Laser beam measurement for the automotive industry
Monday, November 23, 2020
Laser power measurements have long been a mainstay in research, medical and manufacturing applications. However, now, more than ever, laser power measurement instruments are making their way into automobile manufacturing.
The automotive industry has long been known for its reliance on accuracy, precision, and craftsmanship quality. Today’s automobiles must be manufactured to very stringent safety standards and specifications. The slightest manufacturing error on the assembly line can translate to catastrophic real-world consequences.
As such, manufacturers are demanding more accuracy and repeatability from their laser tools on the manufacturing floor.
Automobile manufacturing has evolved significantly over the decades. Gone are the days when workers would manually weld and assemble automobile parts. The growth in automation has led to increased use of automated laser welding systems on assembly lines. This growth has also led to an increased demand for reliable laser power meters.
While laser monitoring equipment currently exists, they possess several shortcomings that make them unsuitable as a measurement solution for assessing beam stability. For instance, some monitoring solutions do not measure the beam’s power output at the working point, i.e., the point where the beam interacts with the material.
Since critical failures can occur anywhere along the laser beam path, current monitoring systems cannot be considered an adequate global solution.
Laser power meters, on the other hand, are capable of measuring the power output level of your laser beam at the working point. This means that measurements are taken at the material interface, thus giving a better indication of work quality. These working point measurements give laser power detectors an inherent advantage over existing monitoring systems.
Laser power monitors are ideal for periodically monitoring and controlling the quality of the output power of welding lasers in automotive manufacturing. For example, laser power detectors can be used in conjunction with alarms in a feedback control loop system to stop welding operations if a laser delivers power outside the safe or anticipated range.
When used in this way, laser power detectors can send signals that can pause assembly lines, preventing the manufacture of defective units, reducing material wastage and minimizing manufacturer losses.
French multinational automobile manufacturer, PSA Group, has integrated laser power measurement devices into each of their 100 welding systems. To prevent dust and other contaminants from reaching the optics, the detectors are placed in protective enclosures. At the PSA facility, each automated laser tool is programmed to periodically stop, aim at the detector and expose it to the beam for approximately 30 seconds.
If the measurement from the detector is within PSA prescribed limits, it is considered to be acceptable, and the laser returns to work. However, if the laser’s output exceeds tolerances, a signal is sent to a controller and the assembly line is stopped.
This real-time measurement process allows operators to quickly diagnose the root cause of laser anomalies and prevent catastrophic manufacturing errors.
Unlike conventional thermal power detectors, which analyze the output of a thermopile disk, Gentec-EO’s HP-series of power detectors work by measuring both the flow rate and temperature of water moving through a cooling circuit in a thermal mass.
When the laser hits the detector's absorber, the absorbed heat is transferred to the cooling water in the cooling circuit. This heat is then dissipated from the water as it flows through the circuit. The flow rate and the temperature difference at the entrance and exit ports of the cooling circuit are measured and used to determine the optical input laser power.
The calorimetric nature of this type of technology allows our power detectors to provide reliable and repeatable results for power levels ranging from a few hundred watts up to more than 100kW with custom models.
In addition, the built-in thermometer and flowmeter give our detectors a ‘smart’ feature, allowing them to detect inappropriate cooling-water parameters. This feature is critical for setting alarms in feedback control loop systems.
Gentec-EO has over 45 years’ experience manufacturing and supplying power detectors for many industrial sectors, including the automotive industry. We are known for providing our customers with some of the most reliable and accurate laser beam measurement devices on the market.
If you are in the automotive industry, you know that there is little to no margin for error. With Gentec-EO’s line of detectors, you can rest assured that your laser power measurements will be accurate and obtained with excellent repeatability, an absolute must for sensitive automobile manufacturing operations.
This feature, in addition to their robustness and overall quality, make our HP power detectors a proven asset in both existing in-process and post-process monitoring systems.