Innovative Ultrafast Laser Solutions

Innovative Ultrafast Laser Solutions

Long Pulse Machining Example

INVAR, an alloy formed of Nickel and Iron, has an extremely small coefficient of thermal expansion at room temperature. INVAR is often called for in the design of machinery that must be extremely stable. This sample was machined using a “long” pulse laser. The laser pulse parameters are: pulse duration 8 ns, energy 0.5 mJ. The machining was not assisted by an air jet.

It is quite obvious that the machining process under these conditions is not very clean. A recast layer can be clearly seen near the edges of the channel. Large debris are also seen in the vicinity of the cut. Note that one could have used some type of an air jet to assist in the machining process. The air jet function would be to physically project the melt phase away from the work zone. This would have resulted in a cleaner-looking cut, but also would have contaminated the sample down-stream.

A channel made in 1mm thick INVAR (nickel/iron alloy) with long (nanosecond) pulses

Figure 4.1: A channel made in 1mm thick INVAR (nickel/iron alloy) with long (nanosecond) pulses.