Explanatory Notes on Coordinate Measuring Machines (CMM)

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A Coordinate Measuring Machine (CMM) is a high-precision instrument widely used in the manufacturing industry for inspecting the three-dimensional geometry of parts. Its ability to deliver accurate measurement data makes it essential for quality control and precision engineering. However, the performance of a CMM greatly depends on the granite and marble components it uses.

Why Granite and Marble Are Used in CMMs

Granite and marble are preferred materials for CMM components because of their outstanding physical properties:

• High stability – ensures dimensional consistency.

• Low thermal expansion – minimizes measurement drift caused by temperature changes.

• Excellent hardness and rigidity – maintains accuracy even under long-term use.

These characteristics make granite and marble ideal for manufacturing CMM reference platforms, bases, and worktables, which are critical to precision measurements

The Importance of Geometric Accuracy

The geometric accuracy of granite components is vital for CMM performance. Key parameters include:Flatness、Parallelism、Straightness、Roundness

If a CMM’s reference surface is not sufficiently flat or has irregularities, it can cause amplified measurement errors, requiring compensation and reducing overall reliability.

The Role of Surface Quality

Equally important is the surface quality of granite and marble components. Poor processing may result in:

• Surface pits and pores

• High roughness

• Uneven polishing

These defects interfere with probe contact, lower measurement precision, and may compromise product quality and efficiency. Proper finishing processes—cutting, grinding, fine polishing, and wire cutting—are essential to achieve high-quality surfaces that meet CMM requirements.

Ensuring Long-Term Accuracy

With strict manufacturing standards and regular maintenance, granite and marble CMM components can maintain long-term accuracy, even in environments with wide temperature variations. This durability ensures reliable measurements and supports stable, efficient production processes.

Conclusion

The accuracy and surface quality of granite and marble components directly determine the performance of a Coordinate Measuring Machine. By selecting high-quality stone materials and applying precise processing techniques, manufacturers can guarantee the measurement accuracy, stability, and reliability required in modern production.