric discharge needed to subtract material.
• Laser cutter: As indicated by the name, this machine relies on lasers to cut and shape the material. The lasers are adjusted according to the material density.

Most hobbyists invest in small CNC router machines. Hobby machines are typically limited to softer materials like wood and plastic. There are more advanced machines on the market that cut hard metals, but learning to use them safely and accurately takes more time and professional supervision.

Who Uses a CNC Machine?

As previously mentioned, multiple industries rely on CNC machinists to manufacture goods that are crucial to their line of work. Some industries that commonly use CNC machines include:

• Aerospace.
• Transportation.
• Defense.
• Firearms.
• Commercial.
• Electronics.
• Medical.
• Optical.
• Oil and gas.
• Marine.

Machinists’ responsibilities include stocking materials, performing maintenance and evaluating the final products to ensure they're up to standard.

They also read blueprints to create a code the CNC machine can understand, known as G-code. G-code is what directs the machine's tools to create a specific product.

CNC machines are commonly used by trained professionals, but many people with a fabrication hobby take an interest in them too.

7 Tips on How to Use a CNC Machine

Because CNC machines are highly complex technologies, they take a lot of time and instruction to use safely and properly. If you’re starting as a hobbyist, here are a few tips on how to run a CNC machine.

1. Understand what you are using the machine for

Before beginning the machining process, it’s important to evaluate what you’re creating and what purpose it’ll serve. Once you know this, you can choose a material and identify which particular CNC machine is the best fit for the job. This step will also help you develop a design plan using your preferred software.

2. Learn how the software works

Learning to navigate software can be tricky and takes time. Most CNC software consists of three parts: CAD, CAM and G-code, while others consist of CAD and CAM software but call for a separate G-code sender. So, what does all this mean?

CAD stands for “computer-aided design.” CAM stands for “computer-aided manufacturing,” and G-code is a language that communicates your project ideas and specifications to a CNC machine.

We’ll cover each of these concepts even further below. But first, you'll want to familiarize yourself with your software’s capabilities.

3. Draw out your idea

CAD software can help you get your ideas on screen. CAD software contains a graphical user interface that allows users to create and manipulate 2D and 3D objects.

To shape the object, users fine-tune the geometric parameters. This is also the step where users will be able to determine whether their design ideas are realistic or not. With that said, CAD allows manufacturers to create precise and durable products.

4. Prepare materials

Now that you know what you’ll be making, you should be able to determine which material to use. If you’re still having trouble, consider the following:

• Environment: What kind of environment will the finished product be used in? For example, if the product will be placed outdoors, it will need to be made from a durable material.
• Strength: Strength is inherent to the material, so ensure the one you choose is a good fit for your design and the finished product’s purpose.
• Dimensional tolerance: Tolerance refers to how precise the finished product needs to be to the planned measurements to meet safety standards. Some materials provide more accuracy than others.

Once you know the design specifications of your workpiece, prepare your machine through a warm-up routine, which will ensure it’s at the proper operating range and a stable temperature.

5. Calculate the toolpaths

This step is slightly more complex than the CAD process. It is where you tell the CAM software what tools to use, where to subtract material and how fast and deep to cut. Put simply, you set coordinates for each tool to follow during the machining process.

The CAM system also helps users generate the numerical code, known as G-code. As mentioned above, G-code translates the instructions you created using CAM to your CNC machine.

For this reason, your CAM process will likely have a setup step where you have to answer detailed questions about your specific CNC machine and its tools.

6. Insert materials and begin the program

For this step, you’ll need your workpiece and workholding. A workholding is an apparatus or device that keeps the workpiece steady during machining.

The kind you use should correlates with your material and toolpaths. Common CNC machine workholdings include:

• T-slots: A table with long T-shaped slots across it. Machinists lay a workpiece on the surface and secure it with T-slot nuts and fasteners.
• Clamps: Come in various forms depending on your needs. They often work in conjunction with T-slot tables.
• Glue: A good option for thin or oddly shaped workpieces.
• Vices: Holds the workpiece between two ends. They are best for straight-edged workpieces as they can be restrictive.
• Bolts: This method is very secure and ideal for forceful cuts. It places bolts in the corner of the workpiece, so it does require extra material to ensure the toolpaths are not restricted.
• Vacuum table: Creates a vacuum beneath the workpiece to hold it down. It is best for flat pieces and a good alternative to clamps, vices and bolts.

Once you’ve set up your materials, ensure you’re taking proper safety measures by dressing in the appropriate personal protection equipment.

Now all that’s left to do is begin the program!

7. Clean up and conduct proper maintenance

CNC maintenance is crucial to the lifespan of your machine, as well as the success of your projects. It prevents premature damage as it keeps the various tools operating safely and properly.

Part of this maintenance involves post-project cleanup. It’s one of the most important steps to using a CNC machine, so make sure to clean your machine after completing your project.    

Different CNC machines have unique maintenance requirements, so be sure to follow the guidelines specified for your machine.

FAQs

1. Is a CNC machinist a good career?

CNC machinists have the chance to make a real impact. The skills they build during their training are in demand across essential industries, including the medical, aerospace and transportation fields.

2. Do CNC machinists make good money?

According to the Bureau of Labor Statistics (BLS), the median annual salary for CNC operators in the United States was $49,970 in May 2024.34 This means half of CNC machinists earned more and half earned less. Keep in mind that salary depends on several factors, including experience, employer, demand and cost of living in the area.

3. How long does it take to become a CNC machinist?

At UTI Mooresville, students can complete their CNC machining training in just 36 weeks. Upon graduating, they are prepared to pursue entry-level CNC work in several industries.

4. Is becoming a CNC machinist hard?

CNC machining isn't for everyone. In addition to specialized training, CNC machinists require specific characteristics such as attention to detail, dedication, adaptability, creativity, critical thinking and organization.

5. How to operate a CNC machine: What are the basics?

Initially, the design is created in a CAD program and then converted into a CNC program using CAM software. Finally, this program is loaded into the CNC machine, and after setting up the required materials and tools, the machine can be started to produce the component.

Train To Use a CNC Machine at UTI!

Universal Technical Institute in Mooresville, North Carolina, offers a CNC Machining Technology program that can be completed in just 36 weeks. In the following CNC machining courses, students can understand how to use a CNC machine and gain the practical skills needed to pursue careers after graduation:

• Basic Machine Shop Skills.
• Mathematics, Materials and Maintenance.
• Interpreting Blueprints/Job Layout.
• Manual Machining Basics.
• Manual Machining on the Lathe.
• Manual Machining on the Mill.
• CNC Basics.
• CNC Turning I & II.
• CNC Milling I & II.
• CAD and CAM.

The curriculum taught in these courses was developed in conjunction with Roush Yates, a leading brand in the performance industry. Additionally, brands like Mastercam, Mitee-bite and Mitsubishi Materials team up with UTI to provide students practice using the tools and technology seen in the field.

Want to learn more? Click here to request more info or phone an Admissions Representative at 1-800-834-7308. If you’re interested in turning your passion into a career, fill out a CNC Machining Technology program application!