Laser welding apparatus and laser processing device

A laser welding apparatus that joins a first resin member, which is formed of a laser beam-transmissive resin and includes a first contact surface, and a second resin member, which is formed of a laser beam-absorbing resin and includes a second contact surface, by melting the first contact surface and the second contact surface with a laser beam in a state in which the first resin member and the second resin member are arranged one upon another with the first contact surface contacting the second contact surface, the laser welding apparatus comprising:

• a clamping unit that abuts at least one of the first resin member or the second resin member, which are arranged one upon the other, to apply clamping force to the at least one of the first resin member or the second resin member;
• a laser emitter that emits the laser beam transmitted through the first resin member;
• a laser controller that controls a laser output of the laser beam emitted from the laser emitter;
• a displacement sensor that measures displacement of at least one of the first contact surface or the second contact surface in a direction in which the first resin member and the second resin member are arranged one upon the other;
• and
• a control unit that continuously or intermittently obtains a displacement amount of the at least one of the first contact surface or the second contact surface from the displacement sensor and controls the clamping unit to increase or decrease the clamping force in accordance with the obtained displacement amount of the at least one of the first contact surface or the second contact surface, wherein:
• when the control unit detects a change in the displacement of the at least one of the first contact surface or the second contact surface resulting from thermal expansion of the second resin member based on the displacement amount of the at least of the first contact surface and the second contact surface obtained from the displacement sensor, the control unit controls the clamping unit to increase the clamping force, and
• when the control unit subsequently detects reversal of a direction of the displacement of the at least one of the first contact surface or the second contact surface based on the displacement amount of the at least one of the first contact surface or the second contact surface obtained from the displacement sensor, the control unit controls the clamping unit to decrease the clamping force.