Research on Template-Based Parameterized Structure Design for Drawing Dies
The structure design of drawing dies is a very compLicated and knowledge-intensive process. This paper describes a template-based parametric design system for drawing dies which adopt template as the die design knowledge base and instantiate it to complete the design of the main components of drawing die. Some key technologies such as the template technology, the parameterization technology and the top-down assembly design technique have been studied. The template for drawing dies is defined by using the "top skeleton" assembly structure, and the associative geometry-driven design and parameter-driven design of dies structure is reaLized by adopting WAVE technique and parameterized design method. The design process of template-based drawing dies structure is estabLished and the rapid design of structure is implemented by applying UG secondary development. At last, effectiveness of our method is verified by some examples.
A novel optimal working process in the design of parametric progressive dies
The objective of this study was to establish a genetic algorithm to solve the problems of ranking the working steps in progressive dies. The working area of punch in working station of progressive die was regarded as the basic reference for gene coding. The moment generated from punch to mold center is defined as fitness function. A common method, remainder stochastic sampling with replacement (RSSR), was adopted to carry out gene reproduction process calculation. We combined the fixed crossover rate and mutation rate to be the crossover and mutation process calculation basis and then obtained the optimum process in which the total moment relative to the mold center was at a minimum. Finally, we developed a “dimension-driven” Windows graphical program written in Visual C++ as an interface for parametric input and communicated with the ACAD software through a DXF file. This system is expected to be a helpful tool for designers facing demands for higher quality, lower cost and shorter delivery time for sheet metal products.
Community refinement of glaucoma referrals
AbstractAim To describe a Manchester-based glaucoma referral refinement scheme designed to reduce the number of false-positive referrals to the hospital eye service. To report on the first years results of this scheme and its financial costs to the NHS.Methods Patients with suspected glaucoma, instead of being referred to their GP and then on to the hospital eye service, were referred to a group of specially trained community optometrists working to an agreed set of referral criteria. Those patients who did not meet the referral criteria were returned to the referring optometrist, while those who met the referral criteria were referred directly to Manchester Royal Eye Hospital. The patient's GP was informed in all cases.Results The number of suspect glaucoma cases referred to the Manchester Royal Eye Hospital was reduced by 40%. This figure is close to the percentage of false-positive referrals measured at Manchester Royal Eye Hospital prior to the onset of this study. The information accompanying referral has been improved and the scheme produces a small financial cost saving to the NHS of approximately £17 per patient.Conclusion Community refinement of suspect glaucoma offers some important benefits over the current referral pathway.