When cutting PVC (Polyvinyl Chloride) with a laser, chlorine gas is created. Chlorine gas in itself is very dangerous for human beings. It is also hazardous for the laser equipment, as chlorine gas will interact with the moisture in the air and create hydrochloric acid. This acid is very corrosive to any machine parts.
To cut metal you need higher laser power than the ones we supply, together with assist gas (generally oxygen) and special optics to stop flashback. A flashback occurs when the metal reflects the laser beam back into the laser module. Using assist gas typically gives a poor edge, which needs additional handling to finish the workpiece.
Glass absorbs laser energy and heat. It will fracture and chip because of this. These fractures also generate small glass dust, which is not hazardous for human beings.