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CNC, or Computer Numerical Control, is a method where digital instructions control the movement of tools across two to five axes, allowing precise and automated operations. While CNC technology underpins a variety of machines - from 3D printers to laser cutters to even complex vending machines - it is typically referenced in the context of machinery that has a manual counterpart.
CNC technology shines in subtractive manufacturing processes, such as with CNC routers, mills, and plasma cutters, where the goal is to meticulously remove material from a solid block to sculpt an item. Unlike additive manufacturing, which builds objects layer by layer, CNC milling excels in carving out items with exceptional accuracy and repeatability.
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An axis represents a direction of movement. The standard axes in a 3-axis CNC machining are X, Y, and Z. These axes guide the movement of the cutting tool or the workpiece in a three-dimensional space to craft precise and intricate designs.
The X and Y axes typically control the horizontal shifting of the workpiece, enabling it to move left, right, back, and forth at a constant height. Meanwhile, the Z axis is responsible for the vertical travel of the spindle, allowing it to move up and down. This arrangement ensures both stability and precision.
This motor powers the cutting tool on the CNC machine. The spindle rotates the cutting tool within a typical range of 100 to 24000 RPM to remove material and shape the object. It's important to note that the spindle speed limit varies by machine; for instance, the maximum speed on the Tormach is 10000 RPM, while on the Symbiosis it reaches up to 24000 RPM.
The workpiece, also known as stock, is the raw material from which the object is made. It must have flat edges and be securely attached to the CNC bed - a process known as fixturing or workpiece hold-down. Common methods for securing the stock include using a vacuum bed, a fixturing table, or vices.
A rotating unit that holds multiple cutting tools, allows for quick tool changes during machining operations, enhancing efficiency and productivity.
A clamping device mounted on the spindle at the headstock is used to hold and rotate the workpiece securely during machining.
Powers the spindle, providing the necessary torque and speed for cutting operations, essentially determining the lathe's machining capabilities.
Precision-machined rails provide a smooth and accurate path for the movement of the carriage and tailstock along the lathe's axis.
A movable component mounted on the guideways, opposite the headstock, is used to support the end of the workpiece, and can also hold tools for drilling operations.
The controller most commonly takes the form of a computer and it is used to execute functions of the machine. It is the human user interface of the CNC.
The flood coolant pump supplies coolant to the CNC's cutting area, aiding in the effective removal of chips. It also prevents tool breakage due to overheating and stops hot chips from re-welding to the tool. This pump is utilized when milling metals and certain plastics.
Many CNC machines, including all of ours, need compressed air to operate certain functions. The tool changers and mist accessories on our CNC machines, for example, both rely on compressed air.
The coolant mister combines compressed air and coolant to create a misting jet, serving a similar purpose to the coolant pump. The reduced volume of coolant is simpler to maintain clean, and the jet of compressed air effectively blows excess chips away from the tool.
In a CNC machine, the collet chuck - a clamping system - secures the cutting tool to the spindle. The tool slides into the collet or chuck and is clamped down using a collet nut or a chuck's jaws. Our CNC machines feature air-assisted tool holders, enabling the quick and safe exchange of pre-measured tools already set in collets, streamlining the tool change process.
The tool makes direct contact with the stock and removes material to mill out the object. In the next module, we will dive into it for more details.
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Materials that cannot be CNC machined include combustible materials and graphene. Combustible materials can cause a fire, and graphene dust can damage the spindle as it corrodes the equipment and might pose a risk of combustion with certain materials. If you are unsure about which materials can be used in the CNC machines, please make sure to always ask the staff.
