How Precise Can CNC Machines Be?

Accuracy of different types of CNC machine .

The precision of CNC machine tools varies due to different types. The machining accuracy of ordinary CNC machine tools has been improved from 10 μ m to 5 μ m, while that of precision machining centers has been increased from 3-5 μ m to 1-1.5 μ m. Ultra precision has begun to enter the nanometer level (0.01 μ m).

Numerical control lathe: Generally, better lathes can process products with a maximum tolerance zone of 6 levels. The machining accuracy of numerical control machine tools can usually reach 0.05-0.1mm. However, when controlled in digital signal form, for each pulse signal output by the numerical control device, the moving parts of the machine tool move by one pulse equivalent (usually 0.001mm), and the reverse clearance of the machine tool feed transmission chain and the average error of the screw pitch can be compensated by the numerical control device, so the positioning accuracy is relatively high.

CNC milling machine: Some CNC milling machines have a positioning accuracy of 0.008mm and a repeated positioning accuracy of 0.003mm, achieving precision level; Some have a positioning accuracy of 0.008mm and a repeat positioning accuracy of 0.005mm, both belonging to high-precision machining centers.

High speed CNC machine tools: The machining accuracy of high-speed CNC machines can usually reach the level of a few micrometers, but not less than 0.01 millimeters. Higher accuracy depends on the coordination of factors such as machine tools, cutting tools, and control systems.

Factors affecting the accuracy of CNC machine tools
① Precision of the machine tool itself
Machine tool accuracy covers multiple aspects such as dimensional accuracy, motion accuracy, position accuracy, repeatability, and parallelism. High precision machine tools are the foundation for ensuring product processing accuracy.
② Tool accuracy
The tools used in high-speed CNC machining need to have sufficient hardness and rigidity to prevent bending and deformation during cutting, while also paying attention to tool selection and geometric accuracy.
③ control system
The control system of high-speed CNC machining needs to ensure accuracy and precision during high-speed motion, often using a combination of controllers and high-speed motors to make the machine tool work more accurately.
④ Processing Materials
High speed CNC machining generally uses high-strength materials such as aluminum alloys and titanium alloys, which have higher hardness and higher requirements for machining accuracy.

Common CNC machining accuracy indicators
① dimensional accuracy
CNC machining can achieve high dimensional accuracy, typically meeting tolerance requirements of ± 0.01mm or less.
② Surface roughness
The surface roughness of the parts can be controlled to meet specific requirements, usually achieving a surface roughness of Ra0.8 μ m or less, and sometimes even reaching Ra0.4 μ m or less.
③ Parallelism and perpendicularity
It can ensure the parallelism and perpendicularity of the parts, so that the relationship between each surface of the parts meets the requirements, usually achieving parallelism and perpendicularity requirements within 0.02mm.
④ Aperture accuracy
It can achieve high-precision aperture machining, including drilling, reaming, etc., usually reaching H7 level aperture accuracy, that is, the aperture is very close to the size required by the design.

Zuhui factory is a professional and well - established machining enterprise. We've been dedicated to the field of machining for many years, accumulating rich experience and strong technical capabilities. If you have any needs or questions, please feel free to contact us.