Friction stir spot welder and friction stir spot welding method
A friction stir spot welder includes: a pin; a shoulder; a rotary driver; a tool driver; and circuitry that performs an operation of driving the rotary driver and the tool driver such that the pin and the shoulder press a workpiece by a first pressing force while rotating at a first rotational frequency, and after the operation, performs an operation of driving the rotary driver and the tool driver such that a tip of the shoulder in a rotating state is pressed in to a first position. The first position is a position corresponding to 46% or more of a thickness of the workpiece from a front surface of the workpiece. A press-in speed of the shoulder until the shoulder reaches the first position is a constant speed.
1. A friction stir spot welder comprising:
a pin that is columnar;
a shoulder that is cylindrical, the pin being within the shoulder;
a rotary driver that rotates the pin and the shoulder about an axis that coincides with a center axis of the pin;
a tool driver that advances and retracts the pin and the shoulder along the axis; and
circuitry, wherein:
the circuitry performs an operation (A) of driving the rotary driver and the tool driver such that the pin and the shoulder press a workpiece by a predetermined first pressing force while rotating at a preset and predetermined first rotational frequency;
after the operation (A), the circuitry performs an operation (B) of driving the rotary driver and the tool driver such that a tip of the shoulder in a rotating state is pressed in to a preset and predetermined first position;
when the shoulder presses the workpiece by the predetermined first pressing force, surface pressure of a tip surface of the shoulder is 200.71 to 254.65 MPa;
an area of the tip surface of the shoulder is set to be smaller than 43.98 mm 2 ; and
a press-in speed of the shoulder until the shoulder reaches the preset and predetermined first position is a constant speed.
2. The friction stir spot welder according to claim 1 , wherein:
the preset and predetermined first position is a position corresponding to 46% or more of a thickness of the workpiece from a front surface of the workpiece.
3. A friction stir spot welding method using:
a pin that is columnar;
a shoulder that is cylindrical, the pin being within the shoulder;
a rotary driver that rotates the pin and the shoulder about an axis that coincides with a center axis of the pin;
a tool driver that advances and retracts the pin and the shoulder along the axis; and
circuitry,
the friction stir spot welding method comprising:
performing, by the circuitry, an operation (A) of driving the rotary driver and the tool driver such that the pin and the shoulder press a workpiece by a predetermined first pressing force while rotating at a preset and predetermined first rotational frequency; and
after the operation (A), performing, by the circuitry, an operation (B) of driving the rotary driver and the tool driver such that a tip of the shoulder in a rotating state is pressed in to a preset and predetermined first position, wherein
when the shoulder presses the workpiece by the predetermined first pressing force, surface pressure of a tip surface of the shoulder is 200.71 to 254.65 MPa;
an area of the tip surface of the shoulder is set to be smaller than 43.98 mm 2 ; and
a press-in speed of the shoulder until the shoulder reaches the preset and predetermined first position is a constant speed.
4. The friction stir spot welding method according to claim 3 , wherein:
the preset and predetermined first position is a position corresponding to 46% or more of a thickness of the workpiece from a front surface of the workpiece.
5. The friction stir spot welder according to claim 1 , wherein the preset and predetermined first position is a position corresponding to 100% or less of the thickness of the workpiece from the front surface of the workpiece.
6. The friction stir spot welder according to claim 2 , wherein the preset and predetermined first position is a position corresponding to 100% or less of the thickness of the workpiece from the front surface of the workpiece.
7. The friction stir spot welding method according to claim 3 , wherein the preset and predetermined first position is a position corresponding to 100% or less of the thickness of the workpiece from the front surface of the workpiece.
8. The friction stir spot welding method according to claim 4 , wherein the preset and predetermined first position is a position corresponding to 100% or less of the thickness of the workpiece from the front surface of the workpiece.