Five-Axis Milling of Large Spiral Bevel Gears: Toolpath Definition, Finishing, and Shape Errors

In this paper, a five-axis machining process is analyzed for large spiral-bevel gears, an interesting process for one-of-kind manufacturing. The work is focused on large sized spiral bevel gears manufacturing using universal multitasking machines or five-axis milling centers. Different machining strategies, toolpath patterns, and parameters are tested for both gear roughing and finishing operations. Machining time, tools' wear, and gear surface are analyzed in order to determine which are the best strategies and parameters for large modulus gear manufacturing on universal machines. The case study results are discussed in the last section, showing the capacity of a universal five-axis milling for this niche. Special attention was paid to the possible affectations of the metal surfaces, since gear durability is very sensitive to thermo-mechanical damage, affected layers, and flank gear surface state.Thanks are addressed to the Department of Education, and to the Universities and Research of the Basque Government for their financial support, by means of the ZABALDUZ program. We thank also the UFI in Mechanical Engineering department of the UPV/EHU for its support to this project

Five-Axis Milling of Large Spiral Bevel Gears: Toolpath Definition, Finishing, and Shape Errors

In this paper, a five-axis machining process is analyzed for large spiral-bevel gears, an interesting process for one-of-kind manufacturing. The work is focused on large sized spiral bevel gears manufacturing using universal multitasking machines or five-axis milling centers. Different machining strategies, toolpath patterns, and parameters are tested for both gear roughing and finishing operations. Machining time, tools' wear, and gear surface are analyzed in order to determine which are the best strategies and parameters for large modulus gear manufacturing on universal machines. The case study results are discussed in the last section, showing the capacity of a universal five-axis milling for this niche. Special attention was paid to the possible affectations of the metal surfaces, since gear durability is very sensitive to thermo-mechanical damage, affected layers, and flank gear surface state.Thanks are addressed to the Department of Education, and to the Universities and Research of the Basque Government for their financial support, by means of the ZABALDUZ program. We thank also the UFI in Mechanical Engineering department of the UPV/EHU for its support to this project

A review of gerotor technology in hydraulic machines

Over the years, numerous investigations have established the gerotor fundamentals. This work aims to provide a complete review of the literature from the last decade, focusing on the articles published in the past five years on gerotor technology in hydraulic machines. The report gives a catalogue of guidelines based on the trochoidal-envelope definition, a background analysis, the worldwide distribution of articles in each continent and country and the most frequently used keywords in the field. The paper identifies state-of-the-art research, and reports on current mainstream ideas. From the historical background, this literature review reports the current approaches in gerotor pumps (geometry and performance approaches, modeling and numerical simulations), orbital motors and new concepts. The report will serve as a guide and a directory for novel engineers working with gerotor technology in hydraulic machines. Another intention of this paper is to disseminate the works of the researchers who use this technology around the world, and to provide a scenario for future international collaboration. The paper gives an account of the disparity between academia and engineering applications. There is currently very little published literature on design and production methodologies for gerotor pumps and orbital motors. Hence, the future goal is to collect recommendations that combine academia and industry expertise to make better use of these extensive studies in the fieldPostprint (published version

A Finite Element Approach to Stress Analysis of Face Gears

Face Gears have alternative gear-teeth configuration compared to Bevel Gears. Face Gear have a standard spur pinion as opposed to a bevel Gear. This work concentrates on modeling of a Face-gear, Meshed with a spur gear, using CAD Software and Finite Elements Analysis. The bending stress developed at the gear teeth is determined. Numerical results are validated using the bending stress developed between two involute spur gear

Mechanical Engineering

The book substantially offers the latest progresses about the important topics of the "Mechanical Engineering" to readers. It includes twenty-eight excellent studies prepared using state-of-art methodologies by professional researchers from different countries. The sections in the book comprise of the following titles: power transmission system, manufacturing processes and system analysis, thermo-fluid systems, simulations and computer applications, and new approaches in mechanical engineering education and organization systems

Optimization and Redesign of a Dual Rotary Cutter

This design report records the actions taken by the Spin to Win team to optimize and redesign a cutter assembly in a dual rotary sheeter, as well as design a gear reduction in the same assembly. The optimization and redesign of the cutter system focuses on two main factors, inertia and torsional stiffness. The sponsor for this project is MAXSON Automatic Machinery. Wear and tear on a machine and its parts could be costly or even jeopardize the integrity of the system. Spin to Win came up with a redesign that can theoretically decrease the inertia by up to 40% and grant an increase of the torsional stiffness of the cutter assembly. The gear reduction will change the motor that can be used to propel the system, including a 1.8 : 1 reduction allowing for a smaller motor, thus lowering the cost of the entire assembly. By lowering the inertia and increasing the stiffness of the cutter system MAXSON could see longer part life and less wear as well as lower overall system costs. The optimization and redesign solution incorporates a wheel and spoke design to add torsional stiffness and decrease inertia. The spokes are inserted along the cutter on an inner shaft and are connected to the outer shell to give the design the added stiffness in the direction of rotation. A prototype was created to show the ease of assembly of the redesign and the apparent decrease in inertia from the current cutter design. The prototype has design considerations to accommodate some of the existing hardware, so that the system integrates into the sheeter system seamlessly. The design created by Spin to Win suffered in terms of manufacturability, and a simplified design was created for testing. The tests themselves encountered unexpected difficulties flowing to the design of the tests for the available equipment. In the end, the viability of the design was not definitively proved but was suggested, paving the way for further work

A Finite Element Approach to Stress Analysis of Face Gears

Face Gears have alternative gear-teeth configuration compared to Bevel Gears. Face Gear have a standard spur pinion as opposed to a bevel Gear. This work concentrates on modeling of a Face-gear, Meshed with a spur gear, using CAD Software and Finite Elements Analysis. The bending stress developed at the gear teeth is determined. Numerical results are validated using the bending stress developed between two involute spur gear

A Finite Element Approach to Stress Analysis of Face Gears

Face Gears have alternative gear-teeth configuration compared to Bevel Gears. Face Gear have a standard spur pinion as opposed to a bevel Gear. This work concentrates on modeling of a Face-gear, Meshed with a spur gear, using CAD Software and Finite Elements Analysis. The bending stress developed at the gear teeth is determined. Numerical results are validated using the bending stress developed between two involute spur gear

Comparative study of flank cams manufactured by WEDM and willing processes

Cam-follower mechanisms are usually employed in different machines, like combustion engines, sewing machines, machine tools, etc. In the present paper, the option to manufacture cams utilizing wire electrical discharge machining (WEDM) has been considered. For this, surface roughness and shape error of cam profiles manufactured by the processes of milling and wire electrical discharge machining (WEDM) are presented. The methodology used covers dfferent stages: design, prototyping, manufacturing, and measurement of the cams. As a reference, a cam-follower mechanism from a motorcycle internal combustion engine has been used. A reverse engineering process has been performed to determine the geometrical parameters of the mechanism, which are used for the synthesis of the profile of the cam and its subsequent design. The manufacturing process of the cams has been assisted by CAD-CAM (Computer Assisted Drawing-Computer Assisted Manufacturing) software. Using fused filament fabrication (FFF), a physical prototype of the cam has been manufactured, in order to validate the goodness of the design. Finally, the roughness and shape parameters have been measured on the contour surface of the cams. The arithmetical mean roughness Ra value of the milled cam was 0.269 µm, below the requirement of 0.4 µm, and shape error was 18 µm, below 50 µm. Shape error of the WEDM cam of 48 µm meets the requirements for cams. However, the Ra value of 1.212 µm, exceeded the limit. For this reason, a finish operation is recommended in this case. Some advantages of WEDM cams over milled cams are that diferent conductive materials can be employed, more complex shapes can be obtained, and that, in rough operations, the amount of material to be removed in subsequent operations is considerably reduced.Postprint (published version