Improving Cutting Tool Quality

The service life and efficiency of saw blades and other cutting tools can be determined with their profile and surface finish. Hence, it is vital to monitor these features during the design and production stages. Manufacturers often look for a quantitative measurement solution with the ability to rapidly image the form and surface dimensions of the “shark fin” shaped teeth. In the recent past, the introduction of the Contour LS-K, perfectly suited to this application, has benefited the industry.

Flaws of Conventional Methodologies

In the traditional methods used for the characterization of blades, it is mandatory to use a 3D stereo microscope to take pictures from particular angles. It was difficult to achieve precise positioning of the blade to acquire useful images. After obtaining usable images, simple photo analysis was employed to assess the pitch, defect burrs, tooth tip radii, form, and ultimately changes to the teeth during wear testing. This method highly relied on the skill and expertise of the personnel performing the measurements and was affected by human-induced inconsistencies in part positioning, and also the subjective information that was necessarily part of the final analyses. It was challenging to quantitatively compare early sets of measurement data with any new data because of these discrepancies in human analysis, data collection, and sample placement.

Benefits of Bruker Contour LS-K 3D Optical Microscope

As part of efforts to eliminate these multiple errors and enhance the reliability of data the newly launched Contour LS-K 3D Optical Microscope, in which Bruker’s LightSpeed™ focus variation technology is employed to capture form and surface properties, has been assessed. In this technology, a part with a small depth of field is vertically scanned, and proprietary algorithms are applied to the data to develop precise 3D images. Multiple display options, such as 3D imaging and 2D contour, allow a range of highly accurate analyses, together with high-quality true color images of the part (see Figure 1).

Figure 1. Vision 2D contour plot, 3D map, and color graphic display of saw teeth.

The bright field objectives of the system also enable live imaging, which helps not only in part placement but also in acquiring images from difficult-to-reach geometries that challenge other measurement methods. Multiple objective magnifications enable the user to easily select the magnification suitable for the surface being assessed. Additional off-axis lighting can be achieved with the help of a separate ring light, complementing the on-axis objective lighting and enabling a live imaging as well as a measurement result of higher quality. Lastly, through precise part fixturing, Contour LS-K can be fully automated for performing characterization of multiple parts without the need for operator intervention (see Figure 2).

Figure 2. Multiple blades mounted for automated inspection

It is highly crucial that manufacturers understand the tribology of the blades, and the potential to characterize blade wear has shown that there is usually a correlation between the form of the critical surfaces of the blade and ultimate function. Earlier, it was observed that minute variations in the critical surface dimensions of a tool could have a considerable effect on the service life of a blade. In this case, tool manufacturers observed that apart from providing critical wear data that can be monitored and compared in a reliable manner over time, the Bruker Contour LS-K 3D Optical Microscope also provided more visually explicit images when compared to traditional methodologies (see Figure 3). The problem of user dependence was also reduced and rendered transparent with the help of the reporting features integrated into the industry-standard Vision^® software.

Figure 3. Various tooth pitch measurements

Conclusion

The Bruker Contour LS-K 3D Optical Microscope exhibits high speed, accuracy, ease of use, and repeatability that eliminate the leading causes of error, enabling the user to obtain reliable data to speed up the development of new blade profiles, and also to ensure adherence to quality control standards for prevalent designs.

This information has been sourced, reviewed and adapted from materials provided by Bruker Nano Surfaces.

For more information on this source, please visit Bruker Nano Surfaces.