Dynamic control method for laser spot and laser cutting system

A dynamic control method for a laser spot, applied to commissioning or laser cutting of a laser cutting head, wherein a laser spot performs reciprocating motion in an X direction and/or a Y direction in a focal plane, while performing high-frequency oscillation in a Z direction;

• a positive direction of an X axis is a horizontal direction along a plane of a to-be-cut sheet, a positive direction of a Y axis is a vertical direction along the plane of the to-be-cut sheet, and a positive direction of a Z axis is a direction perpendicular to an XY plane and right above the plane of the to-be-cut sheet;
• when a stainless steel medium plate or a stainless steel thick plate is cut, a trajectory of a spot has a diameter of 50-800 μm, the spot has a swing frequency of 50-500 Hz along the X/Y axis, a negative focal point is configured, the spot has a vibration frequency of 50-400 HZ along the Z axis, and a cutting auxiliary gas has a pressure is 5-25 bar;
• kerf information at a specified mode is obtained, wherein the kerf information at the specified mode comprises kerf information in a preset duration, and a cut surface of a kerf meets a detection index;
• a swing range in the X direction is ±8 mm;
• a swing range in the Y direction is ±8 mm;
• using an X-axis driving mechanism to ensure that the laser spot performs the reciprocating motion in the X direction in the focal plane;
• and using a Y-axis driving mechanism to ensure that the laser spot performs the reciprocating motion in the Y direction in the focal plane;
• the X-axis driving mechanism comprises a galvanometer motor deflection mechanism configured to drive a reflector component to rotate around a rotating shaft along the X axis;
• the Y-axis driving mechanism comprises a galvanometer motor deflection mechanism configured to drive a reflector component to rotate around a rotating shaft along the Y axis;
• the rotating shaft of the reflector component driven by the X-axis driving mechanism and the rotating shaft of the reflector component driven by the Y-axis driving mechanism are perpendicular to each other, and the reflector component corresponding to the X axis and the reflector component corresponding to the Y axis are independent of each other;
• wherein a swing angle a along the X axis is in a range of ±5°, and a swing angle b along the Y axis is in a range of ±5°;
• a 3D dynamic trajectory of the laser spot is as follows:
• x
• =
• tan
• ⁡
• (
• a
• )
• *
• L
• 1
• ;
• y
• =
• tan
• ⁡
• (
• b
• )
• *
• L
• 2
• ;
• and
• z
• =
• c
• *
• F
• ,
• wherein x, y, and z represent 3D coordinates of each trajectory point in the 3D dynamic trajectory from a focal point 0;
• and
• a is an angle swung by a rotating shaft of a motor along the X axis in the XY plane relative to an original position, b is an angle swung by a rotating shaft of a motor along the Y axis in a YZ plane relative to the original position, c is a displacement parameter of a lens of a numerical control system, F=(a focal length of a focusing mirror/a focal length of a collimating mirror)2, and L is a constant.