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Difference Between CNC Machine Axes

difference between machine axes

CNC machines use a variety of different axes. But having more axes on a device is not necessarily better. Understanding the different axis counts used for CNC machining and their applications will make it easier to select the best machine for your purposes.

What Is CNC Machining?

what is cnc machining

CNC, computer numerical control, machining uses a computer program to direct the cutting tools used. Machining has several techniques that may be controlled by a computer program. Screw machining , milling and turning are some of the applications of CNC machining. All have in common a computer control system, which gives them the name of CNC.

Software used to control the CNC is often computer-aided machining or computer-aided manufacturing, CAM. Don't confuse this software that translates the images into language the CNC machine can understand with the CNC machine itself. The two systems rely on each other to properly create the desired design. The CAM gives the instructions to the CNC, but the CNC system tells the machine what to do using the code generated by the CAM from the design.

After programming the part, the machines move the tools along multiple axes to get the precise cuts needed. The ability to automate the process removes some concerns about human error, though it still takes a professional to choose the right tools to use with the machine to get the best finish. Types of end mills, material and axis number are only a handful of the multitude of factors a professional controller must consider when using a CNC machine.

Different Axis Counts for CNC Machining

Axis counts for CNC machines can range from three to five. More does not necessarily make for a better project, though. Choosing the right number of axes to balance cost and finish is an integral part of machining. All machines start with three axes. The three axes model performs essential functions, and in the hands of an experienced machinist, can be used for more advanced creations. Four axes on a CNC machine add an extra cutting direction, which increases precision. The fifth axis further improves the accuracy of the machine, but the cost of the five-axis CNC machine makes it too expensive for most businesses. Additionally, the extra cost is unnecessary for most applications aside from the most intricate parts used in highly specialized industries.

When selecting the type of machining needed, three-axis machining suffices for most. For specific projects, though, you may need a rare use of a four or five-axis CNC machine. Generally, the geometry of the part will help determine how many cutting axes you need. For instance, deeper or more intricate parts require four or five axes in most cases. But even something as delicate as a turbine blade can be produced with three axes with the right operator who knows how to properly index the edge.

Remember, too, that the more axes a CNC machine has, the more preparation time the project will require. Consider this when choosing the number of axes you want to use for your project.

What Is Three-Axis CNC Machining?

Three-axis machining cuts on the x, y and z-axes. Think of the x-axis as "left to right," the y-axis as "forward to backward" and the z-axis as "up and down." These traditional machines have a simpler setup compared to four- and five-axis machines. But three-axis machines also require the operator to have more knowledge in achieving the desired result and how to position or reposition the material.

Unlike other means of crafting parts, three-axis CNC machines only need one workstation to complete the task. By reducing the movement of the part throughout a workshop, the part's creation time drops and precision increases, since a single machine does everything by a carefully controlled computer.

The ideal situation in which to use three-axis CNC machining is when cutting into a shallow piece of material. But there are uses beyond that when in the hands of a well-trained, experienced user. Some standard applications for three-axis machining include milling slots, drilling and creating edges:

  • Milling Slots: Cutting slots into a piece is a common application of a three-axis machine. The slots may be used for furniture pieces that will fit together or to accommodate other parts. Creating interlocking pieces starts with well-cut slots that precisely hold the parts intended for them.
  • Drilling: Drilling holes makes it easier for the future assembly of multiple parts using screws.
  • Cutting Sharp Edges: Edging the material to angle it or cut sharp corners can quickly be done with a three-axis machine.
  • Creating Customized Parts: Experts can use a three-axis machine to develop necessary customized parts for most businesses. The needs of many small companies are readily met by the parts creation achieved on a simple, easy-to-use, three-axis machine.

There will be some situations where three-axis machines may not suffice. Though rare, some cases will require the use of four- or five-axis machines. As these machines are harder to find and cost much more, they should only be used for highly technical work that requires additional axes.

What Is Four-Axis CNC Machining?

Four-axis machines employ another means of cutting by moving the cutter around the vertical axis. The advantage of this additional cutting direction is increased intricacy in the finished product. Because these machines have an extra cutting direction, they cost more to purchase. In many instances, this additional cost gets passed on to the customers of CNC machine operators. Like three-axis machines, the four-axis design has specific uses, but the four-axis style requires more programming at the beginning to get the system setup to create the cuts.

Four-axis CNC machines may cut along all four axes at the same time or along the x, y, and z-axes simultaneously and around the vertical axis separately. These two designs for four-axis machines could affect production time. The more axes cut at once, the faster production goes. This more rapid workflow is one way three-axis CNC machines have an advantage over some four-axis CNC devices.

Due to the creation of five-axis machines, four-axis designs have fallen by the wayside. Additionally, many skilled machinists can create what they need with three-axis devices, which cost less, rather than purchasing the more expensive and complicated four-axis machines. Consider these applications when deciding:

  • Industrial Parts: Complex industrial parts that require intricate details or specific cutting may need the ability to have the machine cut in a fourth direction. These industrial parts often require custom creation because they are proprietary to the companies using them.
  • Prototypes: Many fields require prototype creation before investing in the time and money to create the product on a mass scale. Technology, architecture, industry, and other fields benefit from machined prototypes as a means of seeing a smaller-scale model of the desired product in three dimensions.
  • Art: Artists who work in multiple media may use CNC machining to design their creations. Four- and five-axis machines are easier for nonprofessionals. These machine types require the user to know how to program the machine, but the user needs less skill in positioning the material, as he or she would need to use a three-axis machine to get the same result.
  • Education: Four-axis CNC machines may help educators teach others the basics of using one of these devices without the expense of training on a five-axis unit. Additionally, these machines can make customized teaching supplies and demonstration models that cannot be purchased from a store.
  • Medical Equipment: Medical equipment designs require precision in their execution. That makes four- and five-axis machines some of the most popular options when companies need specialized medical equipment.

What Is Five-Axis CNC Machining?

what is five axis machining

Adding a fifth axis to a four-axis machine further increases the potential applications of the machine. These machines have better precision and require less movement of the original material. Since the material only needs positioning once, lead times get shorter. However, depending on the configuration of the machine, the overall time could be the same or longer than with simpler devices.

Five-axis machines may have one of three common configurations. The "four plus one" style has four axes that run at once, and the fifth has a separate control. "Three plus two" designs have three axes that move simultaneously, while the other two can be controlled separately. True five-axis machines operate all five axes at once. The last model is much more expensive, but it works faster. Compared to three- and four-axis machines, five-axis designs can use shorter tools, which gives these machines their precision.

Thanks to the extra axis of rotation, five-axis machining is used for creating designs that rely on extreme precision. These products are typically used in highly specialized industries where accuracy can mean the difference between life and death. Medicine, military, aerospace, petrochemical, and other fields often use five-axis machining to create their custom parts:

  • Medical Components: Medical parts and tools require a design that's precise enough to ensure the elements used for surgery or replacement parts fit perfectly. Improper cuts or imperfect edges can render medical supplies unusable. This makes five-axis machining the preferred way to create customized medical tools and components.
  • Automotive Design: Modern vehicles are equal parts electronic and mechanical wonders. To ensure the proper fit of mechanical parts , five-axis machines may be used. Additionally, the smaller electrical housings and other parts may require the use of a higher-axis CNC machine.
  • Architectural Components: Architectural designs are essentially giant puzzles where the pieces must perfectly fit with each other. A small error in a cut on one component could put a building's design so far from its original intent that it does not pass inspection. Door frames are one example of architectural pieces that may need five-axis machining to create.
  • Military-Grade Products: The military uses the best of everything to protect the country. And when it comes to vehicles, weapons, and other products, consistency and precision are top requirements .
  • Petrochemical Industry Parts: Oil and gas components for rigs and refineries often have customized designs that need specialized machining to create. Since these parts are unavailable in stores, many petrochemical companies turn to CNC-machined parts for their facilities.
  • Aerospace Components: The precision needed by the aerospace industry for airplanes, rockets, satellites, and more can directly impact human lives. Poorly crafted parts on flying machines could prevent the systems from working together as they should, resulting in manufacturing defects that could contribute to a crash.

While five-axis CNC machines are useful for the above applications, some of them may be achieved using a three-axis machine with the right operator who is skilled in positioning the material and moving it to create cuts on different axes. Opting for a trained expert using a three-axis machine offers several advantages whenever you need custom parts created.

Benefits of Three-Axis CNC Machining

benefits of three axis machining

Despite the numerous applications of four- and five-axis machines, three-axis machining can surpass its cousins in several ways.

The three axes all CNC machines start with are the x, y and z-axes. Three simultaneous cutters reduce the time required to complete a project. By lowering the time requirements for creating custom parts, three-axis machines cut project costs considerably versus using multiple workstations to make a single component.

Three-axis machines have several means of reducing time and increasing efficiency. Settings allow for the cutters to only move through the parts of the material yet to be cut. This design prevents the cutters from going past the material and into the air, which wastes time and reduces efficiency.

Compared to creating components by hand, three-axis machines work faster and are more precise. You can put the design of an entire part into the computer and set it to work without additional input. A single operator can, therefore, generate multiple exact copies of the same part with just one computer interaction. Some more intricate parts may require replacing the material to get cuts along the other axes, which increases the usefulness of a three-axis CNC machine.

An advantage three-axis CNC machines have over machines with more axes is their compact form. Since they take up less room in a workshop, three-axis CNC machines are more space-efficient. Additionally, these systems replace multiple other tools, further reducing the space taken up in a working area. With less room taken by machines, operators have more space to move around, which can enhance their productivity and comfort in their working environment.

Find the Right Axis Type for Your Needs

find the right CNC axis type

You don't have to be alone in your CNC machining projects. At American Micro Industries, we have the computer systems and equipment needed to machine your parts accurately and as quickly as possible. Our machining professionals will do everything we can to fulfill your custom part designs. Contact us at AMI for a quote for all your CNC machining needs. We'll take the pressure off you as we do our best to complete your project to the best of our abilities. Let us know how we can help you by filling out a quote request today.