Interdependence Between Tool Misalignment and Cutting Forces in Ultraprecise Single Point Inverted Cutting

Abstract Ultraprecise single point inverted cutting (USPIC) is a microfabrication technique that has been recently developed for the generation of micro-optical microstructures with sharp concave geometries. Among the multiple challenges encountered during the micromachining process, tool alignment represents one of the critical factors affecting the overall accuracy of the microstructure that in turn affects its optical functionality. Since none of the presently available tool alignment techniques was found to perform well in the particular context of the diamond insert used in USPIC, an in-depth analysis of its mechanics was used in this study to provide insight on the interdependence between cutting tool misalignment and cutting forces. For this purpose, an experimental setup was devised to record the 3D cutting forces generated during the fabrication of two representative concave geometries delimited by planar facets. The first test geometry represents an instance of an isolated right triangular prism (RTP) whose quality and optical functionality will be significantly affected by diamond insert misalignment, particularly due to the undesirable contact to occur between the secondary/lateral cutting edges of the tool and the optically nonfunctional RTP facets. By contrast, the second test geometry had both lateral facets removed, such that the cutting conditions obtained in this case could be regarded as similar with that of the classical orthogonal cutting setup. Direct comparisons of the cutting force profiles obtained for the two cutting scenarios enable unequivocal identifications of tool misalignment direction and magnitude, such that targeted corrective actions could be performed to address the issue

Preliminary machine learning analysis and high-speed thermographic visualization of the laser polishing process

11th CIRP Conference on Photonic Technologies [LANE 2020], September 7-10, 202

Effect of initial surface topography during laser polishing process: Statistical analysis

Surface finish is one of the most important quality characteristics of fabricated components. Laser polishing (LP) is one of the advanced manufacturing surface finishing techniques that has been recently developed and successfully employed for improving surface quality without deteriorating the overall structural form through surface smoothing by melting and redistributing a thin layer of molten material. This paper advances the statistical analysis of the LP process emphasizing aspects of the effect of the initial surface topography. Flat and ground initial surfaces are used for comparative statistical analysis of initial and polished profiles obtained experimentally. Their profile geometries and surface quality characteristics, such as, roughness, were compared and analyzed. In addition, LP process was experimentally investigated as a thermodynamic operator represented by a transfer function and it was examined by means of a coherence function

Preliminary experimental analysis of the surface topography formation during laser polishing H13 tooling steel using statistical characteristics of the surface amplitude distribution

48th SME North American Manufacturing Research Conference, NAMRC 48 (Cancelled due to COVID-19

Fast and cross-vendor OpenCL-based implementation for voxelization of triangular mesh models

As the open standard for parallel programming of heterogeneous systems, OpenCL has been used in this study in the context of a particular and intensive computing task, namely the voxelization of tessellated objects. For this purpose, OpenCL platform has been utilized to develop a parallelized voxelization algorithm that relies on a fast and efficient triangular mesh facet/cube overlapping test. The extensive numerical tests conducted with heterogeneous hardware configurations on geometric objects of varying complexities, mesh/domain sizes, and voxel resolutions suggest that up to 99.6% or 260 times decrease in the computation time can be obtained when GPU- or CPU-based parallelized techniques are used instead of the conventional single-thread CPU approach. Future developments will attempt the integration of the current implementation into a virtual orthopaedic surgery platform

Axial strategy for ultraprecise single point cutting of V-grooves Case 1: constant chip thickness

47th SME North American Manufacturing Research Conference, NAMRC 47, June 10-14, 2019, Pennsylvania, US

Reduction of cutting forces by elliptical vibration in multi-pass ultraprecise single point axial cutting of V-grooves

48th SME North American Manufacturing Research Conference, NAMRC 48 (Cancelled due to COVID-19

Design of a five-axis ultra-precision micro-milling machine—UltraMill. Part 1: Holistic design approach, design considerations and specifications

High-accuracy three-dimensional miniature components and microstructures are increasingly in demand in the sector of electro-optics, automotive, biotechnology, aerospace and information-technology industries. A rational approach to mechanical micro machining is to develop ultra-precision machines with small footprints. In part 1 of this two-part paper, the-state-of-the-art of ultra-precision machines with micro-machining capability is critically reviewed. The design considerations and specifications of a five-axis ultra-precision micro-milling machine—UltraMill—are discussed. Three prioritised design issues: motion accuracy, dynamic stiffness and thermal stability, formulate the holistic design approach for UltraMill. This approach has been applied to the development of key machine components and their integration so as to achieve high accuracy and nanometer surface finish

Parallelized collision detection with applications in virtual bone machining

Background and objectives: Virtual reality surgery simulators have been proved effective for training in several surgical disciplines. Nevertheless, this technology is presently underutilized in orthopaedics, especially for bone machining procedures, due to the limited realism in haptic simulation of bone interactions. Collision detection is an integral part of surgery simulators and its accuracy and computational efficiency play a determinant role on the fidelity of simulations. To address this, the primary objective of this study was to develop a new algorithm that enables faster and more accurate collision detection within 1 ms (required for stable haptic rendering) in order to facilitate the improvement of the realism of virtual bone machining procedures. Methods: The core of the developed algorithm is constituted by voxmap point shell method according to which tool and osseous tissue geometries were sampled by points and voxels, respectively. The algorithm projects tool sampling points into the voxmap coordinates and compute an intersection condition for each point-voxel pair. This step is massively parallelized using Graphical Processing Units and it is further accelerated by an early culling of the unnecessary threads as instructed by the rapid estimation of the possible intersection volume. A contiguous array was used for implicit definition of voxmap in order to guarantee a fast access to voxels and thereby enable efficient material removal. A sparse representation of tool points was employed for efficient memory reductions. The effectiveness of the algorithm was evaluated at various bone sampling resolutions and was compared with prior relevant implementations. Results: The results obtained with an average hardware configuration have indicated that the developed algorithm is capable to reliably maintain \u3c 1 ms running time in severe tool-bone collisions, both sampled at 10243 resolutions. The results also showed the algorithm running time has a low sensitivity to bone sampling resolution. The comparisons performed suggested that the proposed approach is significantly faster than comparable methods while relying on lower or similar memory requirements. Conclusions: The algorithm proposed through this study enables a higher numerical efficiency and is capable to significantly enlarge the maximum resolution that can be used by high fidelity/high realism haptic simulators targeting surgical orthopaedic procedures