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Article
Estimation of Wear Depth as an Approach to Predict Tool Service Life in Cold Forming Process

Authors: Lutfi Y. Zaidan لطفي يوسف زيدان --- Akram Mahdi Abd اكرم مهدي عبد --- Mohsin A. AlShammari محسن الشمري
Journal: DIYALA JOURNAL OF ENGINEERING SCIENCES مجلة ديالى للعلوم الهندسية ISSN: 19998716/26166909 Year: 2019 Volume: 12 Issue: 2 Pages: 13-34
Publisher: Diyala University جامعة ديالى

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Abstract

Wear phenomenon is considered as a predominant parameter in the forming processes causing the shorten tool life which in turn increases the production costs. In this study, wear depth of tool components for multi-stages of metal shell of spark plug (MSSP) manufacturing was analyzed using Archard's model with FE simulation software. The 3D geometry models were built using SolidWorks software then the models files were exported to Simufact forming software to do the settings of preprocess and FE analysis. The cylinder compression test and ring compression test were executed to get the flow stress and frictional factor respectively. Product parts dimensions, forging loads, effective stress, relative sliding velocity and contact pressure were solved and discussed. Subsequently to verify the analysis acceptance, the actual product parts measurements which obtained by coordinate measuring machine (CMM), were compared with the simulation results. It was found that the deviations of actual MSSP geometry dimensions less than (4%). Also verification is performed to forging loads at each stage which gives a good agreement between actual and FE simulation results. Finally, the wear depth of tool components were calculated for each stage using the FE software. Based on the results of wear depth from simulation and tolerance rages of actual product parts, tool service lives were predicted to find the productivities for each tool component. The results of FE simulation were compared with the CMM measurements for known productivities tool components from actual production line, which gives a good accuracy and acceptable agreement.

Keywords

Wear --- Cold Forming


Article
Synthesis of Ceramic Milling Balls by Cold Forming
إنتاج كرات الطحن السيراميكية بطريقة التشكيل البارد

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Abstract

This research work is concerned with testing several raw materials and solid industrial waste to produce ceramic milling balls by cold forming. The following materials have been tested as density promotors: Zirconia bricks (waste), phosphate concentrate, celestite concentrate and Pb-glass. Kaolin was used to provide the required plasticity for forming and feldspar as sintering agent.The balls were formed by hand and in a few tests by hydraulic pressure for comparison. The samples were dried for 24-48 hrs (120˚C) and fired under various temperatures ranging between 1000˚C and 1300˚C. Several parameters were determined including volume shrinkage, weight loss, bulk density, specific gravity, water absorption and compressive strength.The results showed that the best specifications were achieved in the balls made form 65% Zr-bricks (waste), 20% kaolin and 15% K-feldspar, fired at 1300˚C for 6 hrs soaking time. These balls had bulk density of 2.65-2.86 gm/cm3, porosity 0.14-0.54%, water absorption 0.05-0.21% and compressive strength 1350 MN/m2. Volume shrinkage after firing was 14-15% and weight loss 2.5-4.0%.These specifications are better than those of the balls formed by cold process and imported to Iraq. Whereas the imported balls formed by melt-casting of alumina show higher density and higher compressive strength. The present results also showed that forming under hydraulic pressure does not improve the density of the balls after firing whereas longer soaking time had significant impact in increasing the bulk density and improving the compressive strength, both of which reflect better sintering

يتناول هذا البحث إمكانية تحضير كرات طحن سيراميكية من خلطات مختلفة وباعتماد التشكيل البارد. استعملت المواد الآتية كمواد مثقلة: حطام الطابوق الزركوني، ركاز الفوسفات، ركاز السيلستايت وزجاج الرصاص، في حين اعتمد الكاؤولين لتحقيق اللدونة المطلوبة في التشكيل والفلدسبار كمادة مساعدة على التلبيد.تم طحن المواد بنعومة (-75) μm واجراء التشكيل يدويا وفي تجارب محددة بالكبس الهيدروليكي للمقارنة وجففت العينات بدرجة 120مْ لمدة 48-24 ساعة وحرقت بدرجات حرارة مختلفة تراوحت بين 1300-1000مْ وتم قياس التقلص الحجمي والنقصان في الوزن بعد الحرق وكذلك قياس الكثافة والوزن النوعي والمسامية وامتصاص الماء ومقاومة الانضغاط في الاجسام المحروقة لكافة الخلطات.بينت النتائج ان الخلطة الافضل هي 65 % حطام الطابوق الزركوني و %20 كاؤولين و %15 فلدسبار بوتاسي محروقة بدرجة 1300مْ ولفترة انضاج حراري 6 ساعات حيث حققت الكرات المنتجة بهذه الطريقة كثافة حجمية تراوحت بين 2.86-2.65 غم/سم3 (حسب حجم الكرة) ومسامية 0.54-0.14% وامتصاص الماء 0.21-0.05% ومقاومة انضغاط MN/m21350 وكان التقلص الحجمي بعد الحرق %15-14 والفقدان بالوزن بين التجفيف والحرق 4.5-2.5%. هذه المواصفات افضل او مقاربة للكرات المستوردة المحضرة بالتشكيل البارد غير انها اقل من تلك المحضرة بطريقة الصب من صهير الالومينا في خاصية الكثافة ومقاومة الانضغاط فقط. بينت التجارب عدم وجود افضلية للكبس الهيدروليكي في التشكيل على التشكيل اليدوي في زيادة الكثافة الحجمية في حين ان زيادة وقت الانضاج الحراري عمل على زيادة

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