Bonding objects together

A method of bonding a connector to a first object, comprising:

• providing the first object with a first opening, the first opening being a through opening;
• providing the connector, the connector being separate from the first object, the connector comprising a thermoplastic material;
• arranging the first object and the connector relative to one another so that the connector reaches from a proximal side through the first opening;
• using a source of mechanical vibrations to generate vibrations, and applying the vibrations and mechanical pressure to the connector until, under the effect of the vibrations and the pressure, a flow portion of the thermoplastic material is liquefied and caused to flow sideways radially into an open space;
• and
• removing the source of the vibrations and causing the liquefied thermoplastic material to re-solidify;
• wherein after the step of removing, the connector comprises a foot portion, a head portion, and a shaft portion between the foot portion and the head portion, the shaft portion extending along an axis through the first opening, and thereby securing the connector to the first object;
• wherein the flow portion forms at least a part of the foot portion or the head portion or both, the foot portion and the head portion;
• and
• wherein the following condition is fulfilled:
• the step of applying the vibrations and the pressure comprises coupling the vibrations through a proximal coupling-in face of the connector and transmitting the vibrations through the connector to a distal end face of the connector for liquefying the flow portion.