Compound and Hybrid Micromachining Processes

Rahman, M.; Asad, A.B.M.A.; Wong, Yoke San; Jahan, Muhammad P.; Masaki, Takeshi

doi:10.1016/b978-0-08-096532-1.01105-5

Cited by 3 publications

(3 citation statements)

References 43 publications

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“…According to Okasha et al [39], the micro-drill's instability at the entry side is due to the unbalanced force exerted on the tool lips. During the drilling of angled holes, the drill tip is subjected to a high lateral force which causes the micro-drill to bend and eventually break the tool [44]. Okasha et al [41] suggested that the diameter of the laser pre-drilled hole should be smaller than the length of the chisel edge in order to reduce drill wander.…”

Section: Shape and Structure Of Holes Made With A Lasermentioning

confidence: 99%

“…Sequential drilling is a promising method for increasing tool life when micro-drilling Ni-based alloys [39]. According to Rahman et al [44], sequential laser and mechanical drilling can solve the problems of recast layer formation, poor geometry, and back-wall damage associated with laser drilling. Sequential laser drilling followed by mechanical re-drilling increases the tool life by approximately two times (Figure 20) compared to mechanical drilling within the range of the cutting parameters tested.…”

Section: Tool Wearmentioning

confidence: 99%

“…Sequential drilling is a promising method for increasing tool life when micro-drilling Ni-based alloys [39]. According to Rahman et al [44], sequential laser and mechanical drilling can solve the problems of recast layer formation, poor geometry, and back-wall damage associated with laser drilling. and thermal loads exerted on the drill reduce the tool life.…”

Section: Tool Wearmentioning

confidence: 99%

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An Investigation of the Sequential Micro-Laser Drilling and Conventional Re-Drilling of Angled Holes in an Inconel 625 Ni-Based Alloy

Szwajka,

Zielińska-Szwajka,

Żaba

et al. 2023

Lubricants

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The conventional (mechanical) micro-drilling of Inconel 625 alloys suffers from premature breakage of the drill bit due to its brittle nature and limited cutting tool life. Even greater problems are encountered when micro-drilling holes at an acute angle to the machining plane. In such a process, there are great difficulties associated with the low stiffness of the tool, which leads to the frequent breakage of the drill during machining. Therefore, in this type of mechanical drilling operation, the hole surface is usually milled with an end mill to provide a flat surface on the entry side of the drill bit. The aim of this article is to recognise the process of sequential micro-drilling and to assess the possibility of its use as an effective and efficient method of micro-drilling in hard-to-cut metals. The paper describes the process of initial laser drilling followed by final mechanical micro-drilling. Inconel 625 Ni-based alloy sheets were used as the test material. The shape and microstructure of pre-holes made with a laser, the volumetric efficiency of laser processing, the energy in the mechanical drilling process, and tool wear were analysed. The research results show that in the sequential drilling process, mechanical re-drilling eliminates the geometrical discrepancies resulting from the laser pre-drilling. In addition, it was found that, compared to mechanical micro-drilling, the use of sequential micro-drilling resulted in a two-fold increase in drill life. It has been also observed that sequential machining reduces the energy demand by 60% compared to mechanical micro-drilling. In addition, it was found that the edge of the drill bit is a key factor in deciding the target diameter of the laser-drilled pilot hole, and thus in selecting the micro-drilling parameters.

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Section: Shape and Structure Of Holes Made With A Lasermentioning

confidence: 99%

Section: Tool Wearmentioning

confidence: 99%

“…Sequential drilling is a promising method for increasing tool life when micro-drilling Ni-based alloys [39]. According to Rahman et al [44], sequential laser and mechanical drilling can solve the problems of recast layer formation, poor geometry, and back-wall damage associated with laser drilling. and thermal loads exerted on the drill reduce the tool life.…”

Section: Tool Wearmentioning

confidence: 99%

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