Darrell Wallace

Tooling and process design to cold forge a cross groove inner race for a constant velocity joint — physical modeling and FEM process simulation

Abstract The cross groove constant velocity joint is widely used in the automotive industry. However, the production costs of the cross groove inner race (CGIR) are relatively high due to extensive machining and grinding operations. Substituting machining by cold forging would reduce costs but also imposes new challenges due to the geometric complexity of this part. The main objectives of the present study are to investigate the material flow in cold forging a CGIR and to optimize the process using a multi-action tooling concept. In order to define and improve the process conditions, physical modeling experiments and two and three dimensional FEM process simulations were performed. This investigation was performed to determine the best tooling motion that may result in the most cost effective production process. The simulation results are expected to provide relevant information for the design of the production tooling.

Investigations of different loading conditions in a high speed mechanical press

Abstract At high operating speeds, usually greater than 200 strokes per minute (spm), mechanical presses exhibit dynamic effects that may influence the process conditions. In order to maximize the advantages of high speed presses and maintain reproducible part quality, it is necessary to monitor and understand these dynamic phenomena. To study the behavior of a high-speed press under various loading conditions, a series of experiments was performed with a mechanical high speed press. This press is capable of reaching stroke rates up to 1200 spm. The goal was to simulate several real process loading conditions, by means of calibrated load cells, in order to monitor the dynamic behavior of the press. Changes in shutheight, load, and slide deflection were measured for different press speeds and tonnages. By damping the impact on the load cells, the shape of the load-time curve was made to better represent that of a real process such as blanking. The results of these tests will help to improve understanding, allowing future press applications to be set up faster and more precisely. The information gained from this study will help to improve the practical utilization of high speed presses by (a) improving instrumentation and monitoring techniques, (b) facilitating rapid and precise tool set-up, and (c) incorporating dynamic considerations in process and tool design.

A new 3D display using a dynamically reconfigurable display matrix surface

This paper presents a new three-dimensional display system using a reconfigurable projection manifold. The display surface is warped interactively into a non-planar manifold according to the scene images depth information for the current view. Scene images are projected onto the display using computer graphics and a post-process warping. We currently use two projections to provide a complete coverage of the manifold surface from oblique projection angles. In this paper, we describe the overall design issues and goals of the projector-based rendering process, introduce the algorithms to model the projection manifold surface and describe the algorithms used to create the pre-warped images from the scene image. Our current prototype is a discrete tile-based approximation to the depth manifold. We describe our experiments with two such prototypes, one using a static test configuration, and another actuated using linear motion controllers for each discrete tile. This second prototype can be configured dynamically, as the depth information in the scene changes.

Consumer and Manufacturer Design Factors for Use of Compressed Natural Gas (CNG) in American Automobiles

Despite significant research and development during the past quarter century, there has been an insignificant transition to use of compressed natural gas (CNG) vehicles. Although CNG automobiles reduce harmful emissions and reduce consumption of foreign oil, the nation has not successfully transitioned away from gasoline and diesel fuels. Therefore, the pros and cons of owning and operating CNG vehicles are explored from the consumer’s perspective. Included in this paper are isentropic compression models for single stage, 4 stage isentropic, and 4 stage with a constant temperature increase between cylinders. The models are then used to predict charging times for both residential and industrial compressors for an energy basis of 1MMBtu (1.055 GJ). The impact of CNG vehicles on US air emissions is discussed, with qualitative comparisons of CNG and oil-based emissions.Copyright

Mechanical Engineering Curriculum Improvement Using Product Lifecycle Management (PLM)

This paper discusses the alignment between industry needs and the content of a 4 year ME or MET curriculum by using Product Lifecycle Management (PLM) principles as a bridge. An initial concept for a device is used as an example throughout the 4 year curriculum, allowing the courses to progressively develop the design from concept through end-of-life by using PLM principles. The four-year curriculum discussed begins with an introduction to PLM, where the steps of a manufacturing process are described, from concept, to 3D design, to analysis, to final product to end of life. This provides the basis for a design concept that will be pursued throughout the curriculum. The four-year curriculum is then presented as a traditional engineering program with a superimposed design problem. The freshman curriculum includes the basic 3D modeling of the parts, while the sophomore classes generate the first prototype parts and beginning analyses. The junior classes progress into more involved stress and thermo/fluid analysis of the part, while the senior classes look into the mass manufacture of the part; it’s interaction with the rest of the system and the systems role in serving society. Students are well prepared for industry, with improved knowledge of design methods, manufacturing processes, life cycle issues and how these different areas can work together to make a successful design. The use of PLM as an over-arching theme brings it into the classroom in a practical hands-on way with minimal impact on the existing class content while improving the delivery by bringing continuity to the problems.Copyright