| 摘要 |
A joint is produced in at least two overlapping workpieces (W1, W2) using a joining tool (10) comprising a punch (16) reciprocally disposed in a cylinder. The workpieces (W1, W2) are disposed between the tool (10) and a die (12) and the tool (10) is used to apply a compressive force to deform the workpieces (W1, W2) into a joint at a joining area between the tool and the die. Continuous ultrasonic energy is applied to at least one of the workpieces in the joining area for at least part of the time during production of the joint so as to increase the ductility of at least one of the workpieces in the joining area. This induces an acousto-plastic effect in the material being formed which temporarily reduces its strength so as to exhibit increased ductility. The joining method may be used in self-piercing riveting and clinching techniques and enables viable joints to be formed in high strength materials or thick sheets of material. |
