THE EFFECT OF CUTTER PATH STRATEGIES ON SURFACE ROUGHNESS WHEN MACHINING TITANIUM ALLOY

The article deals with the comparison and evaluation of finishing cutter path strategies when applied to one of the difficult to cut material such as Ti-alloy. The titanium alloy has been increasingly used for high performance application for oil and gas, aerospace, energy, medical and automotive industries. The importance of milling strategies outgoing from their impact on the economic aspects of production, realized using CNC machines. A planar sample was designed for the purposes of the experiment, enabling finishing cutter path strategies for shaped surfaces. Three cutting strategies were involved and compared- spiral, constant Z and line feed. For assessment of the effect of the cutting strategies three different feed rate were used. Comparison of simulated cutter path strategies and machined surface were visually inspected as well as measured surface roughness were evaluated. The constant Z cutting path strategy was found as suitable cutting strategy from point of view of surface roughness.

Fast Cutter Location Surface Computation Using Ray Tracing Cores

By using the cutter location (CL) surface, fast and stable computation of the cutter path for machining complicated molds and dies can be realized. State-of-the-art graphics processing units (GPUs) are equipped with special hardware named ray tracing (RT) cores dedicated to image processing (called ray tracing) for 3D computer graphics. Using RT cores, it is possible to quickly compute the intersection points between a set of straight lines and polygons. In this paper, we propose a novel CL surface computation method using the RT core. The RT core was originally designed to accelerate 3D computer graphics processing. For the development of software using RT cores, it is necessary to use the OptiX application programming interface (API) library for computer graphics. We demonstrate how to use the OptiX API in the development of software for CL surface computations. Computational experiments were carried out, and it was confirmed that it is possible to obtain the CL surface based on a very high-resolution Z-map several times faster than the depth buffer-based method, which has been considered to be the fastest to date.

Microlens Array Fabrication by Using a Microshaper

A simple, easy, inexpensive, and quick nonsilicon-based micromachining method was developed to manufacture a microlens array. The spherical surface of the microlens was machined using a microshaper mounted on a three-axis vertical computer numerical control (CNC) machine with cutter-path-planning. The results show the machined profiles of microlens agree well with designed profiles. The focus ability of the machined microlens array was verified. The designed and measured focal lengths have average 1.5% error. The results revealed that the focal lengths of micro lens agreed with the designed values. A moderate roughness of microlens surface is obtained by simply polishing. The roughness of the lens surface is 43 nm in feed direction (x-direction) and 56 nm in path interval direction (y-direction). It shows the simple, scalable, and reproducible method to manufacture microlenses by microshaper with cutter-path-planning is feasible.

Effects of cutter path orientations on milling force, temperature, and surface integrity when ball end milling of TC17 alloy

To explore the effects of cutter path orientations on milling force, temperature, and surface integrity, end ball milling experiments of TC17 titanium alloy were accomplished derived from different cutter path orientations. The experiment results of milling force and temperature were obtained. Combining with the thermo-mechanical coupling, this paper analyzes the impact of the cutter path orientations on the surface roughness, surface topography, in-depth residual stress, microhardness distributions, and microstructure. The results indicate that the maximum milling force is 224.24 N and the temperature is 672°C under vertical downward milling path, while horizontal downward orientation provides the lowest cutting force of 81.12 N and temperature of 493°C. The surface topography of the four cutter path orientations is basin-like shape, and the minimum surface roughness of 1.128 µm is achieved under vertical upward mode. Moreover, the maximum compressive residual stress of −491.8 MPa and the maximum residual stress layer depth of 45 µm are acquired under vertical downward milling. The maximum microhardness can arrive at 390 HV0.025 under the vertical path. Additionally, the transformation of the material microstructure remains elongated, bent, and fractured. The maximum plastic deformation layer depth is 44 µm under vertical downward milling path.

Improved Algorithm to Trace Boundary Curves on Two-Dimensional Square Meshes

In the contoured cutter path computation of a mold part, the Minkowski sum shape of the mold part CAD model and an inverted cutter model is sliced by a horizontal plane at a specific height. The cutter path can be obtained by tracing the boundary curve of the cross-sectional figure in the two-dimensional (2D) square mesh model. In the boundary curve tracing of the square mesh, the 2D marching cubes method based on the classification of the cell pattern of the mesh is typically used. We extended the classification pattern so that the existence of very small shapes in the cell, which is ignored by the conventional 2D marching cubes method, is evaluated in tracing the boundary curve. By using this technology, a robust and accurate contoured cutter path can be obtained without any increase in the computation time.

A cutter path generation strategy for helical surface machining of screw rotor

In this article, the disk mill cutter path generation strategy for the machining of complex helical surface via a currently developed minimal orientation-distance algorithm based on spatial discretization method is studied. The strategy proposed here is, first, to establish the helical surface and cutting surface in the unique coordinate system. Then, the two surfaces are divided into a series of parts by n equidistant planes, and the minimal orientation-distance algorithm is used to determine all the cutter locations. Finally, on the basis of Archimedes helical interpolation, cutter path is generated within the specified tolerance limit. The effectiveness of the proposed strategy is confirmed numerically and experimentally by a case of virtual cutting test in VERICUT software and actual machining. This strategy can be applied to a broad range of helical surface machining.