„DeltaSpot“ A new spot welding process

„DeltaSpot“
A new spot welding process
DI (FH) Martin Eiersebner
Fronius International GmbH
DeltaSpot Resistance Welding
Buxbaumstraße 2
4600 Wels, Austria
Tel.:+43 7242 241-3975
E-Mail:[email protected]
„DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Principle of resistance welding
The workpieces are pressed together using electrodes and a welding
current is briefly applied.
The required heat is generated by the electrical resistance of the
welding zone.
This heating takes place according to Joule's law:
Q = I2 * R * t
Q ... quantity of heat (Ws)
I ..... welding current (A)
R .... combined resistance (Ohm)
t ..... welding time (s)
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Factors of influence on the resistance
Electrode force:
Electrode soiling:
Small electrode force – high contact resistance
Large electrode force – small contact resistance
Clean electrode – small contact resistance
Soiled – high contact resistance
Chronological resitance sequence:
During the welding time, the contact resistence loses it`s
importance and the material resistance increase.
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Definitions
Weld nugget
HAZ
Base metal
Weld nugget
Lens-shaped join where the materials have melted together
HAZ (Heat Affected Zone)
Area of hard (not melted) base metal that has undergone changes in
thermal structure due to the energy inserted by spot welding.
Base metal
Material to be welded
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Conventional resistance spot welding
Most widely used joining process on automotive
assembly lines
Low-cost
Low cycle time
Robust
Simple clamping devices
However:
There are also a few problems!
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Negative factors in resistance welding
Shunting
Electrode
wear
Variation
of sheets
Variation of
mainvoltage
Edge welding
Variation of
coatings
Bad fit up
Material mix
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Innovation - DeltaSpot
100% repeatable by using
a process tape.
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Basic idea - the process tape
After one or more spots, the process tape will be
transport forward. Following this DeltaSpot has an
ideal contact situation.
Process stabilization
During the ideal contact situation between
electrode and base material we got a good
repeatability and no surface spatter.
Base material can not alloy on the Electrode
High durability
Possibility to regulate the heat in the welding zone .
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Process tape as process stabiliser
Ideal contact transfer
Conventional resistance welding
Surface spatter because of to
unevenness in the material
DeltaSpot: The tape coating is very
soft compared to electrodes
Ideal contact transfer conditions
established
No surface spatter
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Process tape as process stabiliser
Protects the electrodes from soiling
Dirt sticks to the tape and not to the
electrode
Every weld is subject to the same
conditions
Electrode life is significantly increased
Electrode service life test:
Aluminium: 2 x 1mm AlMg3 min. 15 000
spots
Steel: 2 x 1mm DC01 ZE25/25 (galvanized)
min. 25 000 spots
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Process tape as process stabiliser
Control of heat balance (weld point)
Process tape
high
resistance
Conventional resistance welding:
Large differences in resistance make it
impossible to form a weld point across
all three sheets
DeltaSpot: Weld point formation can be
controlled using different process tapes
All sheets are welded together properly
Additional heat insertion
R = very low
R = high
R = very high
Process tape
low
resistance
R..............material resistance
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Reduce the negative factors by the
resistance welding process
Shunt
Electrode
wear
Variation
of sheets
Variation of
mainvoltage
Edge welding
Variation of
coatings
Bad fitting
Materialmix
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
DeltaSpot – technical data
System description
230V/16A holder control mains connection
Standard overhang 500mm (X-holder)
Electrode force 5kN
Holder weight 100 kg
Tape reel 70m
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Main drive
System description
Lower weight
Low-cost, high-performance drive
(250 W motor for 10 KN force)
Modular design
Short installation/dismantling times
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Tape magazine - tape drive
System description
Tape cover
Tape magazine
Tape drive
Guide rollers
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
User interface
System description
Modern, intuitive and user-friendly design of the user interface
Uniform, familiar environment due to integration into Fronius-Xplorer
Touchscreen buttons and displays
Enables central access to all machines in the network from one location
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
DeltaSpot at work
Steel
- 2 and more sheet combinations with all popular coated and uncoated steels.
- welding of different material combinations and different thickness (Usibor, CrNi,...).
Aluminium
- 2 and more sheet combinations with
all popular aluminum alloys.
Steel und Aluminium
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Heat balance simulation in case of
Aluminium
Same welding parameters: force, current, time
Increasing efficiency
With tape
Without tape
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Simulation 3-sheet joint of Aluminium
3-sheet combination AlMg3
Material: AlMg3 1mm / 2mm / 3mm
Parameter: 8kA 500ms 4kN
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Heat balance simulation in case of Steel
Same welding parameters: Force, Current, Time
Increasing efficiency
With tape
Without tape
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Simulation 3-sheet joint of Steel
Material:
Parameter:
DC04 0,75mm / Trip800 1,2mm / H400 1mm
8,6kA 400ms 4kN
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Steel – Aluminium joining
Regulated heat applied to the welding zone by using different
process tapes
Possibility for controlled heating of steel and aluminium
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Results of steel-aluminium joints
Jank N.;Widerstandspunktschweißen von Stahl mit Aluminium; Doctoral Thesis in the works, Vienna University of Technology 2006
Serie 6
AlMg3 (1mm) / DC 01+ZE25/25 (1mm)
Serie 7
AlMg3 (1mm) / DC 01 (1mm)
thickness of the intermetallic compound
is under 4µm
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Quality assurance system: Q-Master
Non destructive testing
100% testing possible
Fingerprint
Documantation
of all welded joints
Low testing costs
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Quality control of spot weld joints
Non-destructive testing Ultrasonic
Disadvantages:
Only random samples can be
tested.
Major inspection effort.
Tester must be highly skilled.
Probe placed by hand.
Tester decides whether join is
OK or not, depending on his/her
level of experience.
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Quality control of spot weld joints
Destructive testing
Chisel test
(destructive, semi-destructive)
Peel test
Roll-off test
Disadvantages: Component is
destroyed, only random
samples can be tested. Major
inspection effort.
Currently the most frequently used form of quality control.
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
DeltaSpot Q- MASTER
Function
Imprint
Quality assurance based on
Image Processing.
Correlation between imprint
and nugget size.
Imprint on processtape
acquired by a camera.
Image processing software
computes nugget diameter.
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Q-MASTER basic principle
Weld core
Tape impression
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Q-MASTER basic principle
Weld core
Tape impression
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Q-MASTER basic principle
Weld core
Tape impression
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Q-MASTER basic principle
Weld core
Tape impression
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
DeltaSpot Q- MASTER
Function
Q-Master recognizes if imprint
passes centerline.
Takes image and computes nugget
size.
Time: ca. 300ms
Video in slow motion, normally 50
images/sec.
Slow motion
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Diameter avg
Correlation between Q-MASTER and
Chisel- Test at AlMgSi
Spot Nr.
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Customer status, at 20.04.07
Projekt
Testing System
Testing System
Testing System
Spyker
Testing System
Metrodoors
Customer
AUDI
VW
Benteler
Karmann
DaimlerChrysler
Bach
City
Neckarsulm
Wolfsburg
Paderborn
Osnabrück
Sindelfingen
Application
Aluminium A8 original parts
Steel
Crashbox (Aluminium) + Steel
New Modell (Aluminium)
Steel and Aluminium
Aluminium
Tong
X 500
X 500
X 500 Schwanenhals
X 500
X 500
X 500
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Frost & Sullivan - Award 2006, for the
welding technology of the year
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007
Thanks for your attention!
Are there any questions?
„ DeltaSpot“ – A new spot welding process
@ Fronius 03/2007