Do you know that CT Scanner can measure the radius of a plastic part better than a CMM?

The measuring of a rounded part radius is always a challenge. While CT (computed tomography) scanners and CMMs (coordinate measuring machines) are both valuable tools for dimensional measurement, but they operate on different principles and offer distinct advantages. When it comes to measuring the radius of a plastic part, CT scanners have some advantages over traditional CMMs:

CT Scanner Advantages for Measuring Radius in Plastic Parts:

1. Non-Destructive 3D Imaging: CT scanners create detailed 3D images of the internal and external features of a part without the need for physical contact. This non-destructive approach allows for a comprehensive analysis of the entire part, including hidden or internal features.
2. Full Surface Measurement: CT scanners capture information from the entire surface of the part, providing a complete dataset for analysis. This is particularly advantageous when measuring complex shapes, curved surfaces, or parts with intricate geometries.
3. Complex Geometry Handling: Plastic parts often have complex shapes and varying wall thicknesses. CT scanners excel at handling such geometries, providing accurate measurements even in regions that may be difficult to access or inspect using traditional methods.
4. Internal and External Radii Measurement: CT scanning allows for the measurement of both internal and external radii of a plastic part. Traditional CMMs may have limitations in accessing and measuring internal features without disassembling the part.
5. Simultaneous Measurement of Multiple Features: CT scanners can measure multiple features simultaneously, providing a comprehensive understanding of the part’s geometry. This efficiency is particularly beneficial when dealing with intricate designs or parts with numerous dimensions to measure.
6. Material Density Compensation: CT scanners can account for variations in material density when measuring radii, providing more accurate results. This is especially relevant for plastic parts where the density may not be uniform throughout.
7. Visualization and Analysis Tools: CT scan data can be visualized in 3D, allowing for in-depth analysis of the part’s structure and dimensions. Advanced software tools associated with CT scanning enable precise measurements, including radii, and facilitate detailed inspections.

CMM Considerations:

1. Contact-Based Measurement: Traditional CMMs rely on physical contact with the part’s surface using probes or styluses. While effective for certain applications, contact-based methods may not be suitable for delicate or flexible materials like plastics.
2. Limited to External Features: CMMs are typically used for measuring external dimensions and features. Internal features, especially those within complex geometries, may be challenging to access and measure accurately.
3. Time-Consuming for Complex Parts: Measuring complex parts with intricate geometries using a CMM can be time-consuming, especially when multiple measurements are required. CT scanners, on the other hand, provide a more efficient means of capturing comprehensive data.

In summary, CT scanners offer advantages in terms of non-destructive 3D imaging, the ability to measure internal and external features simultaneously, and efficient handling of complex geometries, making them well-suited for measuring the radius of plastic parts. However, the choice between a CT scanner and a CMM depends on factors such as the specific requirements of the measurement task, the nature of the material being measured, and the desired level of detail and accuracy.