Machine Types and Axes
As I mentioned before, there are different types of CNC machine tools on the market. Some are basic, others are advanced. Basic CNC machine tools have three axes. They can perform three-dimensional cutting of workpieces. Five-axis CNC machine tools are more advanced, capable of removing material from five directions.
Three-axis machine tools are inexpensive and ideal for manufacturing parts with simple shapes. CNC machining using three-axis machine tools is generally affordable. On the other hand, five-axis CNC machine tools are more advanced. They utilize modern software and programming techniques. They can easily manufacture parts with complex shapes. Keep in mind that five-axis CNC machining is more expensive than three-axis machining.
Cycle Time, Setup, and CAM Programming
Cycle time and software settings affect the cost of CNC-based machining. Cycle time refers to the time required for the machine to cut and manufacture parts. A longer cycle time means a longer machine uptime. Longer machine uptime increases machining costs, and vice versa.
Setting up CNC machining is not simple. The operator needs to sort the material, place it on the worktable, and secure it to the fixtures. Furthermore, designing CAD files for parts of a specific shape is time-consuming. These initial setups fall under non-periodic engineering (NRE). This means that such setup costs are always present and unavoidable.
However, for prototyping, these setup costs increase project costs. For mass production, you don't need to repeat this setup. Once the CAD design is complete, it will be used and reused throughout the production process. You don't need to redesign it repeatedly. Therefore, mass production costs are generally lower than prototyping.
Part Geometry and Complexity
The geometry of a part also affects the cost of CNC machining. Imagine you want to make a part with a simple geometry. It doesn't have ample space or tight bends. Such parts are easily manufactured through simple three-axis CNC machining. Moreover, machines can manufacture these parts at high speed and high precision. However, some parts have more complex geometries and dimensions.
They are more challenging to manufacture. These parts require high-end five-axis CNC machine tools. Their deep pockets and tight corners require attention and take more time. Therefore, the CNC machine tool run time is longer. The longer the machine run time, the more you pay, because machining costs are generally higher per hour.
Tools and Materials
CNC machine tools are powerful, but they still require tools. These include cutters, drills, and inserters, and the list goes on. These tools are expensive and increase machining costs. Furthermore, some materials are harder. More robust tools are needed for manufacturing them, further increasing costs.
