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۱An Experimental Investigation of Surface Quality and Defects of Profiles in Wood–Plastic Composite Extrusion Process
اطلاعات انتشار: کنفرانس بین المللی فرآورش پلیمرها، سال
تعداد صفحات: ۴
A problem that usually occurs in production of extruded parts of polymeric and in special wood–plastic composite (WPC) is flow instabilities at the extrusion die exit. In this paper influence of the important parameters of material and process on the surface quality (roughness) of extruded parts are investigated. The variable parameters are wood content, polymer melt flow index (MFI), screw speed, melt temperature, die diameter and finally length–to–diameter ratio of the die land. The Instabilities of die exit flow cause to defects on surface of profiles. The experiments specified that increasing die land length–to–diameter ratio (L\D), die temperature and wood content and decreasing screw speed and polymer MFI lead to improve the surface quality.<\div>

۲Experimental Study on theEffect of Melt Flow Index on Properties of Virgin and Reprocessed Wood–HDPE Composites
اطلاعات انتشار: کنفرانس بین المللی فرآورش پلیمرها، سال
تعداد صفحات: ۴
Wood–Plastic Composites consist of wood particles and a thermoplastic matrix such as PE, PP and PVC. Among the thermoplastics,high density polyethylene (HDPE) is more favorable since the processing temperature can be maintained low enough to avoid wood burning. Various grades of HDPE with different melt flow indexes (MFI) are available by the suppliers to be used in WPC composition which may result differences in final product properties.The aim of this study was to understand the role of matrix MFI on the recycle ability of WPCs produced via the extrusion process. Three grades of HDPE with low, middle and high MFI, respectively named as LMFI, MMFI and HMFI (0.45, 7 and 20 gr\10min), were used as the polymeric matrixto produce rod shaped profiles of WPC with 60 %wt. wood content. For reprocessing, produced WPC profiles were ground andwood–plastic granules obtained. Mechanical properties were obtained from tensile test. In addition, water uptake measurements were also carried out. The results show thatreprocessed WPCs with HMFI HDPE showpoorer properties in comparison tothose of non–reprocessed ones. On the other hand, interestingly results showed that reprocessed profiles with LMFI and MMFI HDPE reveal improved properties from mechanical aspects.<\div>

۳INVESTIGATION OF THE EFFECT OF CONTACT PATTERN POSITION AND THE WORM WHEEL TEETH ON THE WORM GEARS PERFORMANCE
نویسنده(ها): ، ،
اطلاعات انتشار: کنفرانس ملی مهندسی مکانیک ایران، سال
تعداد صفحات: ۱۰
This paper is focused on the performance of worm gears influenced by the position of the contact pattern. By decreasing in size of the contact pattern area the lubricant film thickness between worm and worm wheel teeth will be decreased and lubricant temperature as a criterion for worm gears performance will be increased. In this experiment by designed tests, the effect of Contact Pattern Position of the Worm Wheel Teeth on the Lubricant Temperature behavior had been investigated. By considering the performed studies on statistical results of the amount of percentage of contact area in every tooth of under experiment worm wheel, the cause of unexpected lubricant temperature rise which leads to poor performance of transmit system had been surveyed. In continuance to increase the reliability of experiments results, the results compared with relations which are presented by some worm gears standards.Text of the abstract limited to 200 words.<\div>

۴OPTIMIZATION OF CONTACT PATTERN POSITION ON THE WORM WHEEL TEETH BY AXIAL SHIFT IN WORM WHEEL AXIS
نویسنده(ها): ، ،
اطلاعات انتشار: کنفرانس ملی مهندسی مکانیک ایران، سال
تعداد صفحات: ۶
In industrial applications Lubricant temperature decrease is a desired aim in the case of lubricant and gears performance. In this paper the procedure of optimization of worm gears performance by considering the proper contact pattern position had been performed. In accordance with required axial shift in worm wheel axis the contact pattern optimized and as a result the lubricant temperature decreased. This procedure leads to increase gears efficiency and their effective life<\div>

۵OPTIMIZATION OF MACHINING VARIABLES USING MULTI–OBJECTIVE MICRO GENETIC ALGORITHM
اطلاعات انتشار: کنفرانس ملی مهندسی مکانیک ایران، سال
تعداد صفحات: ۱۳
The selection of optimum cutting parameters has a significant role in machining process. In this work, the new method of multi–objective algorithm of micro genetic, is considered to deliver optimized cutting variables for turning process of steels. Cutting speed, feed and depth of cut as well tool geometry (rake angle and nose radius) are defined as independent variables. Several machining experiments were performed. Output results which are surface roughness and tool life were optimized simultaneously by an optimization software program written using Visual Basic in order to obtain the optimized parameters<\div>
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