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CNC stands for computer numerical control, and this describes a machine which is controlled by a computer based on a coordinate system. CNC machines are not new, and have been around since the 1950's. Early CNC machines were essentially modified traditional machines, like mills or turning centers, with electric motor control so they could be operated using a numerical system.
But even today, modern CNC machines still use very similar systems and operate much like traditional manufacturing techniques, though modern technology has made CNC machines safer, more precise, and more affordable than they used to be.
In this article, we'll be comparing common CNC machines that you might be considering for your own DIY projects, rapid prototyping, or small-scale production needs, as well as why you might choose one type of CNC machine over another.
3D Printers are one of the most common types of CNC machines used today, but they are often not referred to as CNC machines. However, 3D printers operate by following a coded file that instructs the printer how to move and manufacture our designs.
3D printers work through an additive manufacturing process, where material is added (layer by layer) to create our parts. Two benefits of this production technique are that there is little waste, and that complex geometries can be manufactured depending on the resolution of the 3D printer being used.
There are many different types of 3D printers out there, some that extrude rolls of material called filament, and others that cure liquid resin using a light source. Some 3D printers are more affordable, and some can produce higher quality and stronger parts. 3D printers typically manufacture parts using some type of plastic or plastic composite, though versatile material options are becoming more readily available as this technology improves.
CNC Milling Machines are one of the most commonly used CNC machines in an industrial setting, as well as for hobby and prototyping use. Milling machines utilize a milling spindle that rotates a cutting tool at high speeds, and then uses this cutting tool to carve material through a subtractive manufacturing process.
Unlike an additive process, subtractive manufacturing requires us to start with a raw piece of material such as aluminum or wax - then uses milling operations to create pockets, contours, holes, and other types of engravings or cuts to fabricate our designs.
CNC Mills come in many different configurations, from smaller desktop units to large industrial machines. Mills are also typically more versatile than other CNC machines, with some mills being able to manufacture parts out of metals, plastics, composites, and woods - like the Carvera and Carvera Air And the complexity of the type of part you can create with a mill will be determined by the mill's resolution, power, and number of axis.
CNC Routers are in many ways very similar to a CNC Milling machine as both use a rotating cutting tool to manufacture parts through a subtractive manufacturing process. But while CNC Mills use a high speed spindle, Routers use a slower spinning router similar to what you might find in a woodshop.
Routers are often a bit more affordable than mills as they are typically not capable of achieving the same level of detail or precision. But routers are also often much larger than mills, not enclosed, and primarily used for machining wood and softer materials.
Sometimes referred to as turning centers, a CNC Lathe is another machine that operates through a subtractive manufacturing process. Unlike a typical Mill or Router, the material is rotated on a spindle in a Lathe while the cutting tool does not rotate but moves side to side.
A CNC Lathe then cuts away excess material to manufacture our designs through a symmetrical turning process. Lathes are commonly used to make spindles or bolts and screws out of wood and metals, and are also one of the fastest CNC machines available.
While a Lathe is fundamentally different from a CNC Mill, CNC Mills with 4 or 5 axis can sometimes replicate similar production processes as a CNC Lathe.
CNC Lasers also come in many forms, and like a CNC Mill or Router, we start with a piece of raw material. All lasers then use a light source to cut or engrave materials, typical wood, fabric, or plastic.
Some lasers use a diode as the light source, which is ideal for engravings but not capable of cutting through thicker materials. More industrial CO2 and Fiber lasers offer better performance for manufacturing with thicker materials or at higher speeds. Industrial lasers can also work with a wider range of materials, some can even engrave metals too.
But a key safety concern that you must consider with lasers is ventilation, as all laser cutters and engravers release harmful fumes as a byproduct of this manufacturing process. As such, it's important to ensure you're working with materials that are safe to use for a laser, and also have proper exhaust and air filtration systems in place.
There are many other types of CNC machines out there, some which are suitable for hobby and DIYers like vinyl cutters or embroidery machines, and others which are used in industrial settings like water cutters and wire EDM machines.
But for whichever CNC machine you find yourself working with, it's important to note that the core operation across all of these machines is typically quite similar in nature. All CNCs can move across different axis using a combination of rails or rods, and stepper or servo motors to move.
What makes the machine unique are the types of control systems that are used, as well as the tool head. For example 3D printers are sometimes built similarly to laser cutters or mills, but one has an extruder while the other has some type of spindle or laser module. This is why you can often find versatile machines that can perform many different operations, like the Carvera and Carvera Air desktop CNCs.
Now that we've covered the different types of CNC machines, let's discuss how to manufacture our designs using a CNC. For whichever type of machine you choose, you'll need to start with a design. This can sometimes be a picture or a 3D model, or perhaps a Gerber file for a PCB. We typically use CAD (Computer Aided Design) software to make these designs, though you can also find and purchase ready-made designs across the web.
The next step will vary slightly depending on the type of CNC machine you're using - which is preparing our designs in CAM (Computer Aided Manufacturing). CAM Software is where we need to adjust the settings for our CNC machine depending on the production process and material that we're using to create our parts.
3D printers use Slicers, a specialized CAM software that "slices" 3D models into layers to be manufactured through additive techniques. In a slicer, you usually just need to set your print resolution and the type of material you might be working with like PLA or TPU, etc.
But for other types of CNC machines, including Mills, Routers, Lathes, and Lasers, we use CAM to create Tool Paths. Tool Paths instruct our CNC machines on how to move and cut our parts using the correct speed and feed parameters for the tools and materials we've selected. These settings are crucial, and ones that we look at deeper in our other articles and guides.
The output file of CAM software is a coded file that instructs the CNC machine how to move and create our parts. This coded file is typically written in Gcode.
So how do you pick between these different types of machines and production processes? Its first important to consider that you might find yourself needing more than one production technique to create your designs. In this case, you might consider selecting a few machines based on your budget, or choose a CNC that is more versatile than others.
CNC Mills like the Carvera and Carvera Air can work with a wide range of materials, including metal, wood, plastic, and composites. These mills can also be equipped with a 4th axis and laser modules to manufacture a much wider range of parts too - from prototyping to production needs.
3D Printers typically work with fewer material types, and are primarily used for prototyping rather than production. But 3D printers are often a bit more affordable, smaller, and quieter than the other CNC machines we've looked at, making them suitable for more entry-level users and beginners.
Laser Cutters and Engravers are typically quick and great for cutting or engraving flat material for decorative and ornate projects. But as mentioned earlier, you need to ensure that proper ventilation equipment is also purchased when using this type of machine.
We recommend you first consider the type of project you're looking to create, as well as the types of materials you want to work with. From there, choose a CNC that fits your needs, your budget, and your workspace while also offering you the tools you need to bring your ideas to life!
So CNC machines aren't new, but newer technological innovations like AI have made modern CNC machines more capable and easier to use than ever before. CNC Machines also now come in much greater variety, allowing makers of all styles to find something that suits their needs and their budgets with greater ease.
Before you choose, do your research and make sure you're picking a machine that offers tools to help you learn and find greater success in your projects and creations! To learn more about CNC machines, check out our Getting Started video series.
