Off-campus UMass Amherst users: To download dissertations, please use the following link to log into our proxy server with your UMass Amherst user name and password.
Non-UMass Amherst users, please click the view more button below to purchase a copy of this dissertation from Proquest.
(Some titles may also be available free of charge in our Open Access Dissertation Collection, so please check there first.)
Design with spatial relationships and tolerance specification and propagation for a product modeler
Abstract
In designing a product, the product specifications are developed first which conceptually constrain the geometry and functions of the product. Subsequently, its components are designed with the form in mind to achieve the functional requirements according to the specifications required. Conventional CAD systems are made for generating the geometric form of a part. This is meant to take the place of manual drafting. However, a system such as this is incapable of capturing the non-geometric aspects of the designer's intent in a form that can be used for automatic process planning. The result is that tolerance, parts relationships, surface finish, etc. cannot be specified by the designer in the CAD environment unless some form of annotation is provided. Product Modeler (ProMod) provides a concurrent product design environment for designers to assign the product specifications onto the parts' nominal geometry through Spatial Relationships Engine. With this information, the detailed design requirements, such as, tolerance and surface finish are generated by Dimensioning and Tolerance Propagation Engine. Based on the functional requirements, the features of individual parts are extracted through a Form-Function Interpreter Engine, and are then, mapped to the Form and Function database to establish manufacturing specifications such as machines and tools selection. Design Evaluator evaluates the machinability and asemblability of features in accordance with the Design Rules, machine capability and geometric interference. Design Advisor provides a way of incorporating modifications to improve the design. Design Simulation Unit formulates the problems which come from prototype design experiments. These results are then submitted to a design evaluator for further evaluation. When the iterative design procedures have been completed, the information, Topology Model, Geometry Model, Dimension and Tolerance Model, Form-Function Model, Form-Feature Model, etc. are then created for generating the process plan. In this dissertation, a sub-unit of ProMod is developed for dealing with product design. Product specifications are assigned using spatial relationships while the components of a product are assembled together on ProMod. This will involve the development of Spatial Relationships Engine, Dimensioning and Tolerance Propagation Engine as well as integrating them firmly within the ProMod architecture.
Subject Area
Industrial engineering|Mechanical engineering|Computer science
Recommended Citation
Liu, Hsu-Chang, "Design with spatial relationships and tolerance specification and propagation for a product modeler" (1992). Doctoral Dissertations Available from Proquest. AAI9305863.
https://scholarworks.umass.edu/dissertations/AAI9305863