Analysis of Delamination Factor in the Drilling of Sandwich Composites

Abstract

In this study the delamination factor forming on the in and out areas of the hole in drilling of sandwich composites fabricated by using different core materials with honeycomb geometry was analyzed. Cutting speed, feed rate, and core material type were taken as the controlling factors in the experiments carried out according to Taguchi method L18 design. The experiments were carried out on a CNC vertical machining center using TiAlN coated carbide drill with a diameter of 6,3 mm. Moreover, an analysis of variance (ANOVA) with a 95% confidence level was applied and the optimal parameters for the damages on the in and out areas were determined. Optical images of the holes were taken in all test conditions after the drilling of every two specimens, and the damage types forming on the out area of the hole were analyzed for the optimal cutting parameters.The most effective parameter on the delamination factor was the cutting rate with a contribution rate of 46% for the hole entrance zone and the feed rate with the contribution rate of 32.8% for the exit zone. In particular, the types of damage that occurred in the hole exit zone were found delamination, uncut fibers, and cracking. 

Keywords

• Sandwich composite,Delamination factor,Nomex,Taguchi method,Drilling

SANDVİÇ KOMPOZİTLERİN DELİNMESİNDE DELAMİNASYON FAKTÖRÜNÜN İNCELENMESİ

Abstract

Bu çalışmada bal peteği geometrisinde farklı çekirdek malzemelerden üretilen sandviç kompozitlerin delinmesinde delik giriş ve çıkış bölgesinde oluşan delaminasyon faktörü araştırılmıştır. Taguchi metodu L₁₈ tasarımına göre yapılan deneylerde kontrol faktörleri olarak kesme hızı, ilerleme miktarı ve çekirdek malzeme tipi esas alınmıştır. Deneyler CNC dik işleme merkezinde 6,3 mm çapında TiAlN kaplı karbür matkap kullanılarak gerçekleştirilmiştir. Ayrıca %95 güven seviyesinde varyans analizi (ANOVA) uygulanmış, giriş ve çıkış bölgeleri hasarı için optimum parametreler belirlenmiştir. Her iki numunede delme işlemi sonrasında tüm deney şartlarında deliklerin optik görüntüleri alınmış ve en yüksek kesme parametreleri için delik çıkış bölgesinde oluşan hasar tipleri incelenmiştir. Delaminasyon faktörü üzerinde en etkili parametre delik giriş bölgesi için %46 katkı oranı ile kesme hızı,  çıkış bölgesi içinse %32,8 katkı oranı ile ilerleme miktarı olmuştur. Özellikle delik çıkış bölgesinde oluşan hasar tipleri delaminasyon, kesilmemiş elyaf ve parçalanma olduğu görülmüştür.

Keywords

• Sandviç kompozit,Delaminasyon faktörü,Nomex,Taguchi metodu,Delik delme

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