The CNC Machine is one of the most important machines in the manufacturing industry today. There are many types of CNC machines in the market today, and they differ in their mode of operation, cutting tool, materials, and the number of axes they can cut simultaneously.
In this article, we will provide the CNC machine definition, different types of CNC machines, and how to select the best CNC machines. So, read on 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 meaning comes from Computer Numerical Control. This machine makes creating or modifying parts easier with materials like metal, wood, plastic, and other materials. Besides, this is an automated system with three primary components; a drive/motion system, a feedback system, and a command function.
The CNC machine depends on digital instructions made by CAD and CAM software to function optimally. The CAD software makes the design, while the CAM converts the CNC design to a G-code which the CNC machine can read.
Additionally, their automated processing system often makes manufacturing parts faster and more accurate than manual machines.
Basic Elements of CNC Machine System
Below are elements or parts generally found in a CNC machine system.
- Information input/output devices include disk drives, special information devices, keyboards, and computers.
- Internet connection which could include Ethernet, HSSB (High-speed data transmission port), Processing LAN, RS 232C port, and other networks
- External mechanical shaft control unit, such as exchange bench, unloading, and loading robot, the drive shaft of the tool magazine
- Feed servo drive and motor unit
- Spindle motor and drive unit
- CNC control unit (numerical control part)
- PMC controller
- Feedback and position measurement unit of the machine
- Input and output unit of the control signal of the machine’s power cabinet
Different Types of CNC Machines
There are different CNC machine types ranging from milling, grinding, and drilling to plasma cutting. In this section, we’ll examine a list of CNC machine types and uses, as well as their application and limitations.
1. Mill CNC Machine
CNC milling machine types remove material from a workpiece and precisely shape it to the required specifications using high-speed cutting tools. Furthermore, milling machine cutter types come in a wide variety and serve various functions. A few common examples include end mills, reamers, face mills, taps, and drills.
However, the size it can machine depends on the enclosure size housing the machine and the highest distance the cutting tools can travel.
2. Lathe CNC Machine
The way CNC lathe machines operate is by rotating the material of the workpiece about a primary axis. The lathe cutting tools remove the material from the workpiece and shape it as needed.
CNC lathe machines are perfect for various tasks, including swiss machining, drilling, knurling, turning, and sanding. CNC machines in this category have applications in producing automobile parts, camshafts, crankshafts, musical instruments, gun barrels, baseball bats, and furniture.
However, due to the way this machine manufactures products, it is better to make symmetrical parts.
3. Drilling CNC Machine
The Drilling machine is one of the most popular CNC machines found in most CNC machine shops. Furthermore, the drilling CNC machine uses a specialized cutting tool called drill bits or drill. It is ideal for drilling holes in materials that hold screws, aesthetic requirements, or secondary assembly purposes.
Drilling CNC machines have applications in automobile manufacturing, astronautics, shipbuilding, mold making, engineering machinery, furniture making, and other wood works.
One major limitation of the machine is the dimension of the hole it can create. It is challenging to create holes that are deep or large enough without specialized drill bits.
4. Grinding CNC Machine
This machine uses a grinding wheel to remove materials from a workpiece. The grinding machine types function primarily for sanding, polishing, or finishing. The material used for making the grinding wheel could be ceramic-blend or diamond. However, you should know that diamond grinding wheels often provide high-quality secondary finishing.
However, this CNC grinding machine removes materials from a workpiece at a very slow rate. This is why it finds use primarily as a finishing or smoothening machine.
5. Laser Cutting CNC Machine
This CNC machine shapes products or parts using a highly focused laser beam. The laser beam cuts through the materials regardless of their conductivity to create the desired product or shape. Additionally, laser-cutting CNC machines have applications in three major industries: aerospace, automobile, and medical.
However, one of the limitations of a laser cutting CNC machine is the 2.75 inches maximum thickness of the material you can cut with it.
6. Plasma Cutting CNC Machine
A CNC plasma cutting device produces a very precise cut. It ionizes the air and melts the material in its path using an electrical discharge arc (similar to a plasma torch). The procedure only works with electrically conductive materials since it involves an electrical arc.
The plasma-cutting is a popular machine used in large-scale industries and hobbyist shops. It aids in industrial construction, automotive repair and restoration, and scrapping operations.
However, these machines produce tremendous heat as they cut materials by melting them. This heat often affects the surface finish of the cut material, resulting in heat-affected zones.
Another limitation is that this machine has a restrictive range of materials it can cut, as it only cuts through metals and other conductive alloys.
7. Waterjet Cutting CNC Machine
This machine cuts through materials using a thin jet of water. CNC water jet cutting is one of the most adaptable processes due to its capacity to cut through any material.
Waterjet cutting machine is quite versatile, as it can shape rubber, leather, fiberglass, nappies, circuit boards, foam, paper, ceramic, glass, stone, and sheet metal.
One of the biggest downsides is the waterjet cutting speed is slower than other cutting alternatives. This slower speed is especially evident around the curved cuts and corners.
8. EDM (Electric Discharge Machine)
The EDM uses an electrical arc to remove materials from a workpiece. It functions similarly to the plasma cutter. Besides, this machine produces parts through a non-contact process, and machines parts regardless of hardness.
Nevertheless, this machine works only on conductive materials like plasma cutting. In other words, you cannot use this machine to fabricate ceramics, wood, plastics, and other materials that do not conduct electricity.
9. CNC Router Machine
CNC routers can cut a variety of forms and patterns on flat surfaces of any material. The CNC router machine is used to fabricate musical instruments, signage, door carvings, moldings, and interior and exterior decorations.
However, the overall operation of the CNC router machine can be quite noisy due to its different 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 accurate parts. It also offers machinists greater machining flexibility. Besides, machines in this category range from 4-axis machines up to 12-axis machines.
Machines in this category are quite different from 2 and 3-axis machines and often require the expertise of a professional to function optimally.
11. 3D Printer
A 3D printer uses a digital file to create 3D solid objects. Unlike other processes discussed in this article, 3D printing is an additive manufacturing process. It is a process that successively creates products by adding materials to each other.
However, the cost of procuring this CNC equipment and manufacturing components using this process are quite high. Also, 3D printing speed is slow, especially when used for mass production processes.
12. CNC Automatic Tool Changer
Also known as ATC is a variation of different types of CNC machines. However, what this machine does is automatically change the machine cutting tool. This increases the production speed and reduces lead time.
The ATC carries out this switch for two major reasons: replacing a broken or worn-out tool and swapping out a wrong tool for the right one.
Types of CNC Machines by Number of Coordinate Axes
Here are the different types of CNC machines according to the number of Axes traveled by the machine.
2-Axis CNC Machines
The most fundamental 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 produce precise straight cuts, drill holes in boards, or process just one workpiece surface without moving it.
3-Axis CNC Machines
The most prevalent kind of CNC machine is the 3-axis machine. Like the 2-axis machines, machines in this category also work on immobile workpieces. These machines can work on the fundamental pieces in 2.5 dimensions. 3-axis CNC machines move in the conventional X and Y axis, with an additional Z axis for depth.
4-Axis CNC Machines
This machine has an A-axis, known as the axis of rotation, and the X, Y, and Z axes. This axis enables the rotation of the cutting tool along the X-axis. Cutouts and arc cutting are also excellent uses for these machines.
5-Axis CNC Machines
5-axis CNC provides the cutting tool with a pivoting motion along an axis called the C-axis. The C-axis is the axis on which turning and pivoting occur.
These machines can machine five surfaces of material concurrently with the work surface remaining stationary, which allows them to produce intricate and precise parts. These machines are extremely helpful in making equipment used in the medical industry because of their excellent accuracy.
7-Axis CNC Machines
On CNC machines in this category, there are seven axes: three conventional axes for the workpiece’s rotation, three for the cutting tool’s movement, and one for the arm’s rotation, known as the E-axis, this axis.
Due to the complexity of the parts they can make, these machines frequently produce aeronautical, medical, and military equipment.
9-Axis CNC Machines
A combined CNC system with a 5-axis milling machine and a 4-axis lathe machine is a 9-axis CNC machine. The lathe completes the workpiece’s internal features, while the milling machine works on the surface to achieve the necessary surface finish.
For this reason, it is easier to produce interior and external parts’ features using a 9-axis machine. Dental implants, medical instruments, and sophisticated aircraft equipment can all be produced using these devices.
12-Axis CNC Machines
The 12-axis machines have two cutting heads that can move in X, Y, Z, A, B, and C axes. These machines increase production speed while also increasing precision by orders of magnitude.
Types of CNC Machines According to Moving Trail
Below are the types of CNC machine systems according to the moving trail.
In a point control system, the moving components of CNC machines are only controlled precisely from one point to another without being machined in the process. If simultaneous positioning is not required, this positioning is the most cost-effective system that you can use for reverting, tapping, spot welding, and drilling.
Together with precisely arranging the moving components of CNC machines from one location to another, linear control systems also regulate the pace and trajectory of movement between two connected sites.
With a parallel coordinate axis, this control ensures linear cutting movement. This is why they often finds application in simple CNC milling and grinding machines.
The workpiece moves following the programmed trajectory and speed relative to the cutter under the control of the contouring control system, which also coordinates the motion of multiple feed shafts simultaneously. This allows for continuous cutting to occur while the movement is being made.
Contour control makes processing plane curves or spatial surface contours easier. It finds application in CNC grinders, milling, and turning machines.
Types of CNC Machines Divided by Servo System
Here are the types of CNC machine systems according to Servo.
Open Loop Control System
A detection and feedback device is not present in an open-loop control system. The driving circuit amplifies the power before the CNC device’s instruction signal, which is transmitted in a single direction, drives the stepping motor that moves the machine table.
One benefit of the open-loop control system is its low pricing, which makes it affordable. On the downside, it has poor accuracy and stability, reducing the work quality.
Semi-Closed Loop Control System
The worktable’s actual displacement is calculated using a semi-closed loop control system’s angular displacement detection device installed directly at the end of the servo motor shaft or ball screw.
This device compares the calculated value with the worktable’s original instruction displacement value and then controls using the difference. This system’s pricing is moderate, but precision and stability are high.
Closed-Loop Control System
A closed-loop control system uses a linear displacement-detecting device mounted on the machine tool’s moving parts or tabletop. The CNC device’s comparator receives the actual displacement discovered and compares it to the value of the program instruction.
Controlling the stability of a closed-loop control CNC machine is quite difficult. However, this machine guarantees high precision.
How to Select the Best CNC Machine Type?
When selecting the ideal CNC machine for your company, there are numerous things to consider. The CNC machine appropriate for your needs depends on the type of business you run, the items you create, and the production volume. Below are factors to consider when selecting a CNC machine.
Your business type will reduce the alternatives available to you. For instance, if you own a small CNC machine shop, you only need a few CNC routing machines. On the other hand, if you manage a sizable manufacturing company, you’ll probably require larger and multi-function machines.
Availability of Spare Parts
The CNC machine could wear out or malfunction just like any other machine. So, ensure the brand or model you buy can be quickly repaired by your specialists and that spare parts are accessible for replacement before you buy them. The reason is that readily available parts determine how long you would have to wait before you begin production again.
The CNC machine you will need will mostly depend on the work done. A CNC lathe or 3-axis milling machine may be sufficient for simple items. Yet, when intricacy rises, it becomes cheaper to have machinery that can fabricate most of the pieces in a single setup. The finest machines for this kind of work are five-axis CNC machines.
Also, some product categories demand specialist CNC equipment. For instance, a purpose-built Swiss lathe will be great for producing thousands of tiny, intricate, cylindrical pieces.
Know the Power Requirements
These machines require a lot of power and frequently use three-phase power to function optimally. Thus, ensuring the building receives enough power to run the new equipment is crucial. Confirming current power use is also worthwhile. When all of the current machines are operating, there might be ample power supplied to the facility, but adding a new CNC could increase usage above the amount of supply.
The Materials To Be Machined
The type of material being processed is an essential consideration When choosing CNC machines. Machines must be robust enough to mill precise pieces from hard alloys. Precision machines that can maintain the necessary tolerances can be considered for softer materials like mild steel.
WayKen: CNC Machining Service for Every CNC Project
While a CNC machine is mostly a straightforward process, choosing the ideal one for your needs becomes a daunting task. Also, CNC machines are quite expensive, so even if you have one in mind, affording the high initial investment might be difficult.
But there is an alternative. You can outsource your CNC machining service to industry manufacturers like WayKen. At Wayken, we have an array of CNC machines ranging from simple 3-axis machines to multi-axis machines for all your needs. Our team of specialized engineers is always available to handle your product needs regardless of their intricacy.
So why wait? Contact us today, so we can start working on your CNC projects.
Are CNC machines expensive?
A CNC machine is an expensive investment. However, the machine justifies its cost with its high precision and tolerance level.
What are the main components of a CNC machine?
A computer numerical control (CNC) system comprises three basic components: the processing apparatus, also referred to as a machine tool, the machine control unit, and CNC software, which is a collection of instructions.
What is the most common CNC machine type?
The CNC milling machine is one of the most common CNC machine types, as it has a variety of applications ranging from tapping to turning.