CNC Machining: An Intro Guide for DIYers and Hobbyists
Some people like to work on computers. Others like to make stuff with their hands. If you're a DIY type who enjoys both pursuits, you're probably intrigued by CNC machining. Ideal for precise and efficient work, CNC machining is a fascinating combination of the digital and industrial worlds. If you're considering getting into CNC in your workshop, we hope this intro guide is a good place to start.
Definition of CNC Machining
CNC (computer numerical control) machining is a manufacturing process in which software controls machine tools such as lathes and mills. By automating these processes, CNC creates complex parts to tight tolerances at high volumes.
CNC machines first emerged in the 1970s. These machines built on the success of NC (numerical control), which used punched tape to store machine instructions. Since then, CNC machining has become an integral part of modern manufacturing production.
The global CNC market was worth $56.4B in 2021, according to Grandview Research. Experts expect the market to expand by 10.2% from 2022 to 2030.
CNC capabilities are in hot demand in industries including:
- Medical device manufacturing
Types of CNC Machines
Some of the most common types of CNC machines include:
- Lathes – A motor rotates a workpiece around a central axis. A variety of different tools cut and shape the material.
- Mills – Rotary cutters remove material from a workpiece.
- Laser cutters – A powerful laser cuts intricate shapes in a variety of materials, including metal, plastic, and wood.
- Plasma cutters – A high-energy plasma arc cuts through thick metal and other conductive materials.
- Waterjet cutters – A high-pressure stream cuts through materials including metal, plastic and glass. These machines help create precise and intricate shapes, as well as cut materials that would be damaged by other cutting methods.
- 3D printers – Nozzles or extruders build 3D objects layer by layer from a variety of materials, including plastics and metals.
Inside the CNC Machining Process
- Like other machining processes, CNC always starts with a good print. In this case, you'd create your part drawing with computer-aided design (CAD) software.
- Then, you need to convert the CAD design into something called G-code – the language of CNC. You can do this with computer-aided manufacturing (CAM) software.
- Load the G-code program into the CNC machine to set the machine up with the right tools and materials. Now you're ready to cut and shape your material and make your part!
Open- and Closed-Loop Systems
The type of control system that guides the movements of the machine is a key distinction in CNC.
The basic type, open-loop control, lacks a means of verifying instructions. It relies on the G-code to provide instructions for the machine tools. If the machine tools do not follow the instructions correctly, open-loop control system can’t detect or correct the error.
The more sophisticated type of control is closed loop. In this system, sensors measure the movement of machine tools and compare it to G-code – adjusting as necessary to correct errors along the way.
It’s easy to see why closed loop control supports tight tolerances, but also comes with higher cost and complexity.
What You Can Do with CNC
With the right skills and equipment, CNC enables production for a huge range of projects.
Here are a few examples:
- Precision parts for your machines, including gears, bearings, mechanical components, etc.
- Prototypes – Have an idea for a product? Use CNC to test out your design.
- Replacement parts – Quickly repair or make new parts your equipment needs.
Coolest Things Hobbyists Do with CNC
You’re limited only by your imagination (and your skills, of course). When you get the hang of CNC as a machinist, you can make some amazing pieces to give or even sell as a side hustle. Here are a few ideas to get you started:
- Custom engravings – Create custom signs, plaques, and engravings as gifts.
- Artistic projects – Make sculptures and other decorative items.
- Home decor – How about a unique lamp shade, candleholder, or shelving unit?
- Toys – Check out this overview on making metal spinning tops.
Advantages of CNC Machining Processes
It's no surprise that CNC machining has become a go-to production process in many manufacturing environments. Here are a few of the reasons you might want to add CNC capabilities to your repertoire:
Precision and accuracy – Make parts and projects that are more exacting than what you could achieve with traditional machining methods.
Versatility – You name it; there’s probably a CNC machine that’s up to the job.
Efficiency – Produce parts and projects quickly and with minimal waste.
Safety – Avoid the risks of manual operation of powerful equipment.
- Personal satisfaction – Take pride in overcoming the learning curve to make your cool creations!
Drawbacks of Doing CNC Machining in Your Shop
All right, so what's the catch? Truth be told, CNC machining is not without significant challenges, including:
Cost – Probably the No. 1 drawback for a hobbyist. Depending on the size, capabilities and condition of the machine, CNC equipment can cost anywhere from a few hundred dollars to several thousand.
Limited size and capacity – If you want to create large, heavy parts, you may not have room in your workshop or budget for the right CNC equipment.
Maintenance – The advanced technology of CNC machining can make for difficult, time-consuming repairs.
- Complexity – CNC machining takes a deep understanding of both the machine and the G-code programming language.
Speaking of which …
How Hard Is It to Learn CNC Programming?
As you can imagine, you need some technical knowledge to succeed with CNC programming. Here are four tips to get you started:
Start with the fundamentals. You don't necessarily need to master G-code because a good CAM program will take care of the details for you. But it’s important to grasp the basics and structure of the programming.
Practice and repeat. Spend time writing and running G-code programs to get a feel for the language and build up your skills.
Seek guidance. The best way to learn is to learn from experts! You can find many resources online, including tutorials, textbooks, and forums. Or consider taking a course or workshop at your local community college or tech school.
- Be patient. You can’t expect to become a CNC whiz overnight. Give yourself the time to learn and improve. Enjoy the journey!
CNC Machining Is Worth the Exploration
Yes, CNC machining can be a challenging hobby.
But the benefits of creating parts with complex geometry at high precision are hard to ignore. Interested in both computer programming and working with your hands? Take a closer look at incorporating CNC machining into your skill set.
Don’t Forget the Finishing Touches
The more you do with CNC, the more you’ll need heat treatments (such as hardening or annealing) to provide the right properties for your pieces.
Many hobbyists send their work out to heat treating shops. But did you know you can save time and money by doing your own heat treating? Hot Shot Oven & Kiln offers a range of heat-treating ovens for machining. They're compact, easy to use, and feature Cool-to-Touch Technology for safe operation anywhere in your shop. Questions about your specific needs? Email Hot Shot or call us at 262-361-4912 for expert advice.