Micro CNC machining
Do you know how micron-sized robotics gears, tiny slots in biomedical devices, micro-heat sinks, and other miniature items are manufactured so precisely? All of these rely on micro CNC machining techniques. The process is similar to regular machining, but the tooling, work size, and whole setup are scaled down.
The micro CNC machining services are popular in aerospace, semiconductor, electronics, robotics, and many other industrial manufacturing sectors to produce miniature components.
Since tool sizes are small, it requires precise tool paths at the micro-level. It is challenging than conventional machining processes. Let’s discuss the process,
What is meant by Micro CNC Machining?
Micro machining operation
As the name suggests, micro CNC machining is a type of subtractive manufacturing that creates miniature parts & features, typically below 1 mm or microns in size. What makes it different from standard CNC machining is the use of small tools with minimal runout. The size of the tools can be as low as 0.1 mm.
You can make tiny holes, threads, channels, grooves, and other geometrical features with precision micromachining methods like micro milling, turning, drilling, EDM, and Swiss turning. Basically, it is the same process as CNC, but working on a small level.
Furthermore, the micro-machined components can be as precise as ± 0.010 mm, even for the complex part designs. This precision and detailing are crucial in including medical micro machining, semiconductor, aerospace, electronics, and many other industrial sectors.
What Are the CNC Micro Machining Processes?
There are several types of micro CNC machining processes with different capabilities. It includes micro milling, micro drilling, EDM, laser cutting, etc.
The elaboration below further breaks down into these processes.
CNC Micro Milling
The micro milling process makes the tiny profiles, contours, holes, drills, and many more 3D features on the workpiece. The rotating tool, which sizes down to 10 µm with an RPM of more than 10,000, is used in the process. At the same time, the tolerances remain in a range of a few microns.
CNC Micro Drilling
The process of drilling holes less than 3mm is typically known as micro drilling. Sometimes, the hole diameter can be down to 50 µm. Moreover, technologies like ultrasonic and laser also allow drilling holes smaller than this.
It is important to ensure the correct peck/pass strategy and positional alignment between the work and the tool in micro CNC drilling. Some common uses include drilling PCB boards, fuel injector nozzles for engines, and tiny screws holes for electronics.
CNC Micro Turning
Although the typical lowest diameter of parts that can be achieved with micro turning is 10 µm, it can go further down with specialized micro-lathes. Often, Swiss turn machines are used for this, which offer tight tolerances, as low as ±0.005 mm. Moreover, the micro turning can create miniature cylindrical items and various features on them.
Micro EDM
EDM machining uses heat instead of shear force for material removal. The workpiece and tool(electrode) remain inside the dielectric fluid and create discharges (sparks) when current passes through the EDM circuit. You can use this even for hard materials like titanium alloys and tool steels.
This method is widely used to produce dies, molds, semiconductors, and many other applications requiring complex shapes/features having high aspect ratios.
Laser Micro Machining
In this process, a concentrated laser pulse strikes the material for a fraction of a second, nanoseconds to femtoseconds. The intense heat melts the material and shapes the workpiece. The size can be as low as 10 µm. Consequently, it is compatible with non-metallic workpieces, including plastic, ceramics, and composites.
Applications of CNC Micro Machining
micro machined parts
The micro CNC machining is heavily used in the industrial production of miniature components having extremely small features with tight tolerances and fine finishes.
The table below outlines the applications in medical, aerospace, automotive, semiconductor, and other industries.
| Industry | Typical Materials | Examples |
| Medical | Ti-6Al-4V, 316L stainless, cobalt-chrome, PEEK | Hypodermic needles, catheter tips, micro-screws, and implant components |
| Electronics | Copper, beryllium-copper, brass, FR-4, ceramics | PCB micro-vias, connector pins, MEMS housings |
| Aerospace | Titanium alloys, stainless steels, and aluminum alloys | Fuel injector orifices, sensor housings, micro-actuator shafts |
| Watchmaking | Stainless steel, brass, specialized watch alloys | Gear wheels, pivots, escapement components |
| Automotive | Hardened steels, stainless, brass, and aluminum | Injector nozzles, flow restrictors, sensor housings |
| Jewelry | Gold, silver, platinum, brass | Tiny clasps, filigree parts, micro-engravings |
| Research | Polymers, aluminum, stainless, ceramics | Microfluidic chips, sensor test fixtures, prototypes |
| IoT / MEMS | Stainless steel, aluminum, ceramics, and engineering plastics | Sensor housings, micro-nozzles, flow sensor ports |
Industry Practices and Tips for Micro Machining
As the tooling, setting, and workpiece clamping are done on a small scale during micro machining, it is sensitive than regular CNC processing. Precise tool paths, tool wear, material sensitivity, quality control, and burr formations are the key challenges in micro machining operations.
Here are some practical tips based on industry practices to tackle the above challenges:
- Choose the Right Parameters: Set cutting speed, feed rate, cutting depth, and spindle speed, and other variables carefully.
- Thermal Management: Micro-parts machining can also build up the heat, so use a suitable coolant flow in the machining area. You can use water-based or synthetic coolant based on the scenario.
- Tool Selection: Choose an appropriate tool and sizes made from a hard material, coated with TiAN.
- Secure Work Clamping: Ensure secure clamping of the workpiece and its alignment with the cutting tool.
Conclusion
Micro CNC machining is a necessity of modern manufacturing. It produces functional components that are in microns or a few millimeters in size. However, using the right equipment, micro tooling, and machining parameters is essential to achieve the tight precision and leverage the many benefits of this technology.
Need expert consultation before placing an order or starting the production cycles? Industry-leading companies like ProleanMFG can help you with your project.