Abstract : Linear motors are suitable for applications requiring linear motion, featuring simple structure and no intermediate transmission links. This paper describes the principle of a linear motor-driven flying saw and the digital control unit for length cutting composed of a single-chip microcomputer AT89C51. Keywords: welded pipe; flying saw; linear motor; control system 1 Overview A flying saw is a device for cutting high-frequency welded pipes (steel pipes) to length while in motion. It is one of the main pieces of equipment on a steel pipe production line. Currently, flying saws are driven by pneumatic, hydraulic, and electric methods. Electric drives are further divided into thyristor-controlled DC speed-regulating drives and AC variable frequency speed-regulating drives. Baoding Sanfeng Electric Co., Ltd. developed a prototype flying saw driven by an AC linear motor in 2000, featuring a novel structure. The characteristic of a linear motor is that it can directly generate linear motion, eliminating the need for an intermediate transmission device to convert rotary motion into linear motion, unlike traditional rotary motors. This feature is particularly advantageous in applications requiring linear motion. The motion of a flying saw is a reciprocating linear motion. Using a linear motor to drive the flying saw fully utilizes the excellent characteristics of the linear motor, eliminating intermediate transmission links and simplifying the saw carriage structure. This makes the entire saw truck operate smoothly and flexibly, with significant energy savings. This linear motor-driven flying saw has been successfully tested on Unit 32 of the welded pipe experimental workshop at Baoding Sanfeng Electric Company. 2. Working Principle [b][align=center]For details, please click: Linear Motor Driven Flying Saw and its Control System[/align][/b]