Automated design of sheet metal punches for bending multiple parts in a single setup
Sheet metal bending is a process in which bends are formed using a combination of a punch and a die. A very large number of mechanical products such as furniture panels, shelves, cabinets, housing for electro-mechanical devices, etc. are created by using the sheet metal bending process. Bending tools need to satisfy the following two criteria: (1) tools should be able to withstand bending forces, and (2) tool shapes should be such that there is no tool-part interference. In this paper, we describe a methodology for automatically designing shapes of bending punches for bending multiple parts in a single setup. We create parametric geometric models of punches. These parametric models describe the family of possible punch shapes. Using the part geometry and parametric punch shape models, we automatically generated constraints on tool parameters that eliminate the possibility of part-tool interference. We use mixed-integer techniques to identify parameters of punch shapes that result in the maximum punch strength. Finally, we perform strength analysis of the designed punch shape using "nite element analysis methods, to verify that the designed punch shape is capable of withstanding the bending forces. 2001 Elsevier Science Ltd. All rights reserved.
Recent Advances and Future Challenges in Automated Manufacturing Planning
The effective planning of a product's manufacture is critical to both its cost and delivery time. Recognition of this importance has motivated over 30 years of research into automated planning systems and generated a large literature covering many different manufacturing technologies. But complete automation has proved difficult in most manufacturing domains. However, as manufacturing hardware has evolved to become more automated and computer aided design software has been developed to support the creation of complex geometries; planning the physical fabrication of a virtual model is still a task that occupies thousands of engineers around the world, every day. We intend for this paper to be useful to newcomers in this field, who are interested in placing the current state-of-the-art in context and identifying open research problems across a range of manufacturing processes. This paper discusses the capabilities, limitations and challenges of automated planning for four manufacturing technologies: machining, sheet metal bending, injection molding, and mechanical assembly. Rather than presenting an exhaustive survey of research in these areas, we focus on identifying the characteristics of the planning task in different domains, current research directions, and open problems in each area. Our key observations are as following. First, the incorporation of AI techniques, geometric modeling, computational geometry, optimization, and physics-based modeling has led to significant advances in the automated planning area. Second, commercial tools are available to aid the manufacturing planning process in most manufacturing domains. Third, manufacturing planning is computationally challenging and still requires significant human input in most manufacturing domains. Fourth, advancement in several emerging areas has the potential to create, in the near future, a step-change in the capabilities of automated planning systems. Finally, we believe that deploying fully automated planning systems can lead to significant productivity benefits. [DOI: 10.1115/1.3593411]
IGES - the present state and future trends
Although the Initial Graphics Exchange Specification is not without its imperfections and critics, it is widely considered to be the best format currently available for the exchange of CAD data. However, IGES is seen as an interim measure, eventually to be superseded by a new international standard. This article reviews the present state of IGES and considers likely future trends in CAD data exchange.