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49. Minimizing the springback effect in dual-phase steel parts by Finite Elements Method
Tiago Resende Gomes, Francisco J. G. Silva, Raul D. S. G. Campilho
Azevedos Indústria SA, Portugal
Developments in the automotive industry, has been over the years increased in order to increase safety and comfort, and reduce the weight of automobiles. These conditions imply the use of materials with high strength, but at the same time be lighter.
The use of Dual-Phase steels in this field, allows not only get the required conditions, as well as be more competitive, since most of the current industries using "soft" steels, more easily formable. However, taking into account the characteristics of these materials is their rather complicated stamping process, especially with regard to springback.
This work was done in order to better learn these steels and their production process through simulation software that predicts the results of stamping and minimize problems resulting from this process.
It was verified that the use of simulation software, allowed anticipate and reduce the problems associated with springback, and thus facilitate the perception and monitoring of these steels. Consequently, it was confirmed that the realization of simulation of parts and respective compensation tools can reduce time and costs in the preparation of tools.
52. Selection of Force Creation Method for Press Forming Machinery
Jarno Tolvanen, Ville Leminen, Panu Tanninen, Juha Varis, Sami Matthews
Lappeenranta University of Technology, Finland
Environmental aspects have become increasingly important in today's business. In packaging industry this has created an increased demand for fibre-based packaging solutions which present a renewable and environmentally friendly alternative for oil based materials. One of such materials is paperboard, and for example trays made of paperboard can be an alternative for traditionally used plastic trays in food packaging. Nowadays there is a need for cost-effective small scale machinery. In this study the objective was to define the best method to produce the force needed in the compact paperboard tray pressing machine. The machine has to match the demanding requirements about force production, accuracy and also hygienic requirements.
Two different force creation methods were studied in this article using Score Table -analysis and SWOT-analysis.
Results indicate that the electric actuator system had several key features compared to the hydraulic system that gave it a clear advantage, including high force production, accuracy and cost efficiency.
15. A cross wedge rolling process for forming 70 mm diameter balls from heads of scrap railway rails
Zbigniew Pater, Janusz Tomczak, Tomasz Bulzak
Lublin University of Technology, Poland
The paper describes an innovative technique for producing balls which are used as grinding media in ball mills. With this method, balls are formed from heads of scrap railway rails. The proposed two-stage technique is based on cross wedge rolling. First, a rail head is formed into a cylindrical bar with a diameter of 52 mm. Next, the bar is formed into four balls, each with a diameter of 70 mm. Given the two-stage design of the process, an innovative flat-wedge reversing mill had to be designed. The paper presents the design of such a mill. In addition, it also reports the numerical findings and experimental results of producing balls by the proposed technique.
290. Hybrid Cooling and Lubricating Technology for CNC Milling of Inconel 718 Nickel Alloy
Alborz Shokrani, Vimal Dhokia, Stephen T Newman
University of Bath, United Kingdom
High material strength, creep and corrosion resistance have made nickel based alloys an attractive material for aerospace, gas turbine and marine industries. It is reported that approximately 80% of the super alloys used in aerospace industries are nickel based alloys. This accounts for over 50 wt.% of materials used in an aero engine. Inconel 718 is the most widely used alloy of nickel and forms 35% of annual volume production of nickel alloys. Due to the high material strength and work hardening tendency of Inconel 718, high temperatures and forces are produced during cutting operations. Low thermal conductivity of the material prevents effective heat dissipation resulting in very high temperatures at the cutting zone. These high temperatures together with high cutting forces can lead to significantly reduced tool life and poor surface quality of machined parts. The surface quality is particularly important as it affect the service life and performance of the machined parts mostly used in aero engines and gas turbines. As a result, machining components made from nickel based alloys is usually associated with low cutting speeds, low productivity and high machining costs. There are a limited number of studies, predominantly on turning operations that have stated that cryogenic cooling is an effective technique for reducing the cutting temperature and as a result improving the surface integrity and allowing for higher cutting speeds to be used. This paper presents one of the very first studies on the effects of hybrid cryogenic cooling combining liquid nitrogen coolant and vegetable oil lubricant on the machinability of Inconel 718 in CNC milling. A series of experimental investigations are conducted under different cutting environments, namely cryogenic and conventional dry and emulsion. Chip morphology and surface integrity of the machined parts is then studied and statistically analysed. The analysed results are then presented in order to identify the effects of cryogenic cooling in CNC milling as compared with conventional flood cooling.