Spatter reduction in nanosecond fibre laser drilling using an innovative nozzle

Biffi, Carlo Alberto; Previtali, Barbara

doi:10.1007/s00170-012-4402-y

Cited by 20 publications

(6 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After drilling and ultrasonic cleaning the bore diameters of 20 randomly chosen holes are measured my microscopy both on the top and the bottom side. To determine the hole circularity its diameter is measured on the minor and major axes of the equivalent ellipse and calculated by the ratio between them (Biffi and Previtali, 2012). Formula (6) is used to calculate the taper T from the hole diameter on the top side D top , the bottom side D bottom and the material thickness t (Biffi and Previtali, 2012):…”

Section: Process Stability Circularity and Tapermentioning

confidence: 99%

“…The green body ceramic had much less splatter than the sintered ceramic and no problems with cracks. Jiao et al (2014) halved splatter area during femtosecond laser drilling of silicon wafers by heating the wafer from 300 K to 773 K. Further methods to avoid splatter as drilling using special nozzles with cross jet contacting the material (Biffi and Previtali, 2012) or drilling under liquids (Jiao et al, 2011) are not commonly in practice.…”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Rapid micro hole laser drilling in ceramic substrates using single mode fiber laser

Adelmann

Hellmann

2015

Journal of Materials Processing Technology

View full text Add to dashboard Cite

Section: Process Stability Circularity and Tapermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Rapid micro hole laser drilling in ceramic substrates using single mode fiber laser

Adelmann

Hellmann

2015

Journal of Materials Processing Technology

View full text Add to dashboard Cite

“…This results in a better focussing and then higher cutting speeds with comparable or better kerf quality, in term of: small dimension, spatter and dross absence, recast layer and HAZ extension. 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].…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2015

View full text Add to dashboard Cite

In order to reduce thermal stress and avoid premature failure of turbine blades in the hot section of aero-engines, a diffusion cooling system is often adopted. This system is a thin sheet, with a closely spaced holes array allowing a uniform cooling of the turbine blade thanks to the evenly distributing of the cooling fluid within its wall. The holes diameters vary in the range of 0.3-1.0 mm. Furthermore, tight tolerances, perpendicular surfaces, no burr, no recast layer, are required. In order to satisfy the hole requirements, typically EDM technique is adopted. However, EDM micro-drilling needs long process time (about 20 s for hole). A promising alternative is laser trepanning. In this technique, a laser beam, with a very small focused spot, is used to make a hole by circular cutting. The hole is obtained in few seconds (<3 s). In this work a preliminary study on laser microcutting of NIMONIC ® C263 sheet is presented in order to verify the possibility to adopt a low-power Yb:YAG fiber laser for the microdrilling. Linear cutting tests were carried out on NIMONIC ® C263 superalloy sheet, 0.38 mm thick, using a 100 W Yb:YAG fiber laser working in modulated regime. A systematic approach based on Design of Experiment (DoE) has been successfully adopted with the aim to detect which and how the process parameters affect the kerf geometry in term of kerf width, taper angle and tolerances. The examined process parameters were scan speed, on-time, pulse duration and gas pressure. A full factorial design and ANalysis Of VAriance (ANOVA) were applied. Experimental results show the possibility to obtain kerf characterized by narrow width (<100 m), low taper angle values (<1.8°) and small tolerance (<0.22 m). Then, the possibility to produce in-tolerance holes was proved.

show abstract

“…Thus, the type of assist gases must be selected carefully depending on the laser set up and material properties. Previous laser drilling works on various materials involving assist gases are summarised in Table 2.1 , Rodden et al 2001, Khan et al 2004, Ghoreishi and Nakhjavani 2008, Okasha et al 2010, Webster et al 2010, Choudhury et al 2012, Biffi and Previtali 2013.…”

Section: Assist Gasesmentioning

confidence: 99%

“…The role of different gases on removing spatter was already summarised and discussed in Section 2.2.4. Hence, only one study (Biffi and Previtali 2013) involving an innovative gas nozzle is introduced in this section. Biffi and Previtali proposed a shielding gas nozzle which was designed to completely contact with the target material during laser drilling.…”

Section: Spattermentioning

confidence: 99%

Study of femtosecond laser pulse drilling of silicon

Jiao¹

View full text Add to dashboard Cite

Femtosecond (fs) laser drilling has been proved to be an efficient tool to drill various materials. In the drilling process, however, there are constant needs to eliminate spatter, control the taper, increase the aspect ratio and material removal rate. In addition, it is necessary to further understand the laser material interaction mechanism. In this thesis, some new features were proposed into the femtosecond laser drilling area in order to overcome these problems. In this study, the effect of six alcohol liquids on the fs laser drilling process was evaluated and compared. The relation between the volatility of the liquids and the material removal rate of laser drilling was found. A more volatile liquid could assist better in carrying away the debris and allow more laser energy to reach the ablation front. The material removal efficiency was increased by 40% when applying methanol as the assist liquid. The spatial wavelength of laser induce period surface structure (LIPSS) as fabricated in ethanol was found to be 455 nm which is about 40% less than that in air (772 nm). This finding could improve the applicability of LIPSS as optical gate and catalyst support. A systematic assessment of geometry evolution of the laser drilled through hole at different substrate temperatures was conducted. The result suggested that the entrance hole diameter was increased by 25% while the exit hole was increased by 30% when the substrate temperature was increased to 900 K. The laser drilling efficiency was also greatly increased Abstract ii by elevating the substrate temperature. This high drilling efficiency was attributed to the enhanced laser energy absorption of silicon wafer and thereafter wave guiding effect. The spatter area was found, however, to be continuously decrease with increasing the substrate temperature. This study provided useful knowledge for better understanding the fs laser 74(6): 729-739.

show abstract

Spatter reduction in nanosecond fibre laser drilling using an innovative nozzle

Cited by 20 publications

References 15 publications

Rapid micro hole laser drilling in ceramic substrates using single mode fiber laser

Rapid micro hole laser drilling in ceramic substrates using single mode fiber laser

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

Study of femtosecond laser pulse drilling of silicon

Contact Info

Product

Resources

About