From prototyping to the creation of art to the manufacturing of products, machining, in general, has become more precise and efficient with the emergence of CNC machines. In addition to allowing for faster production, these tools automated many of the highly technical processes in machining and opened the door to crafting products that cannot be made manually.
The acronym “CNC” stands for “computer numerical control”. A CNC machine is a computer-controlled device that can cut, carve and mill programmed designs from wood, MDF, plastics, foams, and metals. In the process, a variety of tools are used, often with a wide range of cutting capabilities.
How CNC Machines Work
By reading digital codes from Computer-Aided Design (CAD) or Computer-Aided Manufacturing (CAM) software, CNC machines are able to follow a computer-controlled tool path as they cut or engrave a workpiece to turn a design into reality. During a given project, the workpiece is usually held down to the work table by clamps or a vacuum to keep it firmly in place as it is cut, while the rigid frame of the machine keeps vibrations to a minimum. Depending on the job, multiple cutting tools can be used, powered by a spindle that is programmed across one or more axes.
Compared to crafting by hand, CNC machines cut at a considerably higher speed and produce much smoother edge finishes. Users also have the ability to manipulate variables in a program, which helps immensely with meeting customer demands.
Types of CNC Machines
The specific CNC machine you need will vary depending on the job you plan to complete. The most common types of machines include:
This group includes router based milling machines. CNC Routers are dynamic machines capable of drilling, pocketing, edging, 3D cutting and more. CNC routers are the most common CNC machine and can be used in various industries such as Auto, Sign, Cabinetry, Furniture, Prototyping, Aerospace, Electronics, Stage Building etc. Routers are capable of cutting at up to 1200IPM (Inches Per Minute) with rapid movements up to 3000IPM.
CNC lathes produce highly precise cuts at a high velocity by spinning your workpiece against a cutting tool. Cuts are made as the machine moves its drill bit laterally until it touches the workpiece.
CNC Plasma Cutters
These tools use a combination of compressed-air gas and electrical arcs to generate a plasma torch that is used for cutting materials. CNC plasma cutters are most often used on metal.
CNC lasers can be used in a variety of capacities. CO2 lasers are most effective when cutting and engraving wood, acrylic, and leather, while fiber lasers provide fast, accurate cuts on sheets of metal. In addition, fiber markers are excellent for custom engraving on metal.
Electric Discharge Machines
By discharging electrical sparks, electric discharge machines mold workpieces into your desired shapes. These machines are often used for specialized mass production.
CNC Machine Applications
CNC machines are commonly used by hobbyists, small shops, and large industrial companies, which means they have an extensive range of applications. While smaller, individual projects may involve a project like engraving a custom sign, businesses may produce large quantities of furniture and cabinetry using this equipment.
Prototyping and the crafting of sophisticated artistic designs are also among the most popular uses of CNC machines, but the different types of products you can create are seemingly endless. From guitars, skis and surfboard racks to tables and aluminum composite panels, these machines can be used in a lot of ways.
Benefits of CNC Machines
When it comes to executing complex designs, CNC machines offer many advantages. One of the most obvious benefits is that they are extremely accurate; because the machines operate based on digital code fed to them from a computer, they complete the programmed jobs with near perfect precision. Programmers can also quickly and easily fix any mistakes rather than trying to do so manually.
For businesses in particular, CNC machines drastically improve efficiency because they allow for faster production. Not only do they automate processes that are labor intensive and time-consuming when done by hand, but they can more precisely create exact copies of a finished product at a rapid rate. This, in turn, makes it possible to generate more product at a cheaper price.
Another benefit that is often overlooked is cost reduction per product through greater material efficiency. By arranging cuts on a sheet and minimizing empty space, waste can be significantly reduced. This concept, known as nested machining, is the same as arranging cookie stamps on rolled-out dough in a way that makes the most cookies from a single roll.
CNC Machine Costs
Prices for CNC machines vary depending on the machine’s capabilities as well as its size. Quality beginner’s models typically start at a few thousand dollars, while commercial machines used for industrial manufacturing can easily exceed $100,000.
There are also plenty of options in between. Models regularly used in small shops that cut across three or four axes often cost at least $15,000, while machines constructed to cleanly cut materials that are otherwise difficult to work with — such as foam — tend to run in the $30,000-$70,000 range.
While some CNC machine packages come with most of the tools and accessories necessary for basic operation, it’s important to do your research and make sure you consider all costs. In many cases, much of the equipment you will need is sold separately from the machine itself.
History of CNC Machines
The first numerical control machines originated in the 1940s. Largely different from CNC equipment as we know it today, these early models included tools with motors attached that relied on punched tape, which was then used as a form of data storage.
By the 1960s, the introduction of minicomputers led to a drop in prices, which sparked the proliferation of CNC machines. In the years that followed, increased affordability broadened accessibility, making CNC popular among domestic toolmakers by the late ‘80s.
Today, CNC machines are commonly used both commercially and by hobbyists. Users are able to enjoy a large degree of freedom within a single program, making it easier than ever to create custom parts and quickly fix mistakes.