CNC, or Computer Numerical Control, has been the main pillar on which Industry 3.0 was built. CNC technology provides the opportunity for manufacturing processes that can meet the astronomical figures of production.
Due to the vast benefits of CNC technology, it finds applications in almost every manufacturing industry out there regardless of scale. Manufacturers are always on the lookout for new CNC technologies and machines that they can utilize to speed up production even more and save costs.
In this article, we will go through the different types of CNC machining technologies. We will also go through the types of machines, classified on the basis of multiple factors.
Without any further ado, let us dive into the topic right away:
What is CNC Machining?
Computer Numerical Control machines (CNC machines) allow the ability to automate industrial manufacturing processes. These machine tools do all the work that was traditionally done by hand such as shaping and processing of materials.
These machines work on an algorithm written by designers that instruct the machine tools on where to move, how to operate and control other secondary processes of the machines. A CNC machining process is highly scalable and can create anything from small electronic components to large scale aircraft and aerospace parts.
What are the Different Types of CNC Machines?
As we will learn in the sections to come, there are multiple ways to classify a CNC machine. The most basic classific is done according to the design and function of the CNC machine. According to this classification, CNC machining is of the following types:
CNC Milling Machine
CNC milling machines use cutting tools to remove material from a workpiece and shape it accurately to the required specifications. The workpiece is usually fixed on a location while the high-speed rotating cutting tool removes material from it.
CNC mills can have a wide range of cutting tools, each having a different cut shape. Some common cutting tools are end mills, reamers, face mills, taps, drills, and more. These machines come in both vertical and horizontal operating construction.
Applications of CNC Milling Machines
Some common applications of CNC machining are:
- Prototype models
- Musical Instruments
Limitations of CNC Mills
CNC milling is a widely adopted technology since it fulfills its purpose quite successfully, providing high-speed manufacturing with precision CNC machining. Some of the factors that can be considered a limitation to certain users are:
- Size Limitation: Any particular CNC milling machine will have a limitation on the size of the part that you can machine with it. This size usually depends on the maximum travel distance of the tools and the size of the enclosure.
- Operator Skill: CNC mills require operators to have a good skill set in the field and the machines. A small operator error can lead to significant errors in accuracy and design problems in the later stages.
- Cost: Some users see the relatively high initial cost of a CNC milling machine as a limitation of the method. However, it is important to note that the high cost also brings several benefits with it such as accuracy and precision CNC machining, which other alternatives do not provide.
When it comes to the cost of a CNC milling machine, the range is wider than you might imagine. There are significantly cheaper options for home use that can be found for as low as $10,000. On the other hand, it is common to see milling machines in production workshops costing over $200,000.
The hourly cost of CNC milling depends on the axis of the machine. 3-axis machines can cost around $40 per hour, the price going up to $200 per hour for higher-axis machines.
CNC Router Machines
CNC routers are used to cut various shapes and designs on flat surfaces of any material. These machines replace multiple manual tools traditionally used in carpentry and metalworking workshops, such as boring machine tools, panel saws, and spindle molders.
Applications of CNC Routers
Due to the ability of CNC routers to cut intricate shapes, its applications include:
- Carved wood furniture
- Interior and Exterior decorations
- Door carvings
- Musical instruments
Limitations of CNC Routers
- High noise: CNC routers are usually fitted with parts like a spindle, extraction system, and vacuum system. The overall operation of the machine can create a high noise level.
- Residual Dust: The working environment of CNC routers contains a high amount of wood dust or metal dust.
Cost of CNC Routing Machines
On average, the initial price of the CNC routing machine varies between $3000 and $100,000. The hourly rates of these machines are the same as a CNC milling machine.
CNC Plasma Cutters
CNC plasma cutting is a highly accurate cutting process. It uses an electrical discharge arc to ionize the air and melt the material where the arc is struck. Since it works through an electrical arc, the process only applies to electrically conductive materials.
Applications of CNC PLasma Cutters
- Automobile manufacturing
- Automotive repairs
- Fabrication shops
- Salvage and Scrapping
Limitations of CNC Plasma Cutters
- Materials: Plasma cutting only cuts through metals and conductive alloys. This limitation is a deal breaker for users who wish to machine materials like wood and plastics.
- Heat-Affected Zones: Plasma cutting is a hot cutting process that works by melting the material. This leaves visually visible heat-affected zones (HAZ) on the cut area.
Cost of CNC Plasma Cutters
The initial cost of CNC plasma cutting machines lies between $12,000 and $300,000. The hourly cost of these machines is around $20 per hour.
CNC Lathes and Turning Machines
CNC lathe machines work by revolving the workpiece material around a central axis. Cutting tools are then applied to the workpiece to remove material and shape it into the required product by the CNC lathe machine.
CNC lathe machines are used for a variety of processes like cutting, sanding, facing, drilling, turning, knurling, etc. In CNC turning, a non-rotary cutting tool moves linearly on a rotating workpiece to create a helix cutting path.
Applications of CNC Lathes and Turning Machines
A CNC lathe machine finds applications in almost every manufacturing industry, for making tools such as:
- Automobile parts
- Gun barrels
- Baseball Bats
- Musical Instruments
- Dining tables
- Furniture legs
Limitations of CNC Lathes and Turning Machines
- Symmetrical Nature: CNC lathes in general can only create symmetrical components due to the way they shape materials. Therefore, these machines fail when custom, asymmetrical shapes are required.
Cost of CNC Lathes and Turning Machines
The initial machine price of CNC lathes starts at around $15,000 and keeps going up depending on machine specs. The hourly rate for a CNC lathe starts at around $40 per hour.
CNC Laser Cutting Machine
CNC laser cutters utilize light rays for cutting sheets of any material. A CNC laser cutter machine is one of the most accurate cutting processes out there, with a precision higher than even plasma cutting. CNC laser cutters are not limited to conductive materials as they can cut any material type.
Applications of CNC Laser Cutters
- Aerospace parts
- Automobile frames
- Medical Equipment
- Engrave materials
Limitations of CNC Laser Cutters
- Limited Thickness: Laser cutting machines are limited to the maximum thickness of the material you can cut with them.
- Technical Expertise: Laser cutting machines require highly technical operators to work with them. These machines deal with the high-powered laser which can reflect back, so a skilled operator is required to know how to control them properly.
Cost of CNC Laser Cutting Machine
The cost of buying a laser cutting machine can vary between $5000 and $300,000. The hourly cost of these machines is about $20 per hour.
CNC Electrical Discharge Machines (EDM)
Electrical Discharge Machines (EDM) work similar to plasma cutters by using an electrical arc to remove material at the required location. This method is useful for creating fast 2D cuts on metal sheet format.
Applications of CNC Electrical Discharge Machines
- Manufacturing Injection Molds
- Die Casting
- Blanking Punches
Limitations of CNC Electrical Discharge Machines
- Material Constraints: CNC EDM machining works only for conductive materials. You cannot use this method for machining plastics, ceramics, wood, or any other non-conductive material.
- Slow Cutting Rate: EDM cutting is very slow on corners and curves due to high electrode wear. This leads to increased costs as well as slow overall production.
Cost of CNC EDM Cutting
The cost of a new EDM cutting machine starts at $15,000. The hourly cost of these machines is about $25 per hour, with the cost of electrode wire accounting for a major portion of the hourly cost.
CNC Waterjet Cutting Machine
A waterjet CNC machine utilizes a very thin stream of water to cut through any material. It is one of the most versatile cutting methods due to its ability to work on any material type. Higher-axis waterjet cutters are capable of 3D cuts as well. Additionally, the thickness of material suitable for waterjet cutting is quite high.
Applications of CNC Waterjet Cutting
- Foam cutting
- Paper cutting
- Textile Cutting
- Metal block cutting
Limitations of CNC Waterjet Cutting
- Cutting time: Waterjet cutting is a slower cutting process than other alternatives. The speed is especially slower around corners and curved cuts.
- Component Breakdown: Waterjet cutters work by using ultra-high pressure jets. If using a low-quality waterjet system, there is a possibility of the components of the cutter breaking down.
Cost of CNC Waterjet Cutters
Waterjet cutters have a wide price range, starting at about $50,000 and going up to $200,000. The hourly cost of these machines ranges from $15 to $30 per hour, with the cost of abrasive accounting for the major fraction of the total hourly cost.
CNC Grinding Machines
CNC surface grinders use a rotating grinding wheel to remove workpiece material for sanding, finishing, or polishing purposes. Grinding is usually applied as a secondary process for finishing touches.
Applications of CNC Grinders
- High precision gear
- Automobile parts
- Medical equipment
- Aerospace parts
Limitations of CNC Grinders
- Slow Process: CNC grinding is a slow process since removing material takes place at a very slow rate. This makes it unusable for any application to shape materials and only works for finishing and smoothing out the surfaces.
Cost of CNC Grinders
CNC grinders are relatively cheaper than other CNC machines. The cost of these machines starts at $5000. The cost of operating these machines comes to about $20 per hour.
CNC Drilling Machine
A CNC drilling machine is one of the most common types of CNC machining process in workshops. It is used for drilling holes in any material for the purpose of screws, secondary assembly, or aesthetic requirements.
Applications of CNC Drilling Machine
- Automobile manufacturing
- Engineering Machinery
- Mould making
- Woodworking and furniture making
Limitations of CNC Drilling Machine
Dimensions of the Hole: The dimensions of a hole by CNC drilling are limited. This method cannot be used to create very deep holes or very large holes. Additionally, different diameters of drill holes require different drill bits.
Cost of CNC Drilling Machines
The cost of CNC drilling machines is about $25,000 on average.
Automatic Tool Changer
Automatic Tool Changer (ATC) is a variant for all the common types of CNC machines. This ability allows for automated changing of the cutting tool of the machine, leading to faster production and lower downtimes.
ATC is used to switch the type of cutting tool in a CNC machine, or to replace a broken or worn-out tool. It increases the degree of automation in the manufacturing process. Change of tooling is one of the major bottlenecks in most CNC machines, so ATC improves the capability of any CNC equipment.
Types of CNC Machines Based on Number of Axes
Once the type of CNC machine is fixed, the particular equipment can be further segmented on the basis of the number of axes. For instance, a CNC milling machine can come in a 3-axis, 4-axis, and 5-axis variant and the price and capability of each will vary drastically.
2-Axis CNC Machine
2 axis CNC machines are the most basic CNC systems out there. They contain two axes of movement- the X axis (vertical axis) and the Y axis (horizontal axis). These machines are typically used to create simple straight-line cuts or drill holes on boards.
2 axis CNC machining allows the machining of only a single surface of a workpiece without repositioning it. These machines work on a stationary workpiece.
3-Axis CNC Machine
3 axis CNC machines are the most common types of CNC machines out there. They have 3-axis of movement- the X, Y, and Z axis (depth axis). These machines can machine the most basic parts in 2.5 dimensions.
They can work on all six surfaces of a typically square or rectangular block of material, but the block requires repositioning. These machines also work on a stationary workpiece.
4-Axis CNC Machine
4-axis CNC machines are similar to the 3-axis machines. Besides the three axes-X, Y, and Z, a 4-axis machine also contains an axis of rotation. This axis allows the cutting tool movement in a circular direction along the X-axis, known as the A-axis.
In some cases, instead of the movement of the cutting tool on the A-axis, the workpiece might be moved on the same axis. These machines are useful for making cutouts and cutting along an arc.
5-Axis CNC Machine
5-axis CNC machines add a pivoting motion of the cutting tool (or the work table) along the Y-axis. The axis of rotating pivoting motion is called the C-axis.
These machines operate to create very intricate and accurate parts due to the ability to work on five surfaces of a workpiece at once, without repositioning the work surface.
The high accuracy makes these machines very useful in accuracy required job budget such as medical and aerospace equipment.
6-axis CNC Machine
A 6-axis CNC machine adds the third rotary direction to the cutting tool (or the work table). This third direction is known as the B-axis. These machines can create shapes of any possible surface finish by involving all possible movement directions of the cutting tool and workpiece.
These machines are used in the medical, aerospace, and military industries for all applications (unless internal features are required).
7-Axis CNC Machine
7-axis CNC machines have 3 traditional axes involving the movement of the cutting tool, 3 axes for the rotary movement of the workpiece, and a seventh axis that can rotate the arm holding the cutting tool. This axis is called the E-axis.
These machines are again used in aerospace, medical, and military equipment as the complexity of parts increases.
9-Axis CNC Machine
9-axis CNC machines are a combined CNC setup of a 5-axis milling machine and a 4-axis lathe machine. The milling machine works on the surface to create the required surface finish, while the lathe completes the internal features of the workpiece.
This way, a 9-axis machine can make both internal and external features of the part. These machines are used for dental implants, surgical tools, and complex aerospace equipment.
12-Axis CNC Machine
12-axis CNC machines are the most complex machinery in the industry, and can even be overkill for most applications. These CNC machines contain two cutting heads that move in all 6 possible axes- X, Y, Z, A, B, and C. These machines not only exponentially increase the accuracy, they also lead to speeding up the production to twice the speed or more.
Types of CNC Machines According to the Control System
The basic principle of a CNC machine is to move the cutting tool and the workpiece relative to each other. For this, the cutting tool is constantly repositioned and taken to the required place. There are different ways in which tool repositioning works, leading to three different types of CNC machines:
Point to Point Positioning Control
The Point to Point control system is also abbreviated as the PTP system. It is the most basic type of control system. In this control system, the cutting tool moves to a predefined point after which the machining starts around the predefined point.
PTP is the cheapest of all positioning systems. It is used for operations such as drilling, spot welding, tapping, and reverting; where simultaneous positioning and machining are not required.
Straight Cut Positioning Control
In Straight Cut positioning control, the cutting tool can simultaneously reposition and machine the workpiece. However, the movement occurs only in parallel to one axis at a given time. The movement and machining are both done at a controlled rate. This control system is named so because the machining occurs in a straight line and curved cuts are not possible.
Contouring Path CNC System
The Contouring Path CNC system is also called Continuous Path CNC System. It is the most expensive of all three positioning control systems and can create the most intricate parts. These systems are capable of both- PTP positioning and Straight Cut Positioning. Additionally, they can control the cutting tool positioning in multiple axes simultaneously.
This provides the ability to create curved surfaces (contours) on the workpiece. CNC machines such as milling and turning employ this method for operation.
After reading all the information provided here, it is evident that there are almost countless types of CNC machines. It can be overwhelming to decide which CNC machine would suit your purpose the best. The harder choice comes after you decide on the CNC machine type you require; how to afford the high initial investment of the CNC equipment?
Fortunately, one can use the most advanced CNC machine capabilities without buying the machine itself. This is done by outsourcing the CNC services to industry-leading experts such as 3ERP.
3ERP houses all possible types of CNC machines, from simple 3-axis machines for cheap manufacturing to multi-axis high-tech machines for the most intricate parts. Additionally, the specialized team of engineers can handle any requirement you throw at them.
To know more about how much CNC machining services will cost you, get in touch with the 3ERP team.
Frequently Asked Questions
1. How Many Different Types of CNC machines are there?
There are countless types of CNC machines due to many different subtypes of common types of CNC machine processes such as milling, drilling, laser cutting, EDM cutting, lathe, and more. Every type of process has numerous options of axes and positioning systems, leading to a very wide range of classifications.