A micro cylinder is a cylindrical metal part that guides the piston to perform linear reciprocating motion within the cylinder. The working fluid converts thermal energy into mechanical energy through expansion in the engine cylinder;the gas is compressed by the piston in the compressor cylinder to increase the pressure. The casings of turbines, rotary piston engines, etc. are often also called "cylinders." Application areas of cylinders: printing (tension control), semiconductors (spot welding machines, chip grinding), automation control, robots, etc.