Ahu ÇELEBİ, Halil TOSUN, Ali Çağlar ÖNÇAĞ

An Investigation of the Deformation Patterns Due to the High-Speed Micro-Laser Drilling Process for Ti-6Al-4V Used in Aerospace Applications

Hibrit Laminer Akış Kontrolü (HLFC), sivil jet taşımacılığı uçaklarının yakıt tüketimini azaltmak için havacılık endüstrisindeki en önemli teknolojilerden biridir. Sınır tabaka emişinin neden olduğu sürtünmeyi azaltmak için uçak kanatlarının ve kuyruk düzlemlerinin ön kenarlarında küçük deliklere ihtiyaç vardır. Bu küçük deliklerin Ti-6Al-4V alaşımlarına uygulanması için çok fazla çalışmalar yapılmıştır. Mikro lazer delme işlemi uygulandığında, delinmiş deliklerin yakınlığına bağlı olarak bazı problemler ortaya çıkmaktadır. Ek olarak, geniş alanlara çok sayıda delik açarken ısıl bozulmanın en aza indirilmesi daha da zorlaşmaktadır. Bu araştırmanın amacı, mikro lazer delme işleminden kaynaklanan deformasyonu değerlendirmek ve en aza indirmek için etkili bir dizi çalışmalar geliştirmektir. Bu çalışma kapsamında galvo tarayıcıya sahip 50 W güç darbeli Ytterbium fiber lazer kullanılmıştır. Her mikro delme işlemi için atılan lazerler arası bekleme süresinin arttırılması, numunelerin her iki tarafında ağırlık kullanımının ve delinmiş numunelerin deformasyonu üzerine azot soğutmanın etkileri incelenmiştir. Delme işleminden önce ve sonra örnekler, entegre bir 3D lazer tarayıcısına sahip 6 eksenli bir kol CMM ile taranmıştır. PC-DMIS yazılımı kullanılarak deformasyon eğrileri elde edilmiştir. Sonuç olarak, bekleme süresi arttıkça numunelerde daha az deformasyon gözlenmiştir. Ek olarak, sürece azot gazı eklenmesi deformasyon minimuma indirgeme çabalarını olumlu yönde etkilemiştir.

Anahtar Kelimeler:

Micro-laser drilling, Ti-6Al-4V alloys, Aerospace applications, 3D Laser Scanning

An Investigation of the Deformation Patterns Due to the High-Speed Micro-Laser Drilling Process for Ti-6Al-4V Used in Aerospace Applications

Hybrid Laminar Flow Control (HLFC) is used in the aviation industry to reduce fuel consumption of civil jet aircrafts. Small holes are required at the leading edges of the aircraft wings and tail planes to reduce friction caused by boundary layer suction. Much research has been made in the application of drilling small holes to Ti-6Al-4V alloys. The most important of these investigations is that the thermal distortion cannot be controlled during the application of a large number of holes in huge areas and thus, it causes deformation as a result of thermal deterioration. When micro drilling is applied, some problems arise due to close proximity of drilled holes. The aim of this investigation is to evaluate the deformation due to the micro laser drilling process and develop an efficient set of certain laser parameters to minimize it. 50 W power pulsed Ytterbium fiber laser having a galvo scanner have been used during the process. The effects of increased waiting time, use of weight on both sides of the specimens and nitrogen cooling upon the deformation of the drilled samples have been investigated. Before and after the drilling process the samples have been scanned by a 6-axis arm CMM having an integrated 3D laser scanner. The deformation patterns have been obtained with the use of PC-DMIS software. As a result, as the waiting time is increased, less deformation has been observed in the samples. In addition, addition of nitrogen gas to the process has positively influenced the deformation minimization efforts.

Keywords:

Ti-6Al-4V alloys, Aerospace applications, 3D Laser Scanning, Micro-laser drilling,

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