Gregory M. Roach

Evaluation and Comparison of Alternative Compliant Overrunning Clutch Designs

Compliance criteria are used to evaluate the general class of over-running clutches to determine which type is best suited to benefit from compliance. The criteria used in the evaluation include the presence and angle of rotation of revolute joints, the possibility for part count reduction, the presence of springs, possible reduction in weight, and the method of clutch engagement. Sprag, spring, roller or ball, and ratchet and pawl clutch types were evaluated, and the ratchet and pawl type of over-running clutch was demonstrated to be the most promising. Within this type of over-running clutch, different designs incorporating bending, tension, and compression loading of the pawls were explored to determine the best method for loading the pawls. The clutches were compared using the maximum output torque. It was determined that the clutch incorporating rigid pawls loaded in compression produced the largest output torque. The maximum output torque for this clutch was measured at 65.6 N-m.

The product design generator: a system for producing design variants

This paper presents a new design system, called a Product Design Generator (PDG). A PDG is a computer-based tool that is used to automatically create all of the design artifacts and supporting necessary information for the design of a customised product to meet the specific customers needs. The PDG works by transforming a set of customer requirements into finished designs that meet those requirements. It integrates existing computer design and information management tools to produce design variants with demonstrated productivity increases of at least two orders of magnitude. The PDG captures current design methods in a reusable form to improve the productivity in the design process. Because these best practices are reusable, the consistency and repeatability of the design process are increased. This system has the potential to transform our one-at-a-time system into a factory capable of producing customised designs for the masses.

Reducing Cycle Time and Errors in the Design and Layout of MEMS

A design methodology is presented which decreases cycle time and opportunities for error through automated execution of a consistent design procedure. The Product Design Generator (PDG) methodology is useful for existing devices with a well-established design process. Two such examples are given, the Thermomechanical In-plane Microactuator (TIM) and the micro force gauge. In both PDGs, the designer inputs a finite set of requirements which automatically updates parametric design models. The necessary analyses are then executed, and product artifacts such as a CAD file, technical document, and test procedures are generated. The application of this method reduces the opportunities for error by ten times for the TIM PDG and five times for the micro force gauge PDG. The design cycle time is reduced from hours to minutes for both devices.© 2003 ASME

A Case Study of the Product Design Generator

A Product Design Generator is a web-based tool, developed for a specific product platform, for automatically creating all of the design artifacts and supporting information necessary for the design of a particular product. The PDG is modeled as a transformation function where a set of customer requirements is transformed into finished designs that will meet those requirements. Several methods have been presented for configuring and defining a product platform and are not reviewed here. Once the concept and embodiment have been selected, scaling, reconfiguration, artifact creation, and testing must occur to complete the design. Variants of the product platform are achieved by modifying the customer requirements. The development of the transformation function must account for the envelope of variation desired to encompass the range of product family members. The development of the PDG demonstrates how this is accomplished

Reconfigurable Models and Product Templates

Over the past 25 years significant investments have been made in process technologies in an effort to increase productivity and efficiency in product development. However, the return on investment in these process technologies has not yielded the gains in productivity that would be expected. This chapter asserts that this is due to the injection of new process technologies and tools into old product development processes. Globalization and mass customization are also demanding higher levels of productivity. The solution to achieving effective returns in this area of product development lies in designing and implementing strategies that integrate and optimize the new process tools and technologies. Two primary product development strategies are emerging that integrate and optimize the new process tools; first, reconfiguration of product knowledge, artifacts and data, and second, the product continuum. The gathered data supports two conclusions. One is that product design processes that take advantage of reconfigurable models enjoy significant savings in time and cost in the model creation segment of the design process. The instantiation time for the reconfigurable models averages 3% of the time to create conventional models. As the size and/or complexity of the product increases, the potential benefit of reconfigurable models also increases. Another observation is that the reconfigurable template is an effective tool for organizing and administering design information in the process. The extra time spent setting up the reconfigurable models in the first design cycle is easily repaid through faster future design cycles, easier design information maintenance, and effective reconfiguration of previous work. Productivity as measured by reduced cycle times and increased throughput must be designed and built into the process. Our experience is showing that the keys are reconfigurable artifacts and product templates.

A New Strategy for Automating the Generation of Product Family Members and Artifacts Applied to an Aerospace Application

A major challenge in industry today is to reduce the cost and cycle time in product development while maintaining enough flexibility to adapt to changing markets. Businesses are requiring more and more flexibility in order to produce custom goods at low cost. A new strategy called the Product Design Generator is presented to provide flexible product platforms through an automated design process where product variation is built into the product development process and is achieved through scalable and in some instances modular parametric models for a given product platform embodiment. A case study of web-based Product Design Generator is presented. The axial turbine disk Product Design Generator demonstrated cycle time reduction from 500 man hours to 15 minutes. This new product development strategy has demonstrated the potential to provide engineers the ability to study more potential design solutions, reduce the number of opportunities to introduce error in the product development process, and allows companies to apply a consistent design process across the organization.Copyright