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Öğe Data extraction from CAD model for rotational parts to be machined at turning centres(Scientific and Technical Research Council of Turkey, Ankara, Turkey, 1999) Aslan, Ersan; Şeker, Ulvi; Alpdemir, NedimAmong the most important data produced and stored is product data. CAD data forms one of many contributors to product data. Although in most circumstances CAD data can be processed within the CIM environment by integrated software components to produce information like manufacturing data, assembly data, etc., there are a significant number of cases where an external CAD resource needs to be processed. An external CAD resource comes in the form of a neutral file format such as DXF, IGES, STEP, etc. Extracting the necessary information from an exchange file to generate manufacturing parameters thus becomes an important task. In this paper we present the results of our research efforts which were intended to extract information from the defacto industry standard DXF files to determine features existing on rotational parts to be machined on turning centres, and later utilise this information in the context of a software package implemented to develop a post-processing expert system. The feature extraction module presented in this paper, forms part of that expert system, which is named ASALUS (Aslan, 1995) and is illustrated in Figure 1. ASALUS is designed to manage the life cycle of rotational parts from the design all the way to the production by performing process planning using a generative approach and applying post-processing for two different CNC lathes.Among the most important data produced and stored is product data. CAD data forms one of many contributors to product data. Although in most circumstances CAD data can be processed within the CIM environment by integrated software components to produce information like manufacturing data, assembly data, etc., there are a significant number of cases where an external CAD resource needs to be processed. An external CAD resource comes in the form of a neutral file format such as DXF, IGES, STEP, etc. Extracting the necessary information from an exchange file to generate manufacturing parameters thus becomes an important task. In this paper we present the results of our research efforts which were intended to extract information from the defacto industry standard DXF files to determine features existing on rotational parts to be machined on turning centres, and later utilize this information in the context of a software package implemented to develop a post-processing expert system. The feature extraction module presented in this paper, forms part of that expert system, which is named ASALUS (Aslan, 1995) and is illustrated in Figure 1. ASALUS is designed to manage the life cycle of rotational parts from the design all the way to the production by performing process planning using a generative approach and applying post-processing for two different CNC lathes.Öğe Düşük takviyeli MgO-Al kompozitlerin vakumlu infiltrasyonunda takviye oranının infiltrasyon davranışına etkisi(2009) Pul, Muharrem; Çalın, Recep; Çıtak, Ramazan; Şeker, UlviBu çalışmada 149 µm parçacık büyüklüğündeki MgO tozları % 5, 10, 15 takviye-hacim oranı oluşturacak şekilde çelik tüp içersine serbest halde yerleştirilmiştir. Farklı sıcaklıklarda 550 mmHg vakum ve 5 dakika süre ile %5 Mg ihtiva eden Al alaşımı ile infiltrasyon deneyleri yapılmış ve kompozitlerin infiltrasyon mesafeleri, gözenek miktarları, mikroyapıları ve kırılma davranışları incelenmiştir. Artan takviye hacim oranı ile infiltrasyon mesafesi ve kırılma dayanımının azaldığı, gözenek miktarının ise arttığı belirlenmiştir. Artan infiltrasyon sıcaklıkları infiltrasyon mesafesini arttırırken, kompozitlerin gözenek miktarlarını azalttığı tespit edilmiştir.Öğe Experimental investigation of the effect of cutting tool rake angle on main cutting force(Elsevier Science Sa, 2005) Günay, Mustafa; Korkut, İhsan; Aslan, Ersan; Şeker, UlviThis paper presents a study of the influence of tool rake angle on the main cutting force for machining rotational parts by sharp cutting tools. A special dynamometer was designed and produced to measure the forces for this purpose. Two strain gages were placed in the proper position onto machine tool and cutting tool. Replacements of the tool caused by cutting forces were sensed by these proper placements. The well-known material, AISI 1040, was used in the experiments. Main cutting force (F-c) was measured for eight different rake angles ranging from negative to positive and five cutting speeds while depth of cut and feed rate remaining constant. As a result of experimental evaluation, cutting force decreasing trend was observed due to rake angle increasing in positive. (c) 2004 Elsevier B.V. All rights reserved.Öğe Metal MatrisliKompozitlerinTornalanmasında İlerleme Oranının Kesici Takım Aşınma Davranışlarına Etkisi(2014) Pul, Muharrem; Şeker, UlviKompozit malzemeler, kullanım alanı hızla genişleyen mühendislik malzemeleri olup Metal MatrisliKompozitler (MMK) de bu malzemelerden birisidir. Bu çalışmada; MMK malzemelerin işlenebilirliği üzerinde bazı yorumlar getirebilmek için, karıştırmalı döküm yöntemi kullanılarak % 5, % 10 ve % 15 takviye-hacim oranlarında üretilmiş Al matrisli ve magnezyum oksit (MgO) takviyeli MMK malzemeler üzerinde, Sementit Karbür (SK) ve Kaplamalı Sementit Karbür (KSK) kesici takımlar kullanılarak işleme deneyleri yapılmıştır. İşleme deneyleri 300 m/dak kesme hızında, üç farklı ilerleme miktarı (0,075, 0,15 ve 0,225mm/dev) ve sabit talaş derinliğinde (1mm) gerçekleştirilmiştir. İşleme deneylerinden sonra, kesici takımların Tarama Elektron Mikroskobu (SEM) görüntüleri alınıp aşınma davranışları incelenmiştir ve elde edilen bulgular tartışılmıştır. Kesici takımların SEM görüntüleri değerlendirildiğinde, bütün kesici takımların uç kısmında yığıntı talaş (BUE) gözlemlenmiştir. Takım ömrü sınırlarında olamamakla birlikte, ilerleme miktarını artmasıyla SK kesici takımlarda az miktarda yanak aşınmasının gerçekleştiği sonucuna varılmıştır. Genel olarak KSK takımlar daha iyi performans göstermekle beraber takım maliyetleri açısından SK takımlarında bu tür MMK malzemelerin işlenmesinde kullanılabileceği sonucuna varılmıştırÖğe The effect of reinforcement ratio on the composite structure and mechanical properties in Al-MgO composites produced by the melt stirring method(Adcotec Ltd., 2011) Çalin, Recep; Pul, Muharrem; Çitak, Ramazan; Şeker, UlviIn this study, Al- MgO metal matrix composites (MMC) were produced with 5 %, 10 % and 15 % reinforcement- volume (R-V) ratios by the melt stirring method. In the production of composites 99.5 % pure Al was used as the matrix and MgO powders with the particle size of -105 ?m were used as the reinforcement. For every R-V ratio; stirring was made at 500 rev/min at 750°C liquid matrix temperature for 4 minutes and the samples were cooled under normal atmosphere. Then hardness and fracture strengths of the samples were determined and their microstructures were evaluated by using Scanning Electron Microscope (SEM). In general, it was observed that the reinforcement exhibited a homogeneous distribution in horizontal direction. But there is a slight inhomogeneity in vertical direction. It was determined that the increase in the R-V ratio increased the porosity and also the hardness. As for the fracture strength, the highest strength was obtained with the 5 % MgO reinforced sample.
