Audi TT Coupe '07 383 Assembly instructions

383
All rights reserved. Technical
specifications subject to
change without notice.
Copyright
AUDI AG
I/VK-35
Service.t[email protected]
Fax [phone]
AUDI AG
D-85045 Ingolstadt
Technical status: 05/06
Printed in Germany
A06.5S00.28.20
Audi TT Coupé ´07 - Body
Self-Study Programme 383
Vorsprung durch Technik www.audi.de Service Training

Audi-Space-Frame ASF®of the Audi TT Coupé
The development targets for the bodyshell of the Audi TT
With a weight advantage of 48 % over a comparable all-steel bodyshell, in addition to an optimised weight
distribution, the new composite aluminium-steel spaceframe body of the Audi TT marks yet another mile-
stone in the development of modern Audi bodyshells.
Crash safety of the bodyshell is enhanced by means of load-bearing structures at the front end, sides and rear
end, with a heavy emphasis on pedestrian safety.
To ensure efficient volume bodyshell production, various new joining and production techniques are
employed.
The repair concept is based heavily on the well-known aluminium repair concept. However, of course, the
materials combination of aluminium and steel necessitated that new approaches be taken.
383_001

NoteReference
The self-study programme teaches the design and function of new vehicle models,
new automotive parts or new technologies.
The self-study programme is not a repair manual!
All values given are intended as a guideline only and refer to the software version valid at the time of
preparation of the SSP.
For maintenance and repair work, always refer to the current technical literature.
Contents
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Punch riveting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Clinching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
MIG welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Resistance spot welding and MAG welding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Structural bonding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
New joining technique: solid punch riveting (Kerb-Konus riveting) . . . . . . . . . . 16
New joining technique: Flow Drill screwing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
New joining technique: aluminium laser welding . . . . . . . . . . . . . . . . . . . . . . . . . 18
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Technological concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Contact corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Combination of steel and aluminium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Comparison of ASF concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Audi Space Frame of the Audi TT
Joining techniques and production processes
Bodyshell safety concept
Repair concept
Aluminium repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Steel repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Aluminium-steel repairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Workshop equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Qualification of aluminium. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Head-on collision, side impact and rear collision . . . . . . . . . . . . . . . . . . . . . . . . . 26
Pedestrian safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Electromechanical rear spoiler

4
Dimensions
Audi Space Frame of the Audi TT
383_002
Audi TT Coupé ’ 07 2,0 3,2 quattro
Transmission Manual gearbox S tronic Manual gearbox S tronic
Kerb weight without driver in kg 1260 1280 1410 1430
Max. perm. gross weight in kg 1660 1680 1810 1830
cw (rear spoiler extended) 0.3 0.3 0.31
Boot capacity in l 290 (700*) 290 (700*)
Max. power output in kW 147 (200 bhp) 184 (250 bhp)
vmax in kph 240 250
Acceleration 0-100 kph in s 6.6 6.4 5.9 5.7
Fuel consumption in l/100 km 7.7 7.7 10.3 9.4
* with the rear-seat back folded forward

5
Technological concept
383_003
Aluminium castings
Sheet-aluminium parts
Aluminium extruded sections
Sheet-steel parts
Sheet-steel parts are used for the first time in the
ASF of the new Audi TT in addition to aluminium
castings, aluminium extruded sections and alumin-
ium sheet-metal parts. Collectively, they make up
the body structure. Vehicle weight distribution has
been optimised by using sheet-steel parts in the
rear body section. This has a direct bearing on
sporting characteristics, such as driving dynamics
and acceleration as well as safety characteristics,
such as stopping distance and driving stability
In spite of the partial use of sheet-steel parts, the
total body weight of 277 kg, including attachments
such as doors and lids, is considerably less than
that of a comparable all-steel body.
Although the new TT has grown in size, the gross
weight of the vehicle has been reduced through the
use of the aluminium-steel bodyshell.
The body structure of the new Audi TT has higher
strength and 50 % higher torsional rigidity than its
predecessor.

6
Audi Space Frame of the Audi TT
383_004
Contact corrosion
Aluminium has a passivating oxide surface layer
which protects the material underneath from corro-
sion. This is why an unpainted aluminium part nor-
mally does not corrode.
However, if there is contact between aluminium and
a metal higher up in the electrochemical series than
aluminium and if an electrolyte, such as salt water,
is present in this region, contact corrosion will
occur.
The greater the difference in potential, the greater
the contact corrosion. As aluminium is normally the
lesser noble metal, it degrades.
383_005
Contact corrosion can only be prevented by taking
measures to stop the flow of electrical current
induced by the potential difference between
the two metals. This is best achieved by painting the
surfaces. However, the risk of corrosion is high even
if a tiny amount of paint damage occurs.
In the case of the Audi TT, the following anti-corro-
sion measures have been taken:
– coating of all steel screws and fasteners such as
self-piercing rivets
– Galvanising of all sheet-metal parts (zinc and alu-
minium have a smaller potential difference than
steel and aluminium)
– Insulation by means of adhesive
– Sealing of aluminium-steel joints
Reference
For detailed information on contact corrosion,
please refer to Self-Study Programme 239 "Audi
A2 - Body" .
Schematic of contact corrosion with example
Contact corrosion

7
Joining steel and aluminium
Thermal joining processes such as MIG welding can
be ruled out because it is not possible by these
means to make a joint which has the requisite struc-
tural and dynamic strength and will not result in
contact corrosion.
383_011
Steel
Aluminium
One of the challenges for the development of the
Audi TT bodyshell was the attachment of the sheet-
steel rear-end parts to the aluminium body assem-
blies.
383_006
Aluminium-steel connections

8
Audi Space Frame of the Audi TT
This is ensured by non-thermal joining of parts
using coated self-piercing rivets and special screws
in combination with bonding.
Special requirements are made with regard to the
strength and corrosion protection of the joints
between aluminium body parts and steel parts.
Adhesive bonding is the basis for the corrosion pro-
tection of corrosion-susceptible aluminium/galva-
nised steel joints in the bodyshell of the Audi TT.In
this way, the mating materials are superficially insu-
lated, thus suppressing corrosion processes at the
point of contact. As a further measure, all compos-
ite joints either sealed with PVC or coated with wax
preservative after the cataphoretic dip coating (KTL)
process.
Aluminium and steel joints with faulty corrosion pro-
tection can exhibit much higher corrosion rates than
all-aluminium joints or all-steel joints.When making
aluminium-steel joints, therefore, highest standards
of quality must be maintained at all times during the
production process and in the service workshop.
383_012
Adhesive
Adhesive

9
The aluminium sheet shown here exhibits severe
contact corrosion, which has resulted in mechanical
failure of the punch riveted joint.
This illustration shows clearly what effects contact
corrosion can have if adequate corrosion protection
is not provided. A this joint, the flange was sealed in
the bodyshell without using adhesive.
In this case, the aluminium sheet showed no dam-
age due to contact corrosion after exposure to iden-
tical environmental conditions.
By way of a comparison, this illustration shows the
same flange with an adhesive bond and sealing.
383_007
Seal
Seal
383_008
Seal
Adhesive
Seal

10
Audi Space Frame of the Audi TT
Comparison of ASF concepts
Audi A8 (2003 ➔)
383_013
Aluminium castings
Sheet aluminium parts
Aluminium extruded sections
383_014
Sill section Audi A8
Three-chamber extruded section
383_017
A-post, Audi A8
Single-chamber extruded section

11
Audi TT (2006 ➔)
383_009
Sheet aluminium parts
Aluminium extruded sections
Sheet-steel parts
Aluminium castings
383_015
A-post, Audi TT
Sheet-aluminium sections (interior/exterior)
383_016
Sill section, Audi TT
Four-chamber extruded section

12
Joining techniques and production processes
383_018
Riveted joint
Overview
In addition to well-known processes such as MIG welding or punch riveting, the joining techniques of Flow
Drill screwing and Kerb-taper riveting are used for the first time on the Audi TT.
In the production process, a laser cleaning method is used for cleaning before the roof drip moulding is
attached by welding.
383_019
Flow-Drill screw connection
383_020
Clean Laser
Technology Process Quantity per vehicle
Mechanical
joining techniques
Punch riveting
Flow Drill screwing
Solid punch riveting (Kerb-Konus)
Clinching
1615 pce.
229 pce.
96 pce.
164 pce.
Thermal
joining techniques
MIG welding
Laser welding
Resistance spot welding
MAG welding
Stud welding
21462 mm
5309 mm
1287 spots
809 mm
234 pce.
Bonding technology Bonding 97156 mm
Machining technology Milling
Drilling
Thread cutting
Brushing
Roll seaming
Clean lasering
188 mm
16 pce.
8 pce.
2300 mm
26737 mm
4000 mm

13
Punch riveting
Punch riveting is one of the principal joining techniques used on the bodyshell of the new Audi TT. This tech-
nique is used for joining aluminium body parts and for joining aluminium body parts to steel body parts.
The process has been in use since launch of the Audi A2. Self piercing rivets with two different diameters and
lengths are used in the Audi TT.
Punch riveting process
383_051
Applications of punch riveting
With clinching, the metal sheets to be joined are clamped between a die and a blankholder. The sheets are
then pushed down into the die by a punch to form an interlocking joint. However, joints produced in this way
is not as strong as joints produced by punch riveting, for example.
In the Audi TT, this technology is used on attachments such as doors and lids. Several clinched joints are also
located in the area of the B-post and rear wheel arch. In this area, aluminium sheets as well as steel and alu-
minium sheets are clinched together.
Applications of clinching
383_053
Clinching process
Clinching
383_052
383_032

14
Joining techniques and production processes
MIG welding
The usual techniques of resistance spot welding and, to a lesser extent, metal active gas welding (MAG weld-
ing) are used for joining sheet steel body parts in steel body manufacturing.
Resistance spot welding and MAG welding
383_055
Applications of MIG welding
383_057
Applications of resistance spot welding
Applications of MAG welding
383_056
Resistance spot welding process
383_054
MIG welding process
Aluminium parts have largely been joined by means of metal inert gas welding since the launch of the Audi
aluminium bodyshell in the Audi A8 (1994) . This technique is principally used to make joints between castings
and extruded sections, as well as sheet-metal parts.
This joining technique is notable for producing high-strength joints, but it introduces a great deal of heat into
the joint and has a relatively slow process speed.

15
Structural bonding
In certain areas, adhesive bonding is used supplementary to clinched joints and punch riveted joints, solid
punch riveted joints, Flow Drill screw connections and resistance spot welds. This improves joint strength.
Adhesive bonding is also used for strengthening of seam joints, e.g. in the rear wheel arch. In other areas of
the body, adhesive beads are used for sealing and insulation between aluminium and steel sheets, as well as
for noise reduction.
Structural bonding process in production
383_058
383_059
Applications of structural adhesive

16
Joining techniques and production processes
New joining technique: solid punch riveting (Kerb-Konus riveting)
Solid punch riveting or Kerb-Konus riveting involves the use of aluminium or coated stainless steel rivets. In
contrast to punch riveting, the rivet is punched through both sheets to be joined.
Unlike steel rivets, aluminium solid punch rivets can be reworked mechanically. This is the case with the joint
between the body side section and the drip moulding. However, the strength of solid punch riveted joints is
inferior to that of punch riveted joints.
383_073
Micrograph of a solid punch riveted joint
383_060
Solid punch riveting process
383_061
Solid punch riveting process in production
383_048
Applications of solid punch riveting
Information on the repair concept
Aluminium solid punch rivets are used in the C-post drip moulding area, while coated stainless steel solid
punch rivets are used in the region of the roof frame. Stainless steel rivets must not be drilled out or ground,
due to the risk of corrosion.

17
383_062
Flow Drill screwing process
New joining technique: Flow Drill screwing
Automatic direct screwing enables joints to be made between any materials, even if these materials can be
accessed from one side only. A special coated screw is driven under high surface pressure through a hole in
the outer part to be joined. The lower part is not predrilled. The pressure and rotational speed soften the
material and allow the screw to be inserted.
383_063
Screwing process in production
Flow Drill
Screw
383_074
Micrograph of a Flow Drill screw connection
383_064
Applications of Flow Drill screwing
Information on the repair concept
Flow Drill screws can be removed in the service workshop and replaced with new screws. In case of thread
damage, screws are also available in oversize (M6 instead of M5) . For use in new parts, it may be necessary to
predrill the material.

18
Joining techniques and production processes
New joining technique: aluminium laser welding
(invisible roof seam)
Laser welding has been used for joining aluminium body parts since the launch of the Audi A2. In most cases,
sheet-metal parts are welded onto castings or extruded parts. The invisible joint in the roof area is joined
using a new joining technique: laser welding.
383_066
Laser welding process in production
383_025
Micrograph of the roof frame and roof panel joint
383_067
Applications of laser beam welding
Invisible roof seam
Applications of laser beam welding
Laser beam
Evaporating metal vapour
Welding wire
Vapour / plasma / channel
Direction of welding
Laser-induced plasma
Liquid melt zone
Solid melt zone
383_065

19
To ensure consistent laser welding of aluminium parts, the parts to be welded must have a perfectly clean sur-
face. This is achieved either by washing the component parts followed by chemical pickling or by using the
new Laser Clean process.
A controlled laser beam removes all residues from the surface by heating it for a short time. Parts cleaned
using this method can be directly laser-welded.
383_075
Micrograph of a laser-welded seam with
Laser Clean (above) and without cleaning (below)
383_069
383_068
Laser Clean process in production
The joint between the roof frame and roof panel is reworked and surface finished automatically in the produc-
tion line by means of a brushing process.
383_070
Brushing process in production
383_071
383_072
Laser weld seam before (above) and
after the brushing process (below)

20
Repair concept
383_023
Crash box
Bumper beam 1
Bumper beam Screw connections
Bumper beam 2
Aluminium repair
The repair concept for the all-aluminium body parts
is similar to that for the repair of previous Audi alu-
minium-bodied vehicles.
The front end of the vehicle is designed in such a
way that the bumper beams and bolted crash boxes
can be replaced after minor collisions up to approx.
15 kph.
If the vehicle structure is damaged, beam 1 can also
be replaced by undoing the screw connection. All fur-
ther damage to the vehicle front end can only be
repaired by welding suitable genuine parts into place.
383_024
Joint between beam 1 and beam 2