A channel machined in 1 mm thick INVAR, Nickel/Iron alloy under the same experimental conditions as the long pulse channel in Figure 4.1, but with ultrafast pulses. This channel was machined with 200 femtosecond pulses, 0.5 mJ energy per pulse. It is quite obvious that the channel machined with femtosecond pulses is cleaner than the sample machined with nanosecond pulses. Note also the absence of a recast layer. It is also clear that the machining process was more efficient – the channel is larger. The edges are straighter. Overall the quality of the micromachining is much higher.
Figure 6.1: A channel made in 1mm thick INVAR (nickel/iron alloy) with ultrafast (femtosecond) pulses and long (nanosecond) pulses.