Using CNC machining is becoming a vital production technique. Medical, aerospace, optical, mechanical, and other sectors use CNC precision machining for milling. Milling removes material from a workpiece by inserting it at an angle to the tool axis using rotary cutters. A milling machine’s axes define its capabilities and workpiece positions. CNC milling works well for angles, slots, holes, curves, flat surfaces, and channels.
When you choose this milling, you must know which will suit your project. Since Three-, four-, and five-axis milling might initially seem confusing. So, here we provide you with this guide to explain the differences and which is best for you.
What is CNC Machining?
Computer Numerical Control’s short form is CNC. It is a stock piece of material from which a custom-designed object is created using computer-controlled and machine-tooled subtractive manufacturing. You can use this technology in large CNC machining, parts machining for telecommunications, and CNC machining aerospace.
CNC machining and CNC machine are different. The technique of CNC machining is distinct from the machine itself. The processes of computer numerical control (CNC) machining processes may be performed automatically by a machine known as a CNC machine.
Our topic concerns 3 Axis, 4 Axis & 5 Axis of CNC machining. But what does that mean? Does it similar to that axis that we read about in our school? Axis is used to represent motion along a specified route. Remember, whenever you do a graph in mathematics, you may draw an x-axis and a y-axis. For example, you can use a chart to figure out how much you spend money on breakfast. Then time moves with the x-axis, and breakfast moves with the y-axis.
The same principle is used on a CNC machine. Computer numerical control (CNC) machines use CAM/CAD software that guides the cutting tools as they form a component. The CNC mill moves from left to right as it works.
That direction is the x-axis of that machining. According to the rule of motion, the leftward movement goes in the negative direction, whereas the rightward movement is in the positive order.
What is Multi-Axis Machining?
CNC machining with the ability to rotate and move the cutting tool in three or more axes is known as multi-axis machining. As the number of axes increases, the difficulty of multi-axis machining rises accordingly. More complex machinery and software are required for CNC machines with multiple axes.
Types of Common Multi-Axis Machining
You may get CNC machines with three to twelve separate axes in various planes. The most common configurations for multi-axis machines are outlined here.
The most basic multi-axis CNC machining involves just three axes. The workpiece remains in one place as the spindle rotates in three dimensions (X, Y, and Z).
These CNC mills have one linear axis and two rotary axes that control separately. The cutting tool rotates around all three axes connected by an electronic or mechanical linkage.
The X-axis runs in a direction that is parallel to the cutting tool. It enables the milling head to move along and across the dimension of the object. The Y-axis always stays in a position that is perpendicular to the cutting tool. So the milling head can reach both ends of the piece. While the Z-feed shifts its place, the Z-axis will be vertical to the cutting tool. By doing this cutting tool will be allowed to slice along the object’s surface.
Where can you use 3-axis machining? Most often used to manufacture mechanical components, three-axis machining is best suited for:
- Automatic/interactive operation
- Slot milling
- Cut Sharp Edges
Similarly, 3-axis CNC milling uses a cutting tool to eliminate the substance from an object to form a specific shape or profile. The same applies to 4-axis CNC milling, but it has a different rotating motion around the X-axis, referred to as the A-axis.
Accuracy in 4-axis machines is higher because of the fourth axis’s motions. It enables rotations around the vertical axis, providing machines with 360 degrees of dynamic movement without requiring specialized mounting.
When making holes and cutouts in the side of a component or around a cylinder is necessary, 4-axis milling is an effective method. They can do fast, accurate work depending on the numerical inputs of computers.
Because of its additional axis, the 4-axis mill is a more cost-effective alternative to the 3-axis CNC mill. In addition, since it can process all four sides of the workpiece simultaneously without needing to relocate it, 4-axis milling provides a higher overall quality product than 3-axis milling. Because of this, potential instances of human mistakes are eliminated.
As the machine can rotate the object on its own due to the inclusion of a fourth axis, it may perform subtractive operations on both sides simultaneously. Because of its adaptability, four-axis machining may be utilized for various purposes, including
- Intermittent cutting,
- Continuous cutting,
- Carved surface
Five-axis numerically controlled (CNC) machine tools allow for fully automated motion along the X, Y, and Z axes and the selection of two of the three rotating axes (A, B, C). It has also known as 3 + 2 machining.
The A, B, and C axes each rotate 180 degrees with regard to the X, Y, and Z axes. The automobile, aerospace, and marine sectors all use this form of machining. It is also ideal for fixtures, housing, and other components often used in manufacturing that do not need high shape control. This method works well for casting exceedingly complex solid components. 5-axis machining requires more CNC programming preparation. It needs time to adapt to complicated rotating movements to cut all five sides of an element in one action.
Moreover, the B-axis allows for unparalleled accuracy, polish, and speed in the manufacturing process because of its ability to rotate and move tools in several dimensions.
It can produce complicated and accurate components for:
- Artificial limbs,
- Aircraft equipment,
- Titanium components,
- Oil and gas machinery,
- Automobile molds,
- Medical equipment,
- Construction tools, and
- Military hardware.
So 5-axis machining might be the most excellent option for creating a highly functional design.
What Is the Difference Between 3, 4, and 5-Axis CNC Machining?
1. Number & Movement of the Axis
The number and movement of the axis is the most significant difference between the three. A 3-axis CNC machine can move in vertical and horizontal planes and side to side. A CNC router with just four axes will only have one rotating axis, whereas a CNC machine with five axes would have two rotational axes.
Using CNC in manufacturing ensures high accuracy while reducing possible errors. However, you can get a high level of accuracy by using 3-axis CNC machining. But there is still a possibility that mistakes might occur due to the constant repositioning of the object. On the other hand, this margin of error is not critical for the majority of applications. However, the slightest variance might cause problems for delicate aircraft applications.
Meanwhile, 4- and 5-axis machines can be repositioned. Thus, they often don’t have the same distortion problems as 3-axis machining. 4- and 5-axis CNC machines have the capability of adding features to a workpiece in a variety of different planes and locations with only one fixture.
A 4-axis CNC machine’s rotary axis increases flexibility and makes it worthwhile in several contexts.
On the other hand, a 5-axis machine’s increased rotating speed and additional rotational axis provide even more customization options.
4. Working Principle
Every kind of CNC machining adheres to the same fundamental mode of operation. Computer numerical control machinery uses a rotating cutting tool to carve out the necessary shapes from a workpiece precisely. Moreover, the movement of the cutting tool in CNC machines may be commanded by G-Codes or M-Codes. The capacity to spin around multiple planes distinguishes 3-, 4-, and 5-axis devices.
3-axis, 4-axis, and 5-axis machining costs are also significant differentiators among the methods mentioned. The 3-axis machine is the most cost-effective alternative in the long run. Yet, machine operators and fixtures impact the cost of running 3-axis machines in a workplace. On the other hand, four- and five-axis machines are more complex and costly due to their increased capabilities.
3-Axis vs. 4-Axis vs. 5-Axis Machining: Comparison Table
Let’s look over the differences between the 3, 4 & 5-axis of machining:
|3-axis has x, y, z axis||4-axis has x, y, z, and b axis||5-axis has x, y, z, w, and b or x, y, z, a, b|
|3-axis is slower than 4 & 5-axis.||4-axis is faster than 3-axis but slower than 5-axis.||5-axis is the most rapid multi-axis machining.|
|The direction of the cutting tool does not change at any point. Throughout the cutting path.||The 4-axis includes a rotation axis to the three axes, typically representing a rotation of 360 degrees in the horizontal plane.||The linear motion of the tool is performed simultaneously, and its direction is optimized. |
It passes throughout the whole route.
|The 3-axis equipment is inexpensive.||The 4-axis is pricier than the 3-axis.||The cost of 5-axis machinery is higher than that of 3 and 4-axis machines.|
Which CNC Machine Is Best for You?
Even though 5-axis CNC machining has several benefits over 3- and 4-axis systems, not all items can be machined. Likewise, not all goods machined with 3-axis CNC systems can be machined with 5-axis CNC systems. This section will help you determine which approach is best for your work.
- Three-axis milling is the best option for producing primary, high-volume products. 3-axis CNC milling is used to grind surface structures, cut keyholes, and drill shallow holes.
- 4-axis CNC machining is ideal for items that need drilling holes in the side of a component or the surface of a cylinder. It has good processing accuracy and can handle data quickly.
- 5-axisCNC milling is an excellent option for complicated items that must be manufactured quickly and precisely due to its high flexibility and speed.
Why Is 5-Axis Milling Beneficial?
A 5-axis milling machine offers more design flexibility than 3 & 4- axis milling. It can move in any direction freely. Moreover, it has three cutting tools, including one vertical and two horizontal spindles. So with the help of this milling, using both right angles on a single piece of the material allows for far more precise cutting of complex shapes.
How Can You Define a 5-Axis CNC Machining Center?
The head of a five-axis machine may spin in five separate directions to have various rotational and linear motions. A CNC 5-axis machining center’s accuracy and speed make it ideal for quickly producing multiple shapes.
Machines with more than three movable axes are often bulkier and heavier than their 3-axis equivalents to accommodate the extra motion. Most 5-axis machines employ rotational rather than linear motion to manufacture, so they are classified as horizontal boring mills.
What Are the Limitations of the 3-Axis Machining Process?
The limitations are:
- Less specific qualities
- Limited capability for complex machining
- Due to restricted tooling access, machined surfaces have less complexity
- Have no freedom of movement
What Are the Limitations of the 4-Axis Machining Process?
The Geneva Mechanism is the main drawback of the 4-axis milling machine. It is widely used because of its simplicity, dependability, and accuracy. Yet, it only permits the fourth axis in theory. But, in practice, continuous machining is impossible with these machines due to their predetermined limits. Thus, operators can only use the equipment in an indexing capacity.
What Are the Limitations of the 5-Axis Machining Process?
The 5-axis CNC machine has certain drawbacks, even though it is an excellent tool for rapidity and accuracy.
- When visualizing the spatial trajectory, the CAD/CAM programming for 5-axis machines may get quite complex.
- As 5-axis milling machines are rare, buying and maintaining one and its equipment is costly.
- A 5-axis machine demands a highly trained CNC machine operator.
The 3-axis is the most fundamental kind of CNC machine. It has spindles that can only move vertically, horizontally, and side-to-side. In contrast, machines with four axes are more effective and versatile because of the addition of a fourth, rotating axis. The most precise, economical, and flexible machining is provided by 5-axis CNC machines, which add a second rotating axis. So we hope you have completely understood the differences between low-fidelity and high-fidelity prototypes and can choose the best one that suits your requirement.