Full Digital Welding Power Source
Presented by Thomas Augustin
on behalf of
Lorch Schweisstechnik GmbH
Auenwald / Germany
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
A quick introduction of Lorch
•Lorch is the biggest German welding manufacturer,
located in the south of Germany , near Stuttgart
•Lorch has 140 employees , about 20 R&D engineers
•Annually production of nearly 20 thousand welding units
•One of the technology leaders of the whole welding branch
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
Today‘s topics
•Past (& present ) situation
•User demands
•Analogue and digital
•What is a digital welding power source
•Advantages of a digital welding power source
•The benefits for the operator
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
Past ( & present ) situation
Block diagram of a conventional transformer
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
Past ( & present ) situation
•Today still the most manufacturers stick with conventional
technology
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
Past ( & present ) situation
Block diagram of an inverter
Primary Rectifier
Digitally
controlled
© Lorch Schweisstechnik GmbH, Jahr 2006
Transistor ( MOS FET/ IGBT)
Transformer
Analogy
controlled
Secondary Rectifier
Inductor coil
Full Digital Welding Power Source
Disadvantages of analogue technology inside of a welding machine
•Most of the analogue machines are difficult to operate
•Sensitive for input voltage fluctuation
different input = different output
•The machines, even from the same range, vary in
performance due to scattering ( tolerances in parts and
production )
•Time consuming in maintenance , PCB‘s have to be trimmed
•Machines have to be calibrated frequently
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
User demands
•Highest demand on welding performance and quality
•100 % repeatability
•Easy to operate
•Synergic adjustment - one knob use
•Prevention of faulty operation
•Easy service
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
What is digital
•You might still remember the times when music was played
from a LP record
•The more often it was used the quality declined until there
was only scratchy noise left
•That has completely changed when the CD was introduced
•On a CD the music is stored digitally, no matter how often it is
played, the sound is the same
•100 % repeatability no matter how often it is played
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
Transferred to a welding power sources
•The welding process is stored digitally on the DSP
( Digital Signal Processor )
•That means the arc itself is specified by software ;
rather than by inflexible hardware
•Functions and characteristics of the welding machine
are no longer sensitive for ageing and wear out
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
What is a digital power source
User panel
Flow meter
Solenoid valve
HF-protection
DSP
EMV-Filter
HF-ignition
Master Process Control
Snubber circuit
Robot-interface
(The brain)
Communication to user panel + power source
Bus ( Lorch Net )
Primary Control
-Inverter (80 kHz)
-MOSFET Transistors
© Lorch Schweisstechnik GmbH, Jahr 2006
Alternator with IGBT
-compact modules
-Controlled by MAPRO
-Stable polarity reversal
Power UP
Inrush current
limitation
Full Digital Welding Power Source
The functional principle
µProcessor
receives actual
value of current
and voltage
Welding current
and voltages is
changed
µProcessor gives
command to
power source
© Lorch Schweisstechnik GmbH, Jahr 2006
µProcessor
compares actual
and desired value
µProcessor
calculates reaction
to cancel deviation
Full Digital Welding Power Source
The components , for example a 300 Amp ACDC TIG unit
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
The Software Tool
•Enables to preset perfect parameters for all wire/gas
combinations ( MIG Pulse )
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
Possible pulse shape of a digital Pulse MIG
Power source
e.g. 3 stage pulse with slopes
Ip2
Ian_in
IS
Iab_in
Ip1
Ig Ian
Ip3
t
tp3
tp2
tp1
© Lorch Schweisstechnik GmbH, Jahr 2006
Iab
Tp
Full Digital Welding Power Source
The advantages of a digital power source
•100% repeatability
•Insensitive for input voltage fluctuation
•Insensitive for temperature thrift
•Less electronic components required
•Insensitive for ageing
•Easy maintenance due to plug and play PCB‘s ,
no trimming necessary
•High flexibility , customised functions can be achieved by
software without changing hardware
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
The advantages of a digital power source
•Due to communication via Bus System (LorchNet™)
no interferences
LorchNet™
Hot plug and play , during
welding possible.
System automatically
recognises change .
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
The benefits for the operator
•Easiest setting due to synergic function= one knob use
•Full synergic operation = the operator just recalls the
parameters which are stored in the database, according to
the present task
•Special synergic lines for uncommon
materials can be uploaded , customised for
individual requirements
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
The benefits for the operator
•User is guided by text display , invalid
adjustments create an Error message to avoid
faulty operation
•Job memory to store settings for frequently
tasks. Recallable from the torch during welding.
•Special functions can be uploaded by software
© Lorch Schweisstechnik GmbH, Jahr 2006
Full Digital Welding Power Source
The benefits for the operator in results
Compensation of welder inconsistence
Compensation of work piece inconsistence
MIG Pulse with TIG like appearance due to
TwinPulse™ technology
© Lorch Schweisstechnik GmbH, Jahr 2006