Process Monitoring Examples for Laser Welding and Cleaning
Following are some examples of manifold process monitoring applications.
The joining of copper connections is a primary production step of the electric motor. Modern electric drives are “wound” with rectangular wires instead of round wires. Each of these 100 to 200 hairpin pairs must always maintain electrical conductivity over its service life. If a connection fails, the motor will no longer work. In cooperation with the Institute for Beam Tools in Stuttgart, we have analyzed in complex series of tests how and with what benefits the WeldWatcher could be used for automatic monitoring during welding.
Ejections can occur, in particular, due to contamination and paint adherence. In this case, shown here, the ejection at the end of the weld is no longer visible; the seam is from outside “OK”. A look at the computed tomography result shows that there are large imperfections and many small bubbles inside. With the WeldWatcher®, it is visible that the seam is not OK already during the welding process. In this way, time-consuming and costly tests such as CT or micrographs can be saved.
Copper Hairpin Welding 4 mm x 2 mm
Laser cleaning is often used to prepare the housings of prismatic cells. By doing so, organic residues of release agents are removed from the later joint in advance. Impurities can cause seam defects in the later weld seam, which can lead to leaks.
Integration into the Laser.
Welding CuSn6/1.4301 – Spatter Detection
Welding with visible laser radiation (blue): Certain seam defects regarding joining connections of different types can also be detected during the welding process. The following example shows a connection between a copper alloy and stainless steel. In this case, contamination resulted in an ejection. The WeldWatcher detected this ejection reliably.
Laserline LDM blue 1000-40
IPG Single Mode 1000 W
Fraunhofer ILT Welding Head
P = 950 W @450nm
P = 950 W @1070nm
v = 100 mm / s
Combi Sensor (dual)
Integration in processing scanner
When joining materials of different types such as aluminum with copper, good process management is extraordinarily essential. If the two materials mix too much, intermetallic phases are formed that are brittle and undesirable. If the welding depth is too low, the connection cross-section is no longer sufficient to achieve the desired tensile strength.
In this application example, we found an approach to determine the mixing of the materials during welding indirectly. The picture shows the top view of the seam. It can be seen that the underlying curve of our signal correlates with the aluminum content on the top of the weld seam.
HighYag HighMotion 2D
Integration in the beam switch (monitoring of all outlets)
Cu 0,3 mm auf Al 1,0 mm
18 m / min
In Cooperation with:
Laser bonding is increasingly used for connections in battery technology and power electronics. A flat wire is placed on the component and welded at two points with spot or linear seams. The remarkable thing is the low heat input. Also, short welding times are achievable. For the bonding of a sensitive component, the ceramic of the PCB must not be destroyed. In cooperation with Fraunhofer ILT, we have evaluated the possibilities of defect detection during such a bonding process.
SPI Single Mode 1 kW
ILT / F&K Delvotec
1 kW @100 mm / s
2 mm x 0,25 mm Copper
Seam length 1 mm
Combi Head (dual)
integrated into processing head
As power increases, process radiation increases too. This observation is due to higher thermal radiation. At 68% of the laser power, there is an ejection at the beginning of the second half of the seam, as the laser radiation reaches and destroys the ceramic base material. Thus, in this application, the system can be used to prevent welding into the ceramic material reliably during production. Also, the WeldWatcher is a valuable aid for prevention, as the laser power can be set explicitly to stable process parameters.
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With more than 1400 systems installed worldwide, we have a lot of experience in all sorts of laser processes. Simply contact our experts to review your requirements and discuss solutions that are right for your application. We would be happy to visit your location in order to better understand your process and determine how our solutions might meet your expectations.