Results of an industrial survey on the use of surface texture parameters

In 1999, CIRP conducted an industrial survey of the use of surface texture parameters [1]. In the seventeen years since, much has changed, with the most important advancement being the introduction of areal surface texture parameters as described in ISO 25178-2 [2]. There has also been the release of commercial software packages for the calculation of surface texture parameters and, therefore, it is expected that industry is starting to embrace areal surface texture characterisation. Industry is also increasingly using more optical instruments, which are often inherently areal in nature. These factors bring to light the need for a new parameter survey, to investigate whether industry really has been adopting areal surface texture parameters. This study used an online survey to obtain information about the current use of surface texture parameters in industry. The survey features both profile and areal surface texture parameters defined in specification standards ISO 4287 [3], ISO 25178-2 [2], ISO 12085 [4] and ISO 13565-2/3 [5, 6]. The survey was open to responses for eight months and obtained a total of 179 responses from a variety of industrial users of surface texture parameters spread across thirty-two countries. Responses from the survey offer information about the usage of individual surface texture parameters, highlighting any parameters that are unpopular and may require attention. The survey also enables participants to share their opinion on the current range of parameters in use, giving an insight into the perception of surface texture parameters in industry. The results from the survey highlight a strong adoption by industry of the areal surface texture parameters defined in ISO 25178-2. In comparison to the 1999 survey, there has also been an overall increase in the use of profile surface texture parameters, and an increase in the variety of parameters used, particularly for the ISO 4287 roughness parameters, suggesting a better understanding of the range of parameters available and their uses. Conversely, this increase in parameter variety could be due to the greater computational power available to users of surface texture parameters, allowing them to use more parameters with little cost. The results of the surface texture parameter survey will serve as an indication of the current state of the industry to those interested in the widespread acceptance and evolution of surface texture parameters. The analysis of the survey will identify common potential improvement areas in surface texture parameter selection and provide a starting point from which to better promote the current selection and better educate the users

Optimisation of surface measurement for metal additive manufacturing using coherence scanning interferometry

Surface topography measurement for metal additive manufacturing (AM) is a challenging task for contact and non-contact methods. In this paper, we present an experimental investigation of the use of coherence scanning interferometry (CSI) for measurement of AM surfaces. Our approach takes advantage of recent technical enhancements in CSI, including high dynamic range for light level and adjustable data acquisition rates for noise reduction. The investigation covers several typical metal AM surfaces made from different materials and AM processes. Recommendations for measurement optimisation balance three aspects: data coverage, measurement area and measurement time. This study also presents insight into areas of interest for future rigorous examination, such as measurement noise and further development of guidelines for the measurement of metal AM surfaces

An industrial survey on the use of surface texture parameters

In 1999, CIRP conducted an industrial survey of the use of surface texture parameters [1]. In the seventeen years since, much has changed, with the most important advancement being the introduction of areal surface texture parameters as described in ISO 25178-2 [2]. There has also been the release of commercial software packages for the calculation of surface texture parameters and, therefore, it is expected that industry is starting to embrace areal surface texture characterisation. Industry is also increasingly using more optical instruments, which are often inherently areal in nature. These factors bring to light the need for a new parameter survey, to investigate whether industry really has been adopting areal surface texture parameters. This study used an online survey to obtain information about the current use of surface texture parameters in industry. The survey features both profile and areal surface texture parameters defined in specification standards ISO 4287 [3], ISO 25178-2 [2], ISO 12085 [4] and ISO 16565-2/3 [5, 6]. The survey was open to responses for eight months and obtained a total of 179 responses from a variety of industrial users of surface texture parameters spread across thirty-two countries. Responses from the survey offer information about the usage of individual surface texture parameters, highlighting any parameters that are unpopular and may require attention. The survey also enables participants to share their opinion on the current range of parameters in use, giving an insight into the perception of surface texture parameters in industry. The results from the survey highlight a strong adoption by industry of the areal surface texture parameters defined in ISO 25178-2. In comparison to the 1999 survey, there has also been an overall increase in the use of profile surface texture parameters, and an increase in the variety of parameters used, particularly for the ISO 4287 roughness parameters, suggesting a better understanding of the range of parameters available and their uses. Conversely, this increase in parameter variety could be due to the greater computational power available to users of surface texture parameters, allowing them to use more parameters with little cost. The results of the surface texture parameter survey will serve as an indication of the current state of the industry to those interested in the widespread acceptance and evolution of surface texture parameters. The analysis of the survey will identify common potential improvement areas in surface texture parameter selection and provide a starting point from which to better promote the current selection and better educate the users

Industrial survey of ISO surface texture parameters

Results of an international survey are presented, detailing the use of surface texture parameters in industry. The survey received 179 responses from a total of 34 countries, revealing the use of a variety of parameters from ISO 4287, ISO 12085, ISO 13565-2/3 and ISO 25178-2. The survey responses show an increase in the number of users of profile parameters, and an increase in the range of surface texture parameters used, compared to the results from a similar survey in 1999, as well as a significant uptake of the new areal surface texture parameters. Individual sector usage is also discussed

Coherence scanning interferometry for additive manufacture

Additive manufacture (AM) of metal components is a rapidly maturing technology; but given the large number of interrelated process parameters, it remains difficult to control to high precision. It has been observed that processing conditions may be associated with specific features in the surface texture [1], creating a drive to achieve fast, and reliable topographic measurement of metal AM surfaces. One of the most developed metal AM processes, selective laser melting (SLM), still produces parts that exhibit rough surface textures with dense distributions of features at a wide range of lateral and vertical scales, aspect ratios, and reflective properties; with the additional complication of the presence of high slopes, undercuts and surface recesses. These features make metal AM surfaces challenging to measure by both tactile and optical means [2,3]

Attitudes to national identity among tertiary students in Melanesia and Timor Leste: a comparative analysis

"This paper presents the findings of an 18-month research project on the attitudes of tertiary students in Melanesia and Timor-Leste to national identity and key issues of nation-building. The research was conducted at tertiary campuses across four sites: Dili, Port Vila, Honiara and Port Moresby. The study examined the attitudes of the young educated elite likely to dominate the next generation of leaders and decision makers. Their views are pivotal to understanding the challenges to building a more cohesive sense of national identity and political community in Melanesia and Timor-Leste. Findings highlight the ongoing importance of family, religion and maintaining traditional customs in student conceptions of political community. Depending on the case study, they also illustrate the importance of geographical region of origin, language orientation, and gender in explaining differences in key attitudes towards national identity. This article presents a comparative analysis of those findings across the four target sites ..." - page 1AusAI

Performance assessment of a new variable stiffness probing system for micro-CMMs

When designing micro-scale tactile probes, a design trade-off must be made between the stiffness and flexibility of the probing element. The probe must be flexible enough to ensure sensitive parts are not damaged during contact, but it must be stiff enough to overcome attractive surface forces, ensure it is not excessively fragile, easily damaged or sensitive to inertial loads. To address the need for a probing element that is both flexible and stiff, a novel micro-scale tactile probe has been designed and tested that makes use of an active suspension structure. The suspension structure is used to modulate the probe stiffness as required to ensure optimal stiffness conditions for each phase of the measurement process. In this paper, a novel control system is presented that monitors and controls stiffness, allowing two probe stiffness values (“stiff” and “flexible”) to be defined and switched between. During switching, the stylus tip undergoes a displacement of approximately 18 _m, however, the control system is able ensure a consistent flexible mode tip deflection to within 12 nm in the vertical axis. The overall uncertainty for three-dimensional displacement measurements using the probing system is estimated to be 58 nm, which demonstrates the potential of this innovative variable stiffness micro-scale probe system

X-ray computed tomography of additively manufactured metal parts: the effect of magnification and reconstruction sampling on surface topography measurement

X-ray computed tomography (XCT) has recently become recognised as a viable method of surface topography measurement for additively manufactured (AM) metal parts [1–5]. AM is capable of producing internal features that are inaccessible to other surface topography measurement instruments [6,7], which makes XCT topography measurement particularly interesting to the AM community. A rigorous assessment of the ability of XCT systems to measure surface topography is, however, yet to be performed, and represents a complex challenge that must account for the large number of control variables involved in XCT measurement (e.g. voltage, current, magnification, computational corrections, filtering and surface determination). The aim of this study is to investigate the sensitivity of XCT topography measurement to some such control variables. More specifically, the effects of varying magnification (i.e. the ratio between source-to-detector distance and source-to-object distance [8]) and reconstruction sampling (i.e. the resolution of the volumetric grid filled during reconstruction [9]) are investigated. These variables have been chosen for their influence on the voxel size of the volumetric dataset, which in turn affects the extracted topography, and any subsequent texture assessment. In this work, the internal top surface of a hollow Ti6Al4V cubic artefact with an external size of (10 × 10 × 10) mm, fabricated via laser powder bed fusion (LPBF) is considered (see figure 1). Measurements are performed with geometric magnification (the first control variable) set at 5×, 10×, 20× and 50×, aligned with typical magnifications used during optical surface topography measurement. The effects of super- and sub-sampling in the volume reconstruction phase (the second control variable) are investigated using Nikon software (CT Pro). Texture parameters and reconstructed topography profiles obtained as a result of XCT measurements are investigated and compared to measurements by coherence scanning interferometry (CSI) and focus variation (FV). Datasets are bandwidth-matched [10] between instruments for the quantitative comparison of texture parameters. For profile comparison, CSI, FV and XCT areal topographies are relocated with geometric registration methods. Initial results indicate that, for selected combinations of magnification and sampling reconstruction, XCT surface topography is in agreement with topography obtained by CSI, FV and stylus measurements. The authors expect this study to provide information about how these control variables can be optimised, (with the purpose of decreasing measurement complexity and time) without significantly altering the quality of the topographic result

Measurement of internal surfaces of additively manufactured parts by X-ray computed tomography

Recent advances in X-ray computed tomography (XCT) have allowed for measurement resolutions approaching the point where XCT can be used for measuring surface topography. These advances make XCT appealing for measuring hard-to-reach or internal surfaces, such as those often present in additively manufactured parts. To demonstrate the feasibility and potential of XCT for topography measurement, topography datasets obtained using two XCT systems are compared to those from more conventional non-contact optical surface measurement instruments. A hollow Ti6Al4V part produced by direct metal laser sintering is used as a measurement artefact. The artefact comprises two component halves that can be separated to expose the internal surfaces. Measured surface datasets are compared by various qualitative and quantitative means, including the computation of ISO 25178-2 areal surface texture parameters. Preliminary results show that XCT can provide surface information comparable with more conventional surface measurement technologies, thus representing a viable alternative to more conventional measurement, particularly appealing for hard-to-reach and internal surfaces