Surface metrology, which can also be referred to as surface measurement, is an area of science involved in the measurement and characterization of a surface’s topography. To gather this information, surface metrology combines surface shape, finish, profile roughness, area roughness, texture, asperity and characterization data. Traditionally, surface metrology techniques have been achieved through direct contact with the sample’s surface.
A Review on Surface Metrology
Over the past two decades, a significant amount of progress has been made within the field of surface metrology. More specifically, researchers in this area have transitioned from strictly contact instruments and profile characterization to the widespread use of optical instruments and areal characterization. As research in this area continues to move forward, it is imperative for surface metrology techniques to be capable of achieving greater accuracy levels, more rapid measurement speeds and increased intelligence process control, each of which should remain consistent over a greater area coverage.
The Effect of Argon Pollution on Weld Surfaces
A 2015 paper incorporated surface metrology techniques to establish whether the pollution of argon shield gas, combined with some oxygen concentrations, affected the width of the heat-affected zone. Furthermore, the researchers determined through the use of three dimensional (3) optical measurement techniques that the argon gas, which formed a shield around the weld sample, contributed to an asymmetry and clear discoloration of the weld’s surface. The researchers of this study determined that their technique could prove useful for future surface pollution studies regarding bacteria and corrosion surface contamination.
Surface Contamination Metrology Methods
Surface contamination can be detected through a variety of analytical methods, of which depends on whether the contamination is suspected to be fixed or loose. While fixed contamination is less likely to cause internal hazards to arise, abrasion of the potentially contaminated surface could cause the contaminants to resuspend. On the other hand, loose contamination almost always causes some type of internal hazard to occur. When loose contamination of a surface is suspected, it is recommended that researchers act quickly to prevent the contamination from spreading throughout the surface and potentially causing injury to personnel.
One of the most common and successful ways of evaluating surface contamination involves direct contamination monitoring through the use of a specified detector. When placed over the surface of a potentially contaminated sample, the detector can provide important information on the classification and location of the contaminant. Surface contaminant monitoring detectors can include a direct probe, as well as indirect dry or damp wipes.
The Rise of Information Rich Metrology (IRM)
As research in the field of surface metrology continues to progress, a particular emphasis has been made on the development and enhancement of an approach known as information rich metrology (IRM). While not a single technique on its own, IRM encompasses various different concepts and methods used within the metrology industry, each of which focuses on how surface measurement procedures can be improved.
IRM utilizes information obtained from all aspects of the industrial process, of which includes the manufacturing process and the specific physical properties of the object of interest. These informative components can come from various sources, such as mathematical modeling, simulation or other metrology measurement processes, in order to gather as much information on the specific product is available. Through the IRM approach, researchers can gain a considerable amount of information regarding the stability of their sample’s surface, as well as its ability to withstand contamination, pollution or other types of unwanted effects, without potentially compromising the actual sample’s surface.
- Krolczyk, G. M., Nielsony, P., Krolczyk, J. B., Samardzic, I., et al. (2015). Influence of argon pollution on the weld surface morphology. Measurement 70; 203-213. DOI:10.1016/j.measurement.2015.04.001.
- “Measurement of surface contamination” – NPL
- “Information-rich surface metrology” – Commercial Micro Manufacturing