The term "CNC 3D printer" can be a bit misleading because traditional CNC uses subtractive methods which involves removing unnecessary parts from a block of material, whereas 3D printing employs additive methods by starting with a blank canvas and using materials to build a product layer by layer. Essentially, CNC machines subtract material, while 3D printers add material.
However, many modern 3D printers utilize control systems that are based on the same principles as those used in Computer Numerical Control (CNC) machining. These systems provide the precise motion control needed for the printer head or bed to move accurately.
Understanding the Core Processes
To understand how a machine controlled by CNC principles works in 3D printing, it's important first to distinguish the two core manufacturing methods:
3D Printing: The Additive Approach
3D printing is an additive manufacturing process. This means it builds an object by adding material, typically layer by layer, until the final product is complete.
- Process: The printer starts with a design file (usually an STL or 3MF file). This file is sliced by software into thin horizontal layers. The printer then reads these instructions and deposits or solidifies material precisely for each layer, building the object upwards.
- Materials: Common materials include plastics (like PLA, ABS), resins, metals, ceramics, and composites.
- Types: Popular types include:
- FDM/FFF (Fused Deposition Modeling/Fused Filament Fabrication): Melts and extrudes plastic filament.
- SLA (Stereolithography): Uses a laser to cure liquid resin.
- DLP (Digital Light Processing): Uses a projector to cure liquid resin.
- SLS (Selective Laser Sintering): Uses a laser to fuse powdered material.
CNC Machining: The Subtractive Approach
CNC machining is a subtractive manufacturing process. As the reference states, CNC uses subtractive methods which involves removing unnecessary parts from a block of material. This is done using tools like mills, routers, or lathes that cut, drill, or shape a solid block (stock material) to create the desired object.
- Process: A design file (often a CAD file) is used to generate toolpaths in CAM (Computer-Aided Manufacturing) software. A CNC machine follows these digital instructions precisely, moving cutting tools along multiple axes (X, Y, Z, and sometimes more) to remove material from the stock.
- Materials: Can work with a wide range of materials, including wood, plastics, metals, foam, and composites.
- Tools: Uses various cutting tools depending on the material and desired shape.
How 3D Printers Use CNC Principles for Control
While the manufacturing process is fundamentally different (additive vs. subtractive), the control systems that guide the movement in many 3D printers are based on CNC technology.
CNC Control Systems in 3D Printing
Modern 3D printers, especially FDM types, rely on precise, digitally controlled motion along multiple axes (typically X, Y, and Z) to accurately place material layer by layer. This motion control is where CNC principles come into play.
- Axis Movement: Just like CNC mills or routers, 3D printers use stepper motors to move the print head (carrying the extruder or laser) along the X and Y axes and to move the build platform (or the print head) along the Z axis. These movements are highly accurate and repeatable.
- G-Code: The instructions for these movements are typically provided in a language called G-code. G-code commands specify coordinates, speeds, and other parameters for the machine's operations. This is the same type of control language used in traditional CNC milling machines.
- Control Board: A control board (like Arduino-based or 32-bit boards) interprets the G-code and translates it into electrical signals that drive the stepper motors, coordinating their movements to execute the precise path required for each layer.
So, while a "CNC 3D printer" isn't a machine that performs both subtractive and additive manufacturing simultaneously in a combined process (though hybrid machines do exist), the way a 3D printer's components move is often managed by control systems developed from CNC technology.
Key Differences Summarized
Based on the fundamental distinction highlighted in the reference, here's a summary of the key differences between the core processes:
Additive vs. Subtractive Manufacturing
| Feature | 3D Printing (Additive) | CNC Machining (Subtractive) |
|---|---|---|
| Process | Builds object by adding material layer by layer | Shapes object by removing material from a block |
| Material Use | Uses roughly the amount of material needed + support | Starts with more material than needed, generating waste |
| Primary Tools | Extruder, laser, projector, powder bed | Mills, drills, routers, lathes |
| Waste | Minimal material waste (mostly support structures) | Significant material waste (chips, dust) |
| Complexity | Excels at complex geometries, internal structures | Excels at high precision, smooth finishes |
In conclusion, a 3D printer operates using an additive process to build objects layer by layer, a fundamental difference from traditional CNC which subtracts material. However, 3D printers leverage precise, digitally controlled motion systems based on CNC principles to guide their additive manufacturing process accurately.
