Accuracy is a very important aspect of metal processing for prototypes and end use parts. Accuracy means that the appearance and feel of the parts you obtain are exactly the same as what you designed, with no errors that may affect mechanical functionality.

Due to the rise of CNC machine tools, metal processing is now more precise than ever before. Mechanical engineers can use computers to program the trajectory of cutting tools onto micrometers, almost eliminating inaccuracies caused by human errors. As long as the CNC machine is set up correctly, it should cut metal parts with high precision.

But there are many factors that affect the accuracy of metal processing. Machine quality, material selection, and even room temperature can all play a role, and some customers may have very different precision requirements for other customers.

What is machining accuracy?

Although precision and accuracy may seem synonymous, they have different meanings in terms of processing. Therefore, it is important to understand the meanings of the different terms we are referring to.

In the context of metal processing, accuracy is the degree to which a machine can match the measurement values specified in the design.

If the machine can cut the precise position specified in the design, then it has high precision.

If it occasionally misses the target but on average hits the correct position, then we can say it still has high accuracy.

But what's important is that a good CNC machine can not only achieve an average level

What is machining repeatability or machining accuracy?

Processing accuracy refers to the similarity of measured values between multiple attempts or multiple copies of a part.

In other words, if a machine accurately hits the same point on 100 copies of a part, it has high precision.

This is different from precision, as precision does not particularly focus on whether the "point" is the same as the one specified in the design! A machine can be very precise, even if it always cuts 3 millimeters to the left of the expected mark.

Obviously, having both accuracy and precision is important.

Accuracy means you are reaching the coordinates specified in the design, while precision means you consistently hit them on multiple units.