No abstract

In order to stay competitive with international markets, companies must deliver new products with higher quality in a shorter time with a broader variety of versions at minimum costs. Virtual manufacturing (VM) is quickly becoming an interesting strategy for product development. Primarily aimed at reducing the lead times to market and costs associated with new product development, VM offers a test-bed for the timeconsuming and expensive physical experimentation. In this paper, several key issues for developing a virtual turning testbed by using virtual manufacturing technology are discussed, i.e., representation of a workpiece with the capability of transferring error data used for machining accuracy prediction and reflecting the machining accuracy, representation of the swept volume of a tool for simulating turning process with high efficiency. The construction of surface topography, a basic model for machining accuracy prediction is also highlighted. The representations and relevant algorithms discussed in this paper are implemented in a virtual turning test-bed. A virtual machining and inspection system (VMIS) for ultra-precision diamond turning is presented and experiments are carried out to demonstrate it.

Due to complex process and high difficult operation for large-scale products assembly, the application of virtual assembly (VA) has an important significance and also an actual value. In this paper the key techniques of VA for large-scale complex products are proposed, and their assembly characteristics (such as their organization form, human participation, process planning and optimization and so on) are analyzed. First, a new virtual environment (VE) system considering human activities is set up. Second, an integration approach is realized to transform data from CAD to VA system, and a hybrid method on the basis of virtual reality (VR) and intelligent algorithm is applied to optimize and evaluate assembly process planning. Moreover, assembly documents generation and Web training for assembly workers are implemented. Finally, an application case of the VA system for a complex product is given, and further work is pointed out.

Maximally utilizing the capabilities offered by the feed drive systems in the CNC machining can both increase productivity and improve product quality. In this study, a framework of off-line feed rate scheduling was presented and a turning machining simulation and feed rate optimal system was developed. The system take advantage of virtual machining acquires cutting parameters and predicts cutting forces and cutting power. Constant cutting power was used as an objective to optimize feed rate, the feed rate in NC program was re-scheduled. The experiment results show that machining time is reduced and machining stability is improved by using the optimized NC program.