1,721,069 research outputs found
Keel Optimization of the Italian 60 feet Sailboat FILA
No full textThe evolution of Product Simulation From Established Methods to Virtual Testing Prototypin
Diagnosi delle allergopatie oculari test clinici e di laboratorio:Presentazione di un caso clinico.
No full text
An Alternative Monitoring System for Online Production Control of Metal Formed Components
No full textRecently, non-contact sensor technologies are more and more often used for quality inspection tasks as well as for process monitoring in manufacturing. As a matter of fact, recent advancements in laser scanners and machine vision systems provide the potential to greatly improve the performance of Statistical Process Control (SPC) approaches. In this paper, a PC- based machine vision system, which provides rapid measurement of freeform geometric features, is presented. The measuring system is based on appropriate hardware and software modules. The hardware module consists of a laser scanning device and setup fixtures that can provide proper location and orientation for the part to be measured. The software module generates optimal scan plans so that the scanning operation can be performed accordingly. Furthermore, measurements for each geometric feature are automatically stored by the software module in order to perform on-line statistical analysis. The system described in this paper has been designed for on-line data acquisition, quality inspection, and statistical monitoring of actual manufacturing processes. To these aims, a user-friendly, menu-driven graphical interface has been implemented in order to give the operator an effective overview of the process state (either in-control or out-of-control). A real case study, related to the production of stamped metal panels in the automotive industry, is described
Wearing Evaluation in nickel super-alloys turning for the development of a predictive model for CAM Optimization
No full textNickel super-alloys are characterized by: high temperatures resistance, high hardness and low thermal conductivity. For this reason they are widely used in critical operating conditions. However, due to their excellent mechanical properties, nickel super-alloys are hard to machine. Tool wear is a major problem in nickel super-alloys machining; the high temperature at the tool rake face is a principal wear factor. Flank wear is the most common type of tool wear; it offers predictable and stable tool life evaluation. In this work, the authors present a flank wear evaluation in Inconel 718 turning, in order to develop a predictive model for CAM optimization. An appropriate database has been developed thanks to an experimental activity (V-B as a function of: the cutting time T, cutting speed S and feed rate F). The objective of the optimization procedure is to maximize the Material Removal Rate (MRR) under the constraint represented by the flank wear limit. The developed procedure operates directly on the part program code, using the original one as starting point for the application of the knowledge about the wear behaviour. After the optimization phase the given output is represented by a new part program code obtained in accordance with: the maximum MRR within the respect of the wear limi
Process Performances Evaluation Using a Specific Shape Factor in the Case of Sheet Hydroforming
No full textThe increasing application of numerical simulation in metal forming field has helped
engineers to solve problems one after another to manufacture a qualified formed product reducing
the time required. Accurate simulation results are fundamental for the tooling and the product
designs. Many factors can influence the final simulation result like for example a suitable yield
criterion [1]. The wide application of numerical simulation is encouraging the development of
highly accurate simulation procedures to meet industrial requirements. Currently, industrial goals of
the forming simulation can be summarized in three main groups [2]: time reduction, costs reduction,
increase of product quality. Many studies have been carried out about: materials, yield criteria [3, 4,
5] and plastic deformation [6, 7, 8], process parameters [9, 10, 11] and their optimization, geometry
modification of the stamped part to evaluate if process responses modifications are required,
reaching the goal to perform a virtual tryout of the whole deformation process [12]. In this paper
proper metal forming numerical model and experimental analysis have been developed in order to
foresee process responses in the case of sheet hydroforming technology. The interactions among the
process performances and its variables are the most interesting aspects of the research because their
knowledge means the possibility to drive the process feasibility which can be represented by the
absence of ruptures and/or wrinkles in the stamped component. This paper analyzes the sheet
thickness variation during the hydroforming process, according to a specifically defined “shape
ratio”, useful to characterize product’s geometry. The latter is an hydroformed product characterized
by a rectangular characteristic section with a drawing depth of 150mm, obtained by a hydroforming
operation on a blank having a hexagonal shape. The physical and numerical experimentations were
carried out on multiple geometries, different each others in punch radius and die radius, and on
multiple materials, steel FeP04 (with a thickness of 1mm and 0,7mm) and Aluminum Al6061 (with
a thickness of 0,7mm). The numerical simulation, validated by the experimental investigations
[13,14], allowed to define a relationship, specific for sheet metal hydroforming, between the defined
shape ratio and the key performance indicator, that is the percentage reduction thickness measured
on specific areas of the formed part. The development of numerical models with an high level
accuracy could give the real possibility to evaluate process feasibility with different combinations of
geometrical and materials parameters without, at the first glance, simulation but only analyzing the
specific curves (y = percentage reduction thickness, x = shape ratio
CAE tools as valid opportunity to improve quality control systems performances for sheet metal formed components
No full textExperimental springback evaluation in hydromechanical deepdrawing (HDD) of large products
No full textSpringback is a really troublesome effect in
sheet metal forming processes. In fact changes in geometry
after springback are a big and costly problem in the automotive
industry. In this paper the authors want to analyse
the springback phenomenon experimentally in sheet metal
hydroforming. Compared with conventional deep drawing,
sheet hydroforming technology has many remarkable
advantages, such as a higher drawing ratio, better surface
quality, less springback, better dimensional freezing and
capability to manufacture complicated shapes. The
springback phenomenon has been extensively analysed in
deep drawing processes but there are not many works in the
literature about springback in sheet metal hydroforming. In
order to study it, the authors have performed an accurate
measuring phase on the chosen test cases through a coordinate
measuring machine and the obtained measurements
have been utilised for the determination of springback
parameters, taking into account the method proposed by
Makinouchi et al. The authors have focused their attention
on the possibility of adopting a modified Makinouchi et al.
approach in order to measure the springback of the large
size considered test cases. Through the implemented
methodology it has been possible to calculate the values of
the springback parameters. The obtained results correspond
to the observed experimental deformations. Analysing the
springback parameter values of the different combinations
investigated experimentally, the authors have also studied
the pre-bulging influence on the springback amount
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