How to choose a roughness meter to meet the requirements of the technical process
The measurement of surface roughness is used to assess the quality of the machining and the compliance of the part with the specified parameters. This indicator affects the wear, fit of the mating elements, the operation of the seals and the stability of the assemblies as a whole. Therefore, the choice of a roughness meter should be based not on the formal characteristics of the device, but on the actual requirements of the technological process.
The first step is to determine the controlled parameters. In most cases, the Ra indicator is used, but in a number of industries additional parameters such as Rz, Rt or Rp are required. If the device does not support the required parameters, the measurement results will be unsuitable for technological control or documentation. Therefore, even before choosing a model, it is important to fix exactly which values should be measured and recorded.
The next aspect is the roughness range. Different production sites work with surfaces that differ by an order of magnitude. Rough processing, grinding and polishing require different measuring ranges and sensor sensitivity. Universal devices are not always suitable, especially if the control is carried out at the maximum tolerance values.
Measurement conditions also play an important role. Stationary devices with advanced data analysis and archiving capabilities can be used in the laboratory. Portable roughness meters that are resistant to vibrations and temperature fluctuations are more often used in workshop conditions. It is important to take into account access to the controlled surface, the orientation of the part and the possibility of installing the sensor without distortion.
Special attention is paid to the type of sensor and the length of the measurement path. An incorrectly selected probe or base length leads to a distortion of the results, especially when monitoring surfaces with pronounced undulation or periodic relief. For stable measurements, the route parameters must comply with the standards adopted for a specific type of processing.
The following practical considerations are taken into account when selecting a roughness meter:
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Support for required roughness parameters and measurement ranges
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Operating conditions: laboratory or production site
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Sensor type and compatibility with the shape of the controlled surface
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The ability to save and transfer measurement results
The issue of repeatability of measurements is equally important. The device must provide stable readings for multiple measurements on the same surface. This is especially critical in mass production, where decisions are made based on the results of the control to adjust the processing modes or stop the batch.
Selecting the appropriate roughness meter