TPT January 2016

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Technology News
60 January 2016
Seam tracking and quality control
during laser welding
NUMEROUS trends are dictating the use
of the laser in automotive engineering.
The use of high-strength steels, weight-
saving aluminium alloys, innovative joint
geometries and unusual material mixes
has the overarching aim of making
the vehicles safer, more cost effective
and more energy efficient. Process
monitoring systems play a key role here.
At the Laser World of Photonics
trade fair in Munich, Precitec presented
the YW52 laser welding head with
integrated ScanTracker for the controlled
weld position and weld seam width.
In conjunction with the WeldMaster
system for realtime process control
and quality monitoring, this is a flexible
and comprehensive solution for difficult
welding tasks under changing conditions.
The WeldMaster measures the
joining position laterally and the width
of the gap. Instead of an external axis,
the integrated scanner mirror of the
ScanTracker precisely controls the
focal position along the measured joint.
Additionally, the mechanically controlled
collimation lens corrects any change in
the standoff distance. If, for example, the
gap width or height changes as well as
the position of the joint, the WeldMaster
system, in addition to the scanner mirror,
can overlay a high-frequency pendulum
motion and thus increase the seamwidth.
The WeldMaster also controls the laser
power, which is freely programmable,
in sync with the pendulum motion. This
makes ScanTracker the ideal solution
for applications involving differing weld
seams or extensive retooling. The seam
width is freely adjustable via an analogue
interface and requires no additional
control. A synchronous laser power
control is available to avoid intensity
peaks at the reversal points, and this can
be achieved through the freely selectable
performance profile.
The minimum lead times for the
measurement, less than tenths of a
second, and the adapted lateral and
longitudinal distribution of the linear
energy leave nothing to be desired when
it comes to optimal process control.
The WeldMaster systems for
realtime process control and quality
monitoring of laser seams are based
on one standardised platform, which
is responsible for data processing and
operator guidance. Camera systems
and sensors for measuring and
controlling the laser joining process can
be connected and evaluated to suit the
application concerned. The operator
concept is always the same, no matter
whether the system is supposed to
detect and control the joining position,
whether an image is evaluated for
detecting welding seam errors or
whether only a simple sensor signal,
the laser power for instance, is to be
depicted.
Precitec KG – Germany
Fax: +49 7225 684 900
Website:
Pipe fusion for large-diameter pipe
THE release of the TracStar® 1200 brings
the largest pipe fusion capability to date
in McElroy’s line of self-propelled, track-
mounted fusion machines.
The TracStar 1200 has many of the
same benefits as the smaller models,
but with some major upgrades. It
features an advanced emission control
engine that burns ultra-low-sulphur
diesel to meet the EPA’s latest Tier 4
standards. The cowling has also been
redesigned so that technicians have
better and quicker access to the engine
for maintenance.
“The TracStar line
was quickly embraced
when it was launched
18 years ago and its
design continues to
improve based on the
input we receive from
the field,” said the
company’s president,
Chip McElroy.
“The ability to
propel the machine
from joint to joint has
always been a major
selling point and this
feature will help meet
the growing demand for fusing large-
diameter pipe.”
The TracStar 1200 butt fuses pipe
from 450 to 1,200mm OD (16" to 48"),
and can traverse almost any terrain,
including mud, loose soil, snow and
gradients up to 30 per cent. It is self-
contained with an on-board generator
for powering the hydraulic pivoting
heater and facer.
The three- or four-jaw convertible
carriage is easily removable for in-ditch
use.
Other new features include hydraulic
outriggers for machine stability and
levelling, an ergonomic operator
platform and remote engine stop/start
capabilities.
McElroy – USA
Fax: +1 918 831 9256
Email:
Website:
The TracStar 1200
from McElroy
The WeldMaster