The CNC milling process begins with the creation of a 2D or 3D CAD part design. The complete design is then exported to a CNC-compatible file format and converted by CAM software into a CNC machine program that instructs the movements of the machine and the movement of the tool across the workpiece. Before operators run a CNC program, they prepare a CNC mill by securing the workpiece to the machine's work surface (i.e., table) or workpiece fixture (such as a vise), and mounting the milling tool to the machine spindle. The CNC milling process employs horizontal or vertical CNC powerful milling machines - depending on the specifications and requirements of the milling application - and rotating multi-point (i.e., multi-tooth) cutting tools such as milling cutters and drills. When the machine is ready, the operator initiates the program through the machine interface, prompting the machine to perform the milling operation. CNC milling The creation of these aforementioned features requires a variety of different milling operations:
|Size||Metric units||Imperial units|
|Max. part size for soft metals  & plastics||
2000 x 1500 x 200 mm
1500 x 800 x 500 mm
78.7 x 59.0 x 7.8 in
59.0 x 31.4 x 27.5 in
|Max. part for hard metals ||1200 x 800 x 500 mm||47.2 x 31.4 x 19.6 in|
|Min. feature size||Ø 0.50 mm||Ø 0.019 in|
|Aluminum||Stainless steel||Mild, Alloy, Tool & Spring steel||Other metal|
|6061||304||Mild steel 1018||Brass C360|
|7075||316/316L||Mild steel 1045||Copper|
|5052||303||Mild steel A36||Titanium Gr5 (TC4)|
|2A12||430||Alloy steel 4140|
|201||Alloy steel 4340|
|Alloy steel 1215|
|Tool steel D2|
|Tool steel A2|
|Tool steel D1|
|Tool steel A3|
|Tool steel S7|
|Tool steel H13|
|ABS Flame Retardant||PEEK|
|Limits for nominal size||Plastics (Coarse class (c))||Metals (Medium class (m))|
|0.5mm* to 3mm||±0.2mm||±0.1mm|
|3mm to 6mm||±0.3mm||±0.1mm|
|6mm to 30mm||±0.5mm||±0.2mm|
|30mm to 120mm||±0.8mm||±0.3mm|
|120mm to 400mm||±1.2mm||±0.5mm|
|400mm to 1000mm||±2mm||±0.8mm|
|1000mm to 2000mm||±3mm||±1.2mm|
|2000mm to 4000mm||±4mm||±2mm|
CNC machining is a modern manufacturing technique that utilizes programmable software and computer-controlled equipment to create complex parts and products from a wide range of materials such as metal, plastics, and wood.
With CNC (Computer Numerical Control) technology, the manufacturing process is highly automated and precise. The process begins with a CAD (Computer-Aided Design) file, which is converted into a set of instructions in the form of G-code. This code is then sent to a CNC machine, which follows step-by-step instructions to produce the desired part or product.
CNC machining has revolutionized the manufacturing industry by increasing productivity, improving accuracy, reducing waste, and allowing for complex shapes and designs to be produced with high precision. It is used in a variety of industries, including aerospace, automotive, electronics, and medical devices.
The benefits of using CNC machines are:
1. Enhanced precision: CNC machines can produce highly precise and accurate parts with tolerances as low as 0.0002 inches, which is not possible manually.
2. Increased speed: CNC machines are automated and can run 24/7, thereby offering faster production time for large volumes of parts.
3. Consistency: Unlike manual production, CNC machines produce parts that are identical in terms of size, shape, and quality consistently.
4. Reduced labor costs: CNC machines require less manual labor and supervision, which saves labor costs and improves overall efficiency.
5. Flexibility: CNC machines can be reprogrammed easily to create different parts without the need for complex tool changes.
6. Ability to work with a wide range of materials: CNC machines can work with a variety of materials, including metals, plastics, wood, and composites.
7. Improved safety: CNC machines can run automatically, which reduces the risk of injury for workers and provides a safer work environment.
8. Reduced waste: The precision offered by CNC machines reduces the material waste and scraps generated during the production process.
CNC machines can work with a wide range of materials including metals, plastics, wood, composites, ceramics and more. The types of materials that CNC machines can work with depend on the specific capabilities of the machine, the tooling options available, and the type of work being performed. Here are some examples of materials that can be used with CNC machines:
1. Metals: CNC machines can work with a variety of metals, including steel, aluminum, brass, titanium, copper, and more.
2. Plastics: CNC machines can work with various types of plastics such as polycarbonate, acrylic, nylon, ABS, PVC, and more.
3. Wood: CNC machines also perform operations on hardwood, softwood, plywood, and MDF board.
4. Composites: CNC machines can work with glass and carbon fiber composites, Kevlar, and other composite materials.
5. Ceramics: Machinable ceramics can also be used with CNC machines like porcelain, alumina, zirconia and other materials.
It's important to note that different CNC machines will have specific requirements for the materials that can be used. The feed rate, chip load, and spindle speed will vary depending on the material, so it's essential to understand the material properties and choose the appropriate tools and settings for each job.
CNC turning and CNC milling are both processes used in CNC machining, but there are some significant differences between the two.
1. Operation: In CNC turning, a stationary cutting tool is used to remove material from a rotating workpiece, whereas in CNC milling, the cutting tools rotate and move across the stationary workpiece.
2. Geometry: CNC turning is more suitable for creating cylindrical shapes such as bolts, nuts, pipes, and shafts. CNC milling is better suited for more complex geometries such as pockets, slots, and complex shapes.
3. Tooling: Turning tools are generally simpler and more robust, while milling tools are more complex and can have more cutting edges.
4. Materials: CNC turning machines are mostly used for turning materials such as round bars, billets, and blocks, while CNC milling machines are used for a wide range of materials such as metals, plastics, wood, and composites.
5. Speed: In general, CNC turning is faster than CNC milling, as the tools are shorter and the process is simpler.
6. Cost: CNC turning is usually less expensive than CNC milling, as the tools are simpler and less expensive.
In summary, CNC turning is best suited for creating simple cylindrical shapes, while CNC milling is better suited for creating more complex geometries. Both processes have their advantages, and the choice between them will depend on the specific requirements of each job.
The maximum size of parts that can be machined with CNC machines depends on the size and capacity of the machine being used. CNC machines come in various sizes, and they have different work envelopes that dictate the maximum size of parts they can handle.
Small CNC machines are ideal for small and intricate parts, while larger machines are used for bigger parts. Generally, the maximum size of parts that can be machined on a CNC machine ranges from a few centimeters to several meters.
For example, a small benchtop CNC milling machine may have a work envelope of around 300mm x 300mm x 200mm, while a larger vertical machining center may have a work envelope of 2000mm x 1000mm x 1000mm. In comparison, large gantry-style CNC machines used in the aerospace industry have a work envelope of over 30 meters in length.
It's essential to consider the size and weight of the parts being machined and the capabilities of the CNC machine when selecting a machine for a specific job.