Ti-6Al-4V Cutting by 100W Fibre Laser in Both CW and Modulated Regime

Abstract

Titanium and its alloys are nowadays widely used in many sectors: in the medical field (orthopedic and dental ones), in the architectural field, in the chemical plants field and in aeronautic [1]. In this last field it is more and more used both for its contribution to make lightweight and time durable structures and for its compatibility with new materials, first of all Carbon Fiber Reinforced Plastics (CFRP). Cutting of titanium sheets is one of the primary requirements in the fabrication of most of the components. Laser cutting offers several advantages over conventional cutting methods. It includes narrow kerf width (minimum material lost), straight cut edges, low roughness of cut surfaces, minimum metallurgical and surface distortions, easy integration with computer numerically controlled (CNC) machines for cutting complex profiles and importantly non-contact nature of the process (suitable for cutting in hostile environments and in areas with limited access) [2]. However, due to very limited literature available on laser cutting of titanium, it is very difficult to predict the cut surface quality and optimum process parameters for laser cutting, especially when dross-free cuts are required. Laser cutting of titanium and titanium alloys needs to be carried out with an inert gas, this due to the high reactivity of the titanium with the oxygen at high temperatures [3]. However when the available power is limited, as in the present case, the use of a reactive gas (air) can help to achieve cutting speed value reasonable for industrial applications. The aim of this work is to study the cutting of Ti-6Al-4V rolled sheets 1 mm in thickness, by means of a 100 W fibre laser, (SPI-Red Power) working at wavelength  = 1090 nm. The maximum cutting speed were measured in both CW and pulsed regime at different mean power and different duration. Furthermore, the kerf geometry and the heat affected zone (HAZ) were studied decreasing the cutting speed from the maximum to the 80 % of this values. The results obtained showed that both the power and the cutting speed influence the cutting kerf geometry and HAZ. In particular the synergy of power and speed, resulting roughly into the heat input, seems to rule the whole cutting process.

Selective Laser Treatment on Cold-Sprayed Titanium Coatings: Numerical Modeling and Experimental Analysis

“…The process involves the impact of solid particles at high velocity (about 500 to 1000 m/s) on substrate surface, promoting the mechanical bonding between the two materials. [4][5][6][7][8][9] Titanium cold-sprayed coatings on aluminum components showed to be effective in enhancing corrosion resistance, wear properties, and compatibility with CFRP, without affecting the temper status of the substrate. One main drawback of the use of the cold spray process, however, is related to the micro-porosity induced within the coating layer, negatively affecting the performance of the titanium layer as corrosion barrier.…”

Statistical Approach to Fiber Laser Microcutting of NIMONIC® C263 Superalloy Sheet Used in Effusion Cooling System of Aero Engines

“…Furthermore, this characteristics are enhanced by the use of high quality short and ultrashort pulsed laser [13][14][15][16][17][18]. However, when the material thickness is limited (<1 mm), the use of a high quality fibre laser, working in CW or modulated regime, could be an economical and practical solution, as demonstrated in [19][20].…”

Laser Cutting of Aluminium Sheets with a Superficial Cold Spray Titanium Coating

“…Laser cutting offers several advantages compared to conventional cutting methods. It includes narrow kerf width (minimum material lost), straight cut edges, low roughness of cut surfaces, minimum metallurgical and surface distortions, easy integration with Computer Numerically Controlled (CNC) machines for cutting complex profiles and, above all, non-contact nature of the process (suitable for cutting in hostile environments and in areas with limited access) [12][13]. The CO 2 lasers (gas lasers) and Nd:YAG lasers (solid lasers) are mostly used for many industrial application.…”