A method includes a rotation locking step during which the rotation of the threaded hub about the central axis is blocked by heating a portion of the plug to soften, then by forcing the softened thermoplastic material to penetrate into, and then solidify in, a female cavity hollowed in the wall of the orifice to constitute a male member which fits into the female cavity. The female cavity forms, against the action of the male member, a guiding end stop preventing the male member, and therefore the hub, from rotating about the central axis to oppose any rotary screwing/unscrewing of the plug and maintaining a degree of freedom in axial translation along the central axis of the male member within the female cavity, so as not to impede a sliding of the hub and of its screw thread along the central axis against the wall.

A filter element (20) includes individual components (2, 4, 8), such as a filter medium (8) as one component and further filter element components (2, 4), of which at least one component (4) is made of a material that is at least partially transparent to laser light and at least one further component (2), in the manner of a barrier layer, is made of a material that is at least partially opaque to laser light to perform a transmission welding method by laser light for connecting associable components to each other. At least some of the components of the filter element that are exposed to the laser light during the transmission welding method are at least partially electrically conductive.

A filter element (20) includes individual components (2, 4, 8), such as a filter medium (8) as one component and further filter element components (2, 4), of which at least one component (4) is made of a material that is at least partially transparent to laser light and at least one further component (2), in the manner of a barrier layer, is made of a material that is at least partially opaque to laser light to perform a transmission welding method by laser light for connecting associable components to each other. At least some of the components of the filter element that are exposed to the laser light during the transmission welding method are at least partially electrically conductive.

A method of bonding a second object to a first object includes: providing the first object having a thermoplastic liquefiable material in a solid state; providing the second object having a surface portion that has a coupling structure with an undercut, so that the second object is capable of making a positive-fit connection with the first object; pressing the second object against the first object with a tool that is in physical contact with a coupling-in structure of the second object while mechanical vibrations are coupled into the tool; continuing to press and couple vibrations into the tool until a flow portion of the thermoplastic material of the first object is liquefied and flows into the coupling structures of the second object; and letting the thermoplastic material re-solidify to yield a positive-fit connection between the first and second objects by the re-solidified flow portion interpenetrating the coupling structures.

A method of bonding a second object to a first object includes: providing the first object having a thermoplastic liquefiable material in a solid state; providing the second object having a surface portion that has a coupling structure with an undercut, so that the second object is capable of making a positive-fit connection with the first object; pressing the second object against the first object with a tool that is in physical contact with a coupling-in structure of the second object while mechanical vibrations are coupled into the tool; continuing to press and couple vibrations into the tool until a flow portion of the thermoplastic material of the first object is liquefied and flows into the coupling structures of the second object; and letting the thermoplastic material re-solidify to yield a positive-fit connection between the first and second objects by the re-solidified flow portion interpenetrating the coupling structures.

The method of metal-thermoplastic resin direct bonding is characterized by comprising a first step for irradiating a surface of the metal material with a pulse laser under an oxidizing atmosphere to form a surface modification region, a second step for causing the thermoplastic resin material to abut against the surface modification region to form a bonding interface, and a third step for heating up the bonding interface by laser irradiation to achieve bonding, the first step including forming metal oxide particle clusters obtained when metal oxide particles having a particle diameter of 5-500 nm to be continuously bonded at the surface modification region, so that the maximum height (Sz) of a surface of the metal oxide particle clusters is 50 nm-3 .Math.m.

The method of metal-thermoplastic resin direct bonding is characterized by comprising a first step for irradiating a surface of the metal material with a pulse laser under an oxidizing atmosphere to form a surface modification region, a second step for causing the thermoplastic resin material to abut against the surface modification region to form a bonding interface, and a third step for heating up the bonding interface by laser irradiation to achieve bonding, the first step including forming metal oxide particle clusters obtained when metal oxide particles having a particle diameter of 5-500 nm to be continuously bonded at the surface modification region, so that the maximum height (Sz) of a surface of the metal oxide particle clusters is 50 nm-3 .Math.m.

A first object is anchored in a second object. The first object has a material with thermoplastic properties, and the second material has a material that is solid and is penetrable by the first material when in a liquefied state. The second object has an insertion face with an opening having a mouth in the insertion face, and the first object has an insert portion that for anchoring is placed in the opening or about the mouth thereof. For anchoring, energy suitable for liquefaction of the first material impinges in an amount and for a time sufficient for at least partial liquefaction of the first material and interpenetration of the first and second materials. The second object, around the opening, has an anisotropic strength with respect to forces perpendicular to the opening axis.

A first object is anchored in a second object. The first object has a material with thermoplastic properties, and the second material has a material that is solid and is penetrable by the first material when in a liquefied state. The second object has an insertion face with an opening having a mouth in the insertion face, and the first object has an insert portion that for anchoring is placed in the opening or about the mouth thereof. For anchoring, energy suitable for liquefaction of the first material impinges in an amount and for a time sufficient for at least partial liquefaction of the first material and interpenetration of the first and second materials. The second object, around the opening, has an anisotropic strength with respect to forces perpendicular to the opening axis.

A joining element has an anchoring portion for in-depth anchoring in the object and a head portion arranged proximally of the anchoring portion with respect to an insertion axis. The head portion has a lateral outer surface that has a structure that is well-defined, especially within tight tolerances. The joining element is positioned relative to an object of a non-liquefiable material such that the anchoring portion reaches into an opening of the object or is placed adjacent a mouth thereof. Then, the joining element is pressed towards a distal direction, to press the anchoring portion into the opening, while mechanical vibration energy is coupled into the joining element by a tool, in an amount and for a time sufficient for liquefaction of a portion of the thermoplastic material to cause interpenetration of the thermoplastic material into structures of the object.