March 21, 2022

3 axis vs 5 axis CNC

What is the 3-axis?

Machines with three axes frequently produce 2D and 2.5D geometry. In 3 axis machining, you can machine all six sides of a product, but each requires a different fixturing setup, which can be costly. Only one side of the part can be machined using a single fixture arrangement.

Three-axis CNC milling can produce a wide range of sophisticated and functional shapes, primarily used by a world-class CNC machining facility. Planar milled profiles, drillings, and threaded holes in-line with an axis come from 3-axis machining. You can use T-slot cutters and Dovetail milling cutters to create undercut features.

However, in some cases, a 3-axis machine cannot physically create the planned feature, or the part may be more financially viable to process with a 4 or 5 axis machine. Any components at an angle to the X-Y-Z coordinate system, even if the feature itself is planar, are not conceivable in 3 axis milling.

What is the 5-axis?

These CNC milling machines use two of the three potential rotation axes depending on the machine. The A-axis and C-axis will rotate, or the B-axis and C-axis will rotate. 3+2 machines and completely continuous 5-axis machines are the two primary types of 5-axis CNC machines. The workpiece or the spindle is the source of rotation.

Two rotating axes function independently in 3+2 axis machining, allowing you to turn the workpiece to any compound angle about the cutting tool for machining features.

Fully continuous 5-axis machining allows the two rotating axes to spin simultaneously while machining and the cutting tool moves linearly in XYZ coordinates. However, machining with two axes at the same time is not possible. 3+2 machining is capable of producing highly complicated 3D objects.

Continuous 5-axis machining can create highly complicated 3D structures, including complex curved 3D surfaces and planar compound angled features, allowing us to build parts traditionally reserved for molding methods. 5-axis machining will enable designers to create highly complicated 3D geometry with a great deal of freedom.

Difference between 3-Axis Machining and 5-Axis Machining?.

The critical distinction between 3-axis and 5-axis milling machines is that the former can work on the workpiece from three axes while the latter can work from five. Both are highly versatile, automated, and repeatable production techniques that allow you to rapidly and cost-effectively generate correct components. For various reasons, you may like to use one over the other.

3-axis machines are a good option if you’re on a tight budget or only need to cut a flat surface. In addition to being less expensive than machines with five axes, 3-axis machines are easier to program, which means you won’t have to pay for expensive specialist programmers and operators. In addition, 3-axis machining reduces prep time.

You’ll probably want to employ 5-axis machining if you need to make a deeper part or one with intricate geometry. Using 5-axis machines, you can mill the workpiece from all sides, eliminating the need for manual rotation. You’ll get higher yields, improved accuracy, and more freedom of movement with 5-axis machining, as well as the capacity to make more significant components faster.

Advantages of the 3-axis

  • A machining centre with three axes can mill a component by simultaneously moving the axes in three separate directions.
  • Another benefit of 3 axis machining is that all three axes move simultaneously. Compared to 2.5 axis machining, this allows the machine to make more complicated components.
  • Three-axis machines can produce a whole machining element. Fixtures, clamps, stocks, and machine clamps are examples of these.
  • You can integrate an automatic tool changer with the machine. And this allows the device to perform various tasks with just one machine.
  • The machine must enter the milling instructions into the computer. The device then performs the task automatically after this is complete.
  • Once you enter the instructions, the machine may make several copies of the same product, all to precise dimensions.
  • You can customise Three-axis CNC machining centres to meet a client’s needs. 
  • You can also modify machining centres with four or five axes.

Disadvantages of the three-axis?

You can only cut in three directions with 3-axis CNC machines; they may face a challenge with distinctive shapes or designs with deep, narrow cavities that are hard to reach. 

Operators may have to manually correct the workpiece when operating parts with complex geometries, which can slow down processing speed, increase labor and machining costs, and result in a less-than-perfect completed product.

Advantages of 5 axes?

  • Single Setup: You require multiple setups for 3-axis machines, leading to inaccurate alignments, higher costs, and other issues. You can create complex forms with a single design with 5-axis machining, which increases efficiency, saves time, lowers costs, and eliminates operator mistakes.
  • Shorter Cutting Tools: You can use shorter cutting tools to reduce the head and orient the cutter suitably with 5-axis machining. And this allows for faster cutting without placing too much strain on the cutter.
  • Complex Pieces: This method enables you to manufacture complex parts that would otherwise be unnecessary. You’ll be able to machine your components in a few weeks instead of waiting months for casting to be completed if you have small batches or prototypes.
  • Increased Tool Life: By maintaining a steady chip load and optimal cutting position, you can save cycle time and increase tool life.
  • Hole Drilling: 5-axis machining allows you to drill a sequence of holes with different compound angles in a short amount of time. And this saves a lot of time since if you utilised a 3-axis machine, each spot would require a typical setup.
  • Collision Avoidance: The capacity to tilt the table or cutting tool to avoid colliding with the tool’s holder.

Disadvantages of 5-axis?

  • The Price Is Too High — On the one hand, the price of a five-axis machine tool, as well as the software necessary, is significantly greater than the price of a standard three-axis machining centre. On the other hand, the machine’s upkeep is more complicated than typical machinery. These factors also contribute to the fact that 5-axis machining parts are substantially more expensive than 3-axis machining.
  • Difficult To Program — 5-axis machining differs from 3-axis machining in that it involves two rotational motions in addition to three linear movements. The composite motion’s resulting spatial trajectory is highly complicated and abstract, making it difficult to visualise and comprehend. Programming is significantly more challenging to achieve machining accuracy and surface quality.
  • Operators must meet stringent technical requirements – Five-axis machining is a more advanced machining technique, and it necessitates the use of higher-level skills. It differs from traditional three-axis machine tools in every way, from simple programming to machining operations. As a result, highly trained operators are necessary, resulting in more significant labour expenses.

Compare the use of 3-axis and 5-axis 

3-Axis machining is a pretty simple procedure taught to university students as part of their Level 3 Engineering degrees, but it has remained a convenient milling solution for decades. 3-axis production is now easier than ever, thanks to CAD/CAM technology. 5-axis machining, contrary to popular belief, is not as challenging to set up as it appears.

While the inclusion of two axes necessitates extra levels of programming, this only makes the process more detailed, not generally more complex. It takes longer to prepare, but it entails less material handling and less danger of adding imprecision due to human error. 

When cutting a component on a 3-axis system, frequent stoppages and human adjustments of the workpiece are almost inevitable. With 5-axis machines, this isn’t necessary, enabling the device to run without human intervention.

Compare the costs of the 3-axis and 5-axis.

The cost is why many manufacturers are unwilling to switch to 5-axis machining. Because of the extra complexity and technology involved, 5-axis machines are initially more expensive than 3-axis machines. 

While this may be a disadvantage, a 5-axis machine will save money in the long run by reducing waste materials, cycle times, and the need for servicing due to the shorter cutting tools that allow for faster cutting rates. 5-axis machining will save you a lot of time and enable you to make more components in less time for features requiring more complexity.

Overall comparison for 3-axis and 5-axis

In the end, both 5-axis and 3-axis machining have their advantages and disadvantages. While 5-axis machining provides better capabilities and efficiency across the board, some components may not require the additional two axes. In 3+2 machining, for example, the extra two axes are utilized to locate the workpiece or cutting tool rather than milling it directly. And this means that all five axes do not have to move simultaneously.

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