Design Rule Checker for Sheet MetalComponents using Medial Axis Transforms andGeometric
Design Rule Checker is an essential component of design automation and for making design, process planning and manufacturing concurrent. In this paper, a set of algorithms are presented for detecting design violations in sheet metal components. Violations in sheet metal components occur when holes, slots, or other features are too close to one another. These violations, if undetected during design, increase the design life cycle of the product. Thus it is very essential to detect, if not eliminate these violations at the early stages of design. Typically sheet metal components have a number of features serving various purposes which include ventilation and fastening. As the contour of the parts gets complicated and the number of features on the sheet metal part increases it is diicult to check the rules exhaustively as it may lead to combinatorial explosion. 1 The algorithm presented here, uses Medial axis transformation to decompose a given domain thus preventing a combinatorial explosion, and also provides a means to integrate the rule checker with a design adviser.
A design advisor for sheet metal fabrication
Using data gathered over many years, people working in sheet metal fabrication have compiled lists of errors that are frequently made by designers in the field. These errors (or violations) are common to the design of sheet metal components used in a wide variety of products from computer chassis to automobiles. This paper outlines the efforts to use this information to aid in the development of a rule-based design advisor for sheet metal fabrication. The design advisor is a module of Promod-S, a concurrently engineered, application-orientated product modeler that is being developed by researchers at the Automation and Robotics Laboratory of the University of Massachusetts at Amherst. The paper presents algorithms for both the identification and correction of design violations. The correction approach includes methods for updating an entire part after a feature has been modified.
Changes in Quartz During Heating and the Possible Effects on Si Production
In Si and FeSi production, the main Si source is SiO2, in the form of quartz. Reactions with SiO2 generate SiO gas that further reacts with SiC to Si. During heating, quartz will transform to other SiO2 modifications with cristobalite as the stable high-temperature phase. Transformation to cristobalite is a slow process. Its rate has been investigated for several industrial quartz sources and has been shown to vary considerably among the different quartz types. Other differences in behavior during heating between these quartz sources, such as softening temperature and volume expansion, have also been studied. The quartz-cristobalite ratio will affect the rate of reactions involving SiO2. The industrial consequences and other implications of the observed difference between quartz types are discussed. Initial studies of industrial quartz were published by Ringdalen et al. In the current work, a new experimental method has been developed, and an investigation of several new quartz sources has confirmed the earlier observed large variation between different sources. The repeatability of the data has been studied and the effect of gas atmosphere investigated. The results from the earlier work are included as a basis for the discussion.