0000000000267579
AUTHOR
L. D’acquisto
Springback effect evaluation in three-dimensional stamping processes at the varying of blankholder force
The quantitative evaluation of elastic springback in sheet metal stamping processes is still today a very interesting research topic, since this phenomenon causes a manufacturing shape defect. A measurement technique based on the shadow moiré method, already developed by the present authors, has been further upgraded and applied to evaluate the springback phenomenon in the deep drawing of square boxes, the basic three-dimensional stamping process. In particular this technique is able to determine the final lateral surface of the drawn parts, once extracted from the dies, and to compare such surface with the ideal one derived from the die's computer-aided design (CAD) geometry. Proper quant…
An Optical Technique for Springback Measurement in Axisymmetrical Deep Drawing Operations
Abstract In this paper, a measurement technique based on the shadow moire method has been set up to evaluate the springback phenomenon in deep drawing operations. Two proper coefficients are introduced to quantitatively describe the investigated effect. In particular, the proposed technique is able to acquire the final profile of the drawn parts along one or more lateral contour, once extracted out from the dies, and compare such profile with the ideal one derived from the dies CAD geometry. The proposed technique has been applied to an axisymmetrical deep drawing operation, and, moreover, the influence of the blankholder force level and lubricating conditions has been taken into account. T…
Contact between the components of a knee prosthesis: numerical and experimental study
The aim of this work is the analysis of the contact area in a knee prosthesis using two different approaches. In particular, the interface between the femoral component and the polyethylene insert has been studied both numerically and experimentally. The interest in studying the contact area is related to the fact that the wear of the polyethylene insert, due to the high contact pressures, represents one of the major causes of failure of the total knee prosthesis. The possibility to evaluate the contact area at different loads and mutual position between femur and tibia is, therefore, of fundamental importance to study the service life of a prosthesis and to improve its performance. The fin…
Springback Evaluation In Basic Sheet Metal Stamping Processes
In the present paper a measurement technique based on the shadow moire method has been set up in order to evaluate the springback phenomenon in deep drawing operations. Two proper coefficients are introduced to quantitatively describe the effect considered. In particular the proposed technique is able to acquire the final profile of the drawn parts along one or more generatrices, once extracted out from the dies and to compare such profile with the ideal one derived from the dies CAD geometry. The proposed technique has been applied to an axysimmetrical deep drawing operation and moreover the influence of the blankholder force level and of the lubricating conditions have been taken into acc…
Full field automated evaluation of the quarter wave plate retardation by phase stepping technique
Quarter wave plates are optical elements commonly used in photoelasticity to obtain circularly polarized light. They divide the incident light field into two linearly polarized orthogonal components with a phase difference of a quarter of the light wavelength. Due to the tolerance in manufacturing, however, the actual phase shifting produced by the plates is affected by an error, which noticeably influences the photoelastic measurements performed by means of various automated methods. This paper presents a technique, based on the phase stepping method, for the full field automatic evaluation of the quarter wave plate error.
Thermal Characterization of Friction Stir Welded Butt Joints
In the paper the thermal characterization of friction stir welding processes (FSW) of aluminium alloys is presented. In particular both embedded thermocouples and a thermography analysis were utilized in order to acquire the temperature vs. time curves in point of interests of the joints and the temperature distributions, respectively. Such kind of results are very important in order to investigate the material conditions during the FSW process.