3D manufacturing tolerancing with probing of a local work coordinate system

International audienceThe safety and performance requirements for mechanisms are such that the necessary accuracy of part geometry is difficult to reach using classical manufacturing processes. This paper proposes a manufacturing tolerance stack-up method based on the analysis line method. This technique enables both the analysis and the synthesis of ISO manufacturing specifications through a new approach which relies on production specifications, adjustment specifications and their analysis to stack up the 3D resultant. The originality of the method resides in the 3D calculation for location requirements, which takes into account angular effects and probing operations on numerical-control machine-tools in order to define a local Work Coordinate System (WCS). For achieving tolerance analysis, deviations are modelled using Small-Displacement Torsor. This tolerance analysis method enables one to determine explicit three-dimensional linear relations between manufacturing tolerances and functional requirements. These relations can be used as constraints for tolerance optimization

Book of Abstracts of 11th Iberian Conference on Tribology

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Oversizing Thread Diagnosis in Tapping Operation

Automotive, railway and aerospace sectors require a high level of quality on the thread profiles in their manufacturing systems knowing that the tapping process is a complex manufacturing process and the last operation in a manufacturing cell. Therefore, a multivariate statistical process control chart, for each tap, is presented based on the principal components of the torque signal directly measured from spindle motor drive to diagnosis the thread profile quality. This on-line multivariate control chart has implemented an alarm to avoid defected screw threads (oversized). Therefore, it could work automatically without any operator intervention assessing the thread quality and the safety is guaranteed during the tapping process.This research was funded by the vice-counselling of technology, innovation and competitiveness of the Basque Government grant agreements IG-2011/0000392, ZL-2019/00720 (HARDCRAFT project) and KK-2019/00004 (PROCODA project). The work done in this paper has also received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement no. 723698 (ForZDM). Besides, this project, called IDI-20100674, was supported by the Centre for the Development of Industrial Technology answering to the Ministry of Economy, Industry and Competitiveness (Spanish Government)

Manufacturing variation models in multi-station machining systems

In product design and quality improvement fields, the development of reliable 3D machining variation models for multi-station machining processes is a key issue to estimate the resulting geometrical and dimensional quality of manufactured parts, generate robust process plans, eliminate downstream manufacturing problems, and reduce ramp-up times. In the literature, two main 3D machining variation models have been studied: the stream of variation model, oriented to product quality improvement (fault diagnosis, process planning evaluation and selection, etc.), and the model of the manufactured part, oriented to product and manufacturing design activities (manufacturing and product tolerance analysis and synthesis). This paper reviews the fundamentals of each model and describes step by step how to derive them using a simple case study. The paper analyzes both models and compares their main characteristics and applications. A discussion about the drawbacks and limitations of each model and some potential research lines in this field are also presented

Advances and Trends in Non-conventional, Abrasive and Precision Machining

The work included in this book pertains to advanced abrasive and nonconventional machining processes. These processes are at the forefront of modern technology, with significant practical significance. Their importance is also made clear by the case studies that are included in the research that is presented in the book, pertaining to important materials and high-end applications. However, the particularities of these manufacturing processes need to be further investigated and the processes themselves need to be optimized. This is conducted in the presented works with significant experimental and modeling work, incorporating modern tools of analysis and measurements

Optimizing Powder Metallurgy Methods: Carbon Nanotube Metal Composites

Since their discovery in 1991, CNTs have revolutionized the composites industries and continue to show great promise as exotic reinforcers in a variety of materials. Extensive studies have been carried out by researchers to impart the unique physical properties of CNTs in metal systems and understand their interfacial interactions. However, the thermal, electrical and mechanical advantages of CNTs in metal systems are limited because of their tendency to aggregate together in rope-like bundles. The objective of this research is two-fold: 1) optimize carbon nanotube (CNT) dispersal mechanisms in the fabrication of aluminum carbon nanotube metal-matrix composites (Al-CNT/MMCs) via the powder metallurgy method (PM), 2) characterize the effects of CNT morphology on the physical properties of Al-CNT/MMCs

Micro/Nano Manufacturing

Micro manufacturing involves dealing with the fabrication of structures in the size range of 0.1 to 1000 µm. The scope of nano manufacturing extends the size range of manufactured features to even smaller length scales—below 100 nm. A strict borderline between micro and nano manufacturing can hardly be drawn, such that both domains are treated as complementary and mutually beneficial within a closely interconnected scientific community. Both micro and nano manufacturing can be considered as important enablers for high-end products. This Special Issue of Applied Sciences is dedicated to recent advances in research and development within the field of micro and nano manufacturing. The included papers report recent findings and advances in manufacturing technologies for producing products with micro and nano scale features and structures as well as applications underpinned by the advances in these technologies

Tolerance Analysis Considering form Errors in Planar Datum Features

The paper investigates the role of planar datum features in tolerance analysis problems. Mating relations between datum planes are shown to involve translational and rotational errors, which are related to form tolerances and are usually neglected in tolerance analysis. To evaluate these errors, the contact between datum planes was simulated by a stochastic model, where two surface profiles are randomly generated and then registered to reproduce a mating condition. Concepts of fractal geometry were exploited to make the generation consistent with the autocorrelation properties of actual surfaces resulting from manufacturing processes. A simulation plan allowed to predict the amount of contact errors as a function of size, tolerance and process-related assumptions on the two features. An example of 3D tolerance chain is presented to demonstrate the relevance of form errors in the variation of assembly requirements