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What are Roughness and Contour Measurements?

Even the most precise cutting, turning, and grinding tools can generate minute surface variations known as roughness, which may be distinguishable visually or by touch. The degree of surface roughness can have significant ramifications to the performance of a component. Process, or witness marks on the micro-scale (µm), for example, may indicate potentially costly equipment variations that could impact batch-to-batch consistency. Intermediary surface assessments are required to ensure that processing equipment is operating at highly-stringent levels of precision. Contour measurements are one of the leading surface profiling methods for assessing angles, radii, and distances across a workpiece, and determining deviations from the component’s nominal profile.

Manufactured components are subject to contour measurements to ascertain whether the component is fit for use and to detect variations in processing conditions. These contour measurements tools are used to detect changes from design data to prevent the recurrent manufacture of components with sub-par performance levels and to reject unsuitable parts based on pre-defined pass/fail parameters.

This blog post will explore contour measurements and applications in more detail.

What is Contour Measurement?

Contours refer to the nominal form of a surface, excluding irregularities that could be categorized as roughness or waviness. Characterizing the contours of a surface profile is complex as it can be inherently difficult to separate waviness from general form. Contour measurements are therefore qualitative in nature, using best-fit data to assess surface profiles to within acceptable degrees of accuracy.

Full contour measurement typically require wider gauge ranges to map the surface in all planes. A contacting stylus is used to acquire the distance, horizontal, vertical, radial, diametrical, and angular dimensions of a profile to generate a 3D map of the critical points and ridges of an entire surface. Each of these parameters is assigned a nominal, minimum, and maximum value for integrated pass/fail tolerances.

Advanced contour measurements also make use of auto-dimensioning, alongside V-groove and gothic arch analysis.

Performing Contour Measurements

The Intra Touch Contour is a shop floor contouring measurement instrument with novel 18-bit electronics for industry-leading resolution. It features a fully-adjustable gauge range of 1 – 32 mm with a potential resolution as low as 0.8 nanometers (nm). This self-contained unit is equipped with a proprietary ball calibration technology, and it can perform simultaneous roughness and contour measurements using a single gauge.

This novel contour measurement system generates a 3D surface map by traversing a sensitive stylus across the surface according to distance as opposed to time. The glass scale and reading head ensure that measurements are carried out to the highest levels of precision, irrespective of wear, dirt, or slippage. Data acquired by traversing this contacting stylus across the surface is then calculated against an independent datum to determine variations from best-fit profiles.


Portable form, roughness, waveness and contour measurement tool

Applications of Contour Measurement

The Intra Touch Contour is most commonly used for contour measurement in the automotive and engineering sectors. It can reliably measure critical components to stringent pass/fail tolerances, including brake calipers, engine valves, and bearings.

Contour Measurements with Taylor Hobson

Taylor Hobson specializes in ultra-precision technology within the field of surface and form metrology. We provide an extensive range of contour measurement instruments with dedicated analytical software for cutting-edge surface mapping, providing unmatched accuracy for engineering quality control (QC) and quality assurance (QA) processes.
If you would like any more information about performing contour measurements with Taylor Hobson, please do not hesitate to contact us.

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