A method for synchronous and specified-length cutting of continuously-formed materials by multiple lathes connected in series in production lines of continuously-formed materials, such as steel pipes and steel sections. A synchronous and specified-length cutting machine having multiple lathes connected in series is provided with two or more lathes that are separately equipped with a cutting tool. The lathes are installed in series on a rail parallel to a material and are driven by respective driver means to move back and forth according to a set procedure; in the case that the speed of the lathe is synchronous with that of the material, the cutting tool on the lathe cuts the material according to a specified length. The cutting machine can be adapted to high-speed production lines, allows a small minimum specified length, possesses cutting tools having a long service life, and achieves smooth cuts.

A machine for cutting a moving object comprises a conveyor belt for carrying the object along an advancement direction at a line speed and comprises a driving and cutting unit configured to move in a cutting cycle according to a forward phase in order to perform the cutting of the moving object, and configured to move according to a return phase in order to return into the initial position of the cutting cycle. The cutting machine further comprises a processing unit configured to generate a driving signal for controlling the movement of the driving and cutting unit with an acceleration trend wherein the maximum absolute value of the acceleration within the return phase is smaller than the maximum absolute value of the acceleration within the forward phase.

A machine for cutting a moving object comprises a conveyor belt for carrying the object along an advancement direction at a line speed and comprises a driving and cutting unit configured to move in a cutting cycle according to a forward phase in order to perform the cutting of the moving object, and configured to move according to a return phase in order to return into the initial position of the cutting cycle. The cutting machine further comprises a processing unit configured to generate a driving signal for controlling the movement of the driving and cutting unit with an acceleration trend wherein the maximum absolute value of the acceleration within the return phase is smaller than the maximum absolute value of the acceleration within the forward phase.

A method and device provides for alternately cutting off material by back-and-forth movement of multiple vehicles. Specifically, the device is a cut-off machine for alternately cutting off material by back-and-forth movement of multiple vehicles. The cut-off machine is at least provided with two cutter vehicles, wherein these vehicles are installed on tracks parallel to material. The tracks are arranged around the material side by side. Each vehicle moves back and forth in accordance with a set sequence. Cutters on the vehicles alternately cut off the material in accordance by a set length. The larger the number of vehicles, the longer the possible stroke of each vehicle can be, such that the cutters have more time to cut off the material. Accordingly, the cut-off machine can be adapted to higher material forming speeds in a production line.