Water cutting and grinding disc  is water as medium , if the workpiece material is not in contact with water can not be used , for example, some paper , fabric cutting , or with a very thin low-flow head tube , or use dry laser cutting . Laser cutting and plasma cutting oil for cutting a workpiece has many problems . Water jet cutting and laser cutting compared to his advantage is cheap, generally small to be half the price . In the middle of the price they are precision plasma cutting machine . For cutting the uneven surface of the object , the laser machine with automatic tracking function for the job , oxygen bottles and acetylene gas bottles should distance of 5 meters or more, check for leaks before use , should be prepared to fire extinguishers. Ignition, turn off the oxygen valve, open the acetylene valve , ignition , the first slow the wind, the flame into a blue, about 8 centimeters, cut , open the valve quickly , it can be cut up . Tune fire cutting should pay attention: When cutting thicker materials , torch upright as possible , such as such as thinner , then tilt. Water cutting for cutting uneven surface of the object has a certain ability to adapt to nature , to the installation of parking device to avoid collision without water head , then there is more than one thousand yuan a ! Laser cutting machine laser machine above its workpiece position of the optical section also fear of collision .