Assuming you want to drill holes in metals, make cylindrical parts, or groove gears, you’ll definitely adopt a process that is accurate and efficient.
With the knowledge on different types of CNC machining processes, you can effectively match your part requirements and fabrication techniques.
Let’s look at some practical options for your CNC machining needs.
What is CNC Machining?
CNC machining is a fabrication process where the machine uses program (G-codes and M-codes) to control either the tooling, workpiece or both. It is an automated process known for its high accuracy, reliability, and reproducibility.
Common Types of CNC Machining Processes
1. CNC Milling
In CNC milling, a tooling system moving in different axes removes particles on a fixed workpiece. Usually, these tooling systems cut workpiece while in rotary motion. It creates flat surfaces, slots, pockets, and 3-D contours.
How it Works
CNC milling machines use three major linear axes (X, Y, and Z). The cutting tool is attached to the spindle that rotates at 500-15,000 RPM, depending on the hardness of the material and the type of tool. Axial movements enable the cutter to cut away the material layer by layer. Contemporary 4-axis and 5-axis systems offer extra rotational axes (A and B), enabling machining of complex shapes, undercuts, and curved geometry.
Cutting parameters are feed rate (mm/min), depth of cut (mm), and spindle speed (RPM). In addition, coolant is used to dissipate heat, minimize tool wear, and ensure dimensional tolerances of +-0.01 mm.
Common Uses/Examples of Parts
- Turbine blades and brackets in aerospace industry
- Automotive engine housings and transmission cases
- Precision medical implants and surgical instruments
- Injection molds and die cavities
2. CNC Turning
In CNC turning, a fixed tooling system automatically cuts a workpiece that is set to rotate in a specific direction and speed. It makes cylindrical components that have smooth finishes and precise diameter.
How it Works
For most CNC operation, the workpiece in the chuck rotates between 500 to 3,000 rpm. The cutting tool travels in straight line along X and Z axes. The X-axis controls depth of cut, while the Z-axis defines length. Multi-axis lathes have C-axis rotation used in spindle indexing and Y-axis movement used in off-center milling or drilling.
Common Uses/Examples of Parts
- Shafts, pins, and bushings
- Hydraulic and pneumatic fittings
- Automotive pistons and nozzles
3. CNC Drilling
CNC drilling is a fabrication technique where the machine makes accurate holes with specified diameters and depth. During drilling process, the machine uses specific drill bits.
How it Works
The drill bit spins as it moves along the Z-axis into the workpiece. Simultaneously, X and Y axes position the drill at the correct coordinates. CNC drilling machines can also have multi-spindle heads where multiple holes can be drilled at the same time.
The cutting speeds depend on the material, in most cases 30-90 m/min with steel and 100-200 m/min with aluminum. Feed rates are managed in mm/rev, guaranteeing straightness of holes and preventing tool breakage.
Common Uses/Examples of Parts
- Printed circuit boards (PCBs) with dense hole arrays
- Aircraft fuselage panels with uniform rivet holes
- Automotive engine blocks and cylinder heads
4. CNC Routing
CNC routing cuts and shapes soft materials such as wood, plastic and composites with high-speed rotary tools.
How it Works
Routers operate with X, Y and Z-axis movements to cut sheet materials. The spindle speed exceeds that of milling, usually 20,000-30,000 RPM, in order to provide clean cuts in the softer substrates. Other machines have rotary axes to 3D carve and contour.
Common Uses/Examples of Parts
- Wooden cabinetry and furniture panels
- Decorative and commercial signage
- Plastic and composite aerospace panels
- Automotive dashboards and interior trim
5. CNC Grinding
With CNC grinding, abrasive wheels are used to cut away small portions of material to provide fine finishes and tight tolerances.
How it Works
The grinding wheel rotates at 20,000-30,000 surface feet per minute (SFM) and the workpiece is moved in X, Y, and Z directions. Precision control provides material removal rates to 0.002 mm per pass. More sophisticated grinding machines include rotary B and C axes, which allow the profiling and contour grinding.
Common Uses/Examples of Parts
- Precision gears and bearing races
- Aerospace turbine blades with tight tolerances
6. CNC Electrical Discharge Machining (EDM)
CNC EDM is a manufacturing process that involves controlled electrical discharges (sparks) to erode conductive material with great precision.
How it Works
There are two major types, namely, wire EDM and die-sinking EDM. In wire EDM, a thin wire of brass (0.1-0.3 mm diameter) serves as an electrode. The wire travels along X and Y axes, cutting profiles and the Z-axis modifies depth. In die-sinking EDM, cavities are formed by a shaped electrode.
Electric discharges under controlled conditions in a dielectric liquid produce heat that melts and vaporizes material, removing it in layers. EDM has tolerances of +-0.002 mm, and can cut intricate geometries that would not be possible by conventional cutting. The cutting speeds are slower, usually 2-10 mm2/min, but unsurpassed in accuracy.
Common Uses/Examples of Parts
- Injection molds and extrusion dies
- Aerospace fuel system components
- Medical instruments with fine cavities
7. CNC Laser Cutting
Laser cutting or laser engraving play a fundamental role in today’s machining industry. Unlike other CNC machining, these CNC machines use focused laser beam to cut parts.
How it Works
The laser head travels on the X and Y axes over the sheet material, with the Z-axis controlling focus height. Beam intensity can reach 10,000 watts and can cut steel as thick as 25 mm. Multi-axis machines include rotational axes, which can be used to make bevel cuts and 3D profile.
The cutting speeds depend on the material, such as 10-20 m/min with thin steel, and up to 60 m/min with plastics. Assist gases such as oxygen or nitrogen improve the quality of cutting. CNC laser systems have tolerances of +-0.05 mm and heat-affected areas are minimal.
Common Uses/Examples of Parts
- Sheet metal enclosures and brackets
- Decorative panels and intricate signage
- Electronic casings and small precision parts
- Lightweight automotive body components
8. CNC Waterjet Cutting
Here, a CNC program control nozzle with high-pressure water to cut through parts. In most cases, this highly pressurized water may have abrasive particles.
How it Works
A nozzle directs water with pressure up to 60,000 PSI, moving along X and Y axes, with the standoff distance being controlled by the Z-axis. In case you want to cut thick metals with up to 200 mm, you can choose waterjet with abrasive materials.
Depending on the thickness, cutting speeds vary between 100 and 500 mm/min. Since there is no heat produced, parts are not subjected to warping or metallurgical changes.
Common Uses/Examples of Parts
- Aerospace composites and layered materials
- Architectural stone, marble, and tile panels
- Automotive gaskets and seals
- Custom metal components with no heat distortion
9. CNC Plasma Cutting
CNC plasma cutting refers to a jet of ionized gas utilized to cut conductive metals.
How it Works
A plasma torch generates a temperature of more than 20,000 degrees Celsius, melting the metal surface. The torch travels on X and Y axes, with the Z -axis changing arc length to achieve quality. High-tech plasma systems have rotary pipe cutting axes.
For thin steel plates, cutting speeds are 1,500-2,000 mm/min. Plasma cutters can cut up to 50 mm thick with tolerances of +-0.2 mm. Torch height control provides a uniform arc quality when cutting uneven surfaces.
Common Uses/Examples of Parts
- Shipbuilding structural steel plates
- Heavy equipment frames and supports
Conclusion
CNC machining operations provide you with unparalleled control over speed, precision and complexity. With knowledge of each type of CNC machining process, you are able to choose the right fabrication process for your production requirements.
If you are looking for a trusted CNC machine supplier in China, DSR is your trusted partner – request for quote.
