The CNC machine is one of the most important machines in the manufacturing industry today. There are many types of CNC machines on the market today, and they differ in the way they work, the cutting tool, the materials, and the number of axes they can cut at the same time.
In this article, we will explain the definition of a CNC machine, different types of CNC machines, and how to choose the best CNC machine. So keep reading to get this great information.
What is a CNC machine?
A CNC machine is a computer-controlled device that facilitates the manufacturing of parts and products. The acronym CNC stands for Computer Numerical Control. This machine makes it easy to create or modify parts from materials such as metal, wood, plastic and other materials. It is also an automated system with three main components: a drive/motion system, a feedback system and a command function.
For the CNC machine to function optimally, it relies on digital instructions from CAD and CAM software. CAD software creates the design while CAM converts the CNC design into G-code that the CNC machine can read.
Additionally, its automated processing system allows parts to be manufactured faster and more accurately than manual machines.
Basic elements of CNC machine system
Below are the elements or parts generally found in a CNC machine system.
- Information input/output devices include floppy disk drives, specialized information devices, keyboards, and computers.
- Internet connection, which may include Ethernet, HSSB (high-speed data transfer port), processing LAN, RS 232C port, and other networks
- External mechanical shaft control unit such as changer, unloading and loading robot, tool magazine drive shaft
- Power servo drive and motor unit
- Spindle motor and drive unit
- CNC control unit (numerical control part)
- PMC Control
- Machine position and feedback measuring unit
- Machine power cabinet control signal input and output unit
Different Types of CNC Machines
There are different types of CNC machines, from milling machines, grinding machines and drilling machines to plasma cutting machines. In this section, we look at a list of CNC machine types and applications, as well as their applications and limitations.
1. CNC milling machine
CNC milling machine types remove material from a part and precisely shape it to required specifications using high-speed cutting tools. In addition, there is a wide variety of types of cutters for milling machines that perform different functions. Some common examples are end mills, reamers, face mills, taps, and drills.
However, the size to be machined depends on the size of the housing in which the machine is located and the maximum distance the cutting tools can travel.
2. CNC lathe
CNC lathes work by rotating the workpiece material around a main axis. Rotary cutting tools remove material from the workpiece and shape it as needed.
CNC lathes are perfect for a variety of tasks, including turning, drilling, knurling, turning, and Swiss-type grinding. CNC machines in this category are used in the production of automotive parts, camshafts, crankshafts, musical instruments, gun barrels, baseball bats and furniture.
However, because of the way this machine makes products, it is better at making symmetrical parts.
3. CNC Drilling Machine
The drill press is one of the most popular CNC machines found in most CNC shops. Furthermore, the CNC drill press uses a special cutting tool called a drill or bit. It is ideal for drilling holes in materials that contain screws, for aesthetic purposes or for secondary assembly.
CNC drill presses are used in automobile manufacturing, aerospace, shipbuilding, mold making, mechanical engineering, furniture manufacturing and other wood processing industries.
A major limitation of the machine is the size of the hole it can create. Without special drill bits, it is difficult to create holes that are deep or large enough.
4. CNC grinding machine
This machine uses a grinding wheel to remove material from a workpiece. Types of grinding machines are mainly used for grinding, polishing or finishing. The material used to make the grinding wheel can be a ceramic or diamond mixture. However, you should know that diamond grinding wheels generally provide high-quality secondary finishing.
However, this CNC grinding machine removes material from a part very slowly. For this reason, it is mainly used as a finishing or straightening machine.
5. CNC laser cutting machine
This CNC machine shapes products or parts using a highly focused laser beam. The laser beam cuts materials, regardless of their conductivity, to create the desired product or shape. Furthermore, CNC laser cutting machines are used in three main industries: aerospace, automotive and medical.
However, one of the limitations of a CNC laser cutting machine is the maximum thickness of 2.75 inches of material you can cut with it.
6. CNC Plasma Cutting Machine
A CNC plasma cutter produces a very precise cut. It ionizes the air and melts material in its path using an arc of electrical discharge (similar to a plasma torch). The process only works with electrically conductive materials because it creates an electrical arc.
Plasma cutting is a popular machine used in large-scale industry and hobby workshops. Helps with industrial construction, repair and restoration of motor vehicles and dismantling work.
However, these machines generate enormous heat when fusing cutting materials. This heat often affects the surface finish of the material being cut, resulting in heat affected zones.
Another limitation is that this machine can only cut a limited range of materials, as it only cuts metals and other conductive alloys.
7. CNC Waterjet Cutting Machine
This machine cuts materials using a fine jet of water. CNC waterjet cutting is one of the most adaptable processes because it can cut any material.
Waterjet cutting machines are very versatile as they can shape rubber, leather, fiberglass, diapers, circuit boards, foam, paper, ceramics, glass, stone and sheet metal.
One of the biggest disadvantages is that the waterjet cutting speed is slower than other cutting alternatives. This slower speed is particularly noticeable in cuts and curved corners.
8. EDM (Electrical Discharge Machine)
EDM uses an electric arc to remove material from a workpiece. It works similar to a plasma cutter. Furthermore, this machine produces parts using a non-contact process and processes parts regardless of their hardness.
However, this machine only works on conductive materials such as plasma cutting. In other words, you cannot use this machine to make ceramics, wood, plastic and other materials that do not conduct electricity.
9. CNC milling machine
CNC routers can cut a variety of shapes and patterns on flat surfaces made from any material. The CNC milling machine is used to produce musical instruments, signs, door carvings, moldings, and indoor and outdoor decorations.
However, the overall operation of the CNC milling machine can be quite noisy due to its various components.
10. Multi-axis CNC Machine
This CNC machine can move in four or more directions or axes. Compared to a two- or three-axis machine, multi-axis machining is more complex and produces more precise parts. It also offers machinists more flexibility during machining. Furthermore, machines in this category range from 4-axis to 12-axis machines.
Machines in this category differ significantly from 2- and 3-axis machines and often require the expertise of a professional to function optimally.
11. 3D Printers
A 3D printer uses a digital file to create three-dimensional solid objects. Unlike the other processes discussed in this article, 3D printing is an additive manufacturing process. This is a process in which products are created successively by adding materials to each other.
However, the cost of purchasing this CNC equipment and manufacturing components through this process is quite high. Furthermore, 3D printing speed is slow, especially in mass production processes.
12. CNC Automatic Tool Changer
Also known as ATC, it is a variation of different types of CNC machines. However, this machine automatically changes the machine's cutting tool. This increases production speed and reduces lead time.
ATC performs this exchange for two main reasons: to replace a broken or worn tool and to exchange an incorrect tool for the correct one.
Types of CNC machines by number of coordinate axes
Here are the different types of CNC machines according to the number of axes moved by the machine.
2 axis CNC machines
The most basic CNC systems available are 2-axis CNC machines. Machines in this category move in the X-axis (horizontal) and Y-axis (vertical).
Typically, these machines make precise straight cuts, drill holes in plates, or machine just one surface of the part without moving it.
3 axis CNC machines
The most common type of CNC machine is the 3-axis machine. Just like 2-axis machines, machines in this category also work on stationary parts. These machines can work on the basic parts in 2.5 dimensions. 3-axis CNC machines move in the traditional X and Y axes, with an additional Z axis for depth.
4 axis CNC machines
This machine has an A axis, called the rotary axis, as well as the X, Y, and Z axes. This axis allows the cutting tool to rotate along the X axis. Cutouts and curved cuts are also excellent uses for these machines.
5 axis CNC machines
5-axis CNC offers the cutting tool with a rotary motion along an axis called the C-axis. The C-axis is the axis on which rotation and pivoting occur.
These machines can process five material surfaces simultaneously while keeping the work surface stationary, allowing them to produce complex and precise parts. These machines are extremely useful in manufacturing equipment for the medical industry due to their excellent precision.
7 axis CNC machines
In CNC machines in this category there are seven axes: three conventional axes for rotating the part, three for moving the cutting tool and one for rotating the arm, the so-called E axis.
Due to the complexity of the parts they can produce, these machines are widely used in the production of aeronautical, medical and military equipment.
9 axis CNC machines
A CNC system combined with a 5-axis milling machine and a 4-axis lathe is a 9-axis CNC machine. The lathe completes the internal features of the part, while the milling machine processes the surface to obtain the desired surface finish.
For this reason, it is easier to produce internal and external part features with a 9-axis machine. Dental implants, medical instruments, and sophisticated aircraft equipment can be manufactured using these devices.
12 axis CNC machines
12-axis machines have two cutting heads that can move in the X, Y, Z, A, B and C axes. These machines increase production speed many times over and, at the same time, accuracy.
Types of CNC machines by motion path
Below are the types of CNC machine systems according to the trajectory.
Check Point
With a point control system, the moving components of CNC machines are precisely controlled only from one point to another without being processed. When simultaneous positioning is not necessary, this positioning is the most economical system you can use for turning, threading, spot welding and drilling.
Linear control
In addition to precisely arranging the moving components of CNC machines from one location to another, linear control systems also regulate the pace and trajectory between two connected locations.
This control guarantees a straight cutting movement with parallel coordinate axes. Therefore, it is often used in simple CNC milling machines and grinding machines.
Contour control
The workpiece moves according to the programmed path and speed relative to the cutter under the control of the path control system, which also coordinates the movement of multiple feed spindles at the same time. This allows for continuous cutting while moving.
Contour control makes it easy to edit planar curves or spatial surface contours. It is used in CNC grinding machines, milling machines and lathes.
Types of CNC machines divided by servo system
Here are the types of CNC machine systems according to the servo.
Open control system
In an open control system there is no detection and feedback device. The drive circuit amplifies power before the unidirectional command signal from the CNC device drives the stepper motor that moves the machine table.
An advantage of the open control system is its low price, which makes it accessible. On the other hand, there is a lack of precision and stability, which reduces the quality of work.
Semi-closed control system
The actual displacement of the work table is calculated using an angular displacement detector of a semi-enclosed control system installed directly at the end of the servo motor shaft or ball screw.
This device compares the calculated value with the original displacement value of the work table and then controls based on the difference. The price of this system is moderate, but the accuracy and stability are high.
Closed control system
A closed-loop control system utilizes a linear displacement sensing device mounted on the moving parts or table of the machine tool. The comparator of the CNC device receives the actual detected displacement and compares it with the program instruction value.
Controlling the stability of a closed-loop CNC machine is quite difficult. However, this machine guarantees high precision.
How to choose the best type of CNC machine?
There are many things to consider when choosing the right CNC machine for your business. Which CNC machine is right for your needs depends on the type of business you have, the items you produce, and the volume of production. Below are factors to consider when choosing a CNC machine.
Company type
Your type of business limits the alternatives available to you. For example, if you have a small CNC workshop, you will only need a few CNC milling machines. On the other hand, if you run a larger manufacturing company, you will likely need larger, multi-functional machines.
Availability of spare parts
The CNC machine, like any other machine, can suffer from wear and tear or malfunction. Therefore, before purchasing, make sure that the brand or model you are purchasing can be quickly repaired by its experts and that spare parts are available for replacement. The reason for this is that readily available parts determine how long you will have to wait before starting production again.
Product Requirements
The CNC machine you need mainly depends on the work to be done. For simple parts, a CNC lathe or 3-axis milling machine may be sufficient. However, as complexity increases, it becomes cheaper to have machines that can produce most parts in a single operation. The best machines for this type of work are 5-axis CNC machines.
Additionally, some product categories require specialized CNC equipment. For example, a custom Swiss lathe is ideal for producing thousands of tiny, complex cylindrical parts.
Know your power requirements
These machines require a lot of energy and generally use three-phase power to function optimally. Therefore, it is important to ensure that the building receives enough electricity to run the new equipment. It's also worth checking your current energy consumption. When all current machines are running, the facility may receive sufficient power, but the addition of a new CNC may cause consumption to exceed the amount supplied.
The materials to be processed
When selecting CNC machines, the type of material to be processed is an important consideration. Machines must be robust enough to mill precise parts from hard alloys. For softer materials such as carbon steel, precision machines that can maintain the required tolerances may be considered.
WayKen: CNC machining service for any CNC project
While purchasing a CNC machine is generally straightforward, choosing the ideal machine for your needs can become a difficult task. Additionally, CNC machines are quite expensive, so even if you are considering one, it may be difficult to afford the large initial investment.
So what are you waiting for? Contact us today so we can start working on your CNC projects.
Common questions
Are CNC machines expensive?
A CNC machine is an expensive investment. However, the machine justifies its price due to its high precision and tolerance.
What are the main components of a CNC machine?
A computer numerical control (CNC) system consists of three basic components: the processing device, also called the machine tool, the machine control unit, and the CNC software, which is a collection of instructions.
What type of CNC machine is most common?
The CNC milling machine is one of the most common types of CNC machines because it has a wide range of applications, from thread cutting to turning.
