Machining system and monitoring method

A monitoring method of a machining system, comprising a machining apparatus (202), comprising a cutting machine, adapted for machining a workpiece, the machining apparatus comprising a nozzle having an inlet end and an outlet end, and a monitoring device which monitors machining conditions of the workpiece and/or the machining apparatus, the monitoring device comprising a plurality of sensors, said plurality of sensors comprising a first sensor at a first location downstream of the inlet end, and a second sensor at a second location downstream of the inlet end distant from the first location which provide a first signal, a second signal respectively,

• the monitoring method comprising the steps of:
• defining, by the monitoring device, a first signature, comprising a first benchmark signature based on at least the first signal and the second signal;
• machining, by the machining apparatus, the workpiece;
• measuring, by the monitoring device, the machining conditions of the workpiece and/or of the machining apparatus by the plurality of sensors;
• computing, by the monitoring device, a second signature based on at least the first signal and the second signal measured during the machining;
• comparing, by the monitoring device, the first signature against the second signature;
• and
• communicating a message to a user based on the comparing.