13
"Cold" joining technique in the Audi TT
Punch riveting
Punch welding is a method where pieces that have not been
pre-punched are joined together by inserting a rivet
(semi-tubular rivet or solid punch rivet) into two or more
layers of the workpiece, the rivet piercing the upper work-
piece layers and then expanding in the lower workpiece
layer.
Advantages:
• No pre-punching needed.
• High dynamic strength.
• Form-tting and non-positive connection.
• Ideal for hybrid joining.
Clinching
With clinching, panels or sections are joined together by
cold-forming the materials to produce a form-tting and
non-positive connection without the need for an auxiliary
joining element such as a rivet. In this case, the connec-
tions can have two or more layers.
Advantages:
• No additional connecting element.
• Protects the surfaces of coated workpieces.
Flow-drill screwing
A special, coated screw is inserted through partially non-
pre-punched workpieces by applying high contact pressure.
Due to the high pressure and high RPM, the screw forms a
thermoî›–ow hole without producing a burr. The screw
penetrates the material and, in the process, cuts its own
thread.
Advantages:
• High strength through thermo-ow process.
• Ideal for applications in which the material is accessi-
ble on one side only.
• Easy to disconnect.
Bonding
In addition to punch riveting, clinching, solid punch rivet-
ing, î›–ow-drill screwing and resistance spot welding, addi-
tional adhesive bonds are used in certain areas. These
bonds increase the strength of the connection. Adhesive is
also used in seamed connections, as is the case at the rear
wheel arch. In other areas of the bodyshell, use is made of
adhesive beads to provide sealing and insulation between
aluminum and steel, as well as for noise reduction.
Advantages:
• Large area connections are possible.
• Unchanged surface and micro-structure.
• Suitable for connecting dierent materials.
• Sealing connection.
630_061
630_063
630_064
630_078
Semi-tubular punch rivet
Solid punch rivet
630_062
To Next Page
Loading...
