Laser process monitoring 4D.TWO® & 4D.watcher
Detect weld seam defects during the process and reduce rework
Increase the efficiency and reliability of your laser welding processes with this new, advanced quality monitoring system. Potential errors are detected during the welding process, reducing the need for costly subsequent inspections.
Advantages of 4D.TWO® & 4D.watcher laser process monitoring
Various factors such as machines, workpieces, and environmental conditions influence the laser process. Even the smallest parameter deviations can mean that the welding of the component is no longer within the permissible tolerance range.
During each individual laser application, the interaction of the laser light with the material produces characteristic process radiation. Changes in this optical radiation indicate the progress of the process. Deviations and errors in the process are automatically transmitted to the system control via defined warning thresholds that are adapted to the individual application. Defective parts can then be sorted out and reworked if possible.
Process monitoring during the welding process is therefore an important part of quality assurance. With 4D.TWO® and 4D.watcher, you have maximum control over your laser process.
Overview of advantages:
- Sophisticated monitoring system for laser series processes, such as joining
- Provides information on the stability of a welding process
- Detects weld seam defects as they occur
- Supports the user in ensuring that components with defective welds are not further processed
- Ensures compliance with tolerated process parameters
- Process monitoring without cycle time losses
Laser welding with monitoring
In automotive production in particular, such as in the manufacture of batteries, electric motors, or safety-related components, detecting defects during production is a major advantage. Subsequent repairs to these high-quality components must be avoided wherever possible from a technical and commercial point of view, as they reduce the efficiency of the production plant. If defects are detected directly during welding, timely intervention prevents the plant from producing further defective components – in this way, predictive process monitoring is achieved.
A laser monitoring system such as 4D.TWO® & 4D.watcher detects weld seam defects as they occur. Defective battery contacts, sealing seams, or hairpin connections, for example, can be immediately re-welded or replaced. This prevents entire components from having to be rejected at the end of a production line.
Another advantage of laser process monitoring with 4D.TWO® & 4D.watcher is that the statistical evaluations of all welding positions from previous production runs help to maintain optimal process parameters.
Areas of application for laser process monitoring in laser welding
- Welding hairpins in the production of electric motors where internal defects such as pores reduce the electrical conductor cross-section.
- Welding of material combinations such as copper on aluminum, copper alloy on stainless steel, etc., where intermetallic phases can form that are potentially brittle.
- Welding of battery contacts – many joints with high demands on precision and quality to prevent cell failure or damage.
4D.TWO® is your universal multi-sensor data source for (almost) any laser application where process monitoring is crucial for quality control. It far surpasses the capabilities of other sensors in terms of precision, sensitivity, and versatility. It delivers up to 1 M samples/s based on 42+ raw channels with a wide range of physical properties – all in a compact device.
The advantages of the 4D.TWO® sensor:
- Multispectral system: Light-sensitive sensor with precise wavelength spectrum (16 channels in the visual range, 16 channels in the infrared range). In addition to these spectrally resolved channels, the 4D.TWO® has channels of the 0th order for VIS (visible light), NIR (infrared light), and retro-reflection. Together with a motion and environment sensor, this results in a total of 42+ channels for scanning.
- Process control: Process parameters are monitored in real time. In series production, quality- and productivity-related process data for the laser weld seam is systematically recorded and documented. This applies to all common laser joining processes and other laser processes.
- Lossless technology: Two integrated evaluation units prevent incomplete measurements and downtime. Lossless technology detects even very short deviations in the laser process. Events of < 40 µs can be reliably detected with a signal change (decrease or increase of 100 %) at a sampling rate of only 6 kHz.
- Extensive data collection: 4D.TWO® also measures temperature, humidity, and air pressure. Its 9-axis motion sensor enables the collection of additional data.
- Short adjustment time: Once successfully implemented in the welding system, all settings can be made in the software, minimizing the amount of adjustment work required on site.
The advantages of the 4D.watcher:
- Real-time monitoring: Based on information about process deviations, component anomalies such as cracks, pores, spatter, or damage can be detected in real time.
- Error type classification: By creating different combination channels – i. e., mathematical combinations of multiple sensor data – different error causes can be better identified and classified. This reduces unpredictable events in the process and downtime.
- Flexible implementation: Can be adapted to different machines and production lines.
- Data export: Recorded data can be exported, analyzed, and documented – traceability in the application.
- Customizable: Allows adjustments to specific applications and their monitoring requirements.
- Additional sensor data: Third-party data can be implemented for synchronized data analysis.
- Adapter modules: Enable the integration of sensor technology into a wide variety of laser processing optics from all common manufacturers.
Illustrations below: Error images of incorrect positioning on a bipolar plate
FAQs about laser monitoring systems
Why should laser welding be monitored?
The safety and quality requirements for many products are constantly increasing, and their production is becoming increasingly complex. By monitoring laser processes, defects can be detected during welding, which significantly reduces time-consuming and expensive subsequent testing and increases efficiency.
Is process monitoring a quality measurement method?
Process monitoring itself is not a quality measurement method, but rather an indicator of laser process stability. If process stability is high, high series quality will also be achieved. Process monitoring can be considered a tool that helps identify the causes of errors at an early stage.
How does the 4D.TWO® sensor work?
The 4D.TWO® sensor has three photodiodes, each with a sampling frequency of 100 kHz in the visible range, near infrared, and laser wavelength. Thanks to its patented optical design, the 4D.TWO sensor unit can also break down the emitted process light into its spectral components using two 6 kHz spectrometer units. This unique feature results in 16 channels in the visible spectrum range (approx. 350–900 nm) and 16 channels in the near-infrared range from approx. 1,100 nm to 1,700 nm.
What does lossless technology mean in laser welding?
Lossless technology allows the monitoring of high-speed processes such as the welding of bipolar plates at speeds of more than 1 m/s. Conventional sensors scan the actual value at the corresponding frequency, while the 4D.TWO® sensor determines the actual value by integrating the time between two measurements. This means that no signal peaks remain invisible, so even very short or fast processes can be reliably monitored. With lossless technology, significantly less data volume is generated due to the lower sampling rate. The 4D.TWO® sensor can detect errors in a time period of 40 µs with its 6 kHz system.
Why is it so difficult to monitor the laser welding process?
Laser process monitoring poses a major challenge for series production, because the range of permissible parameter deviations is very narrow, especially in the production of precision components. The monitoring systems implemented must therefore be able to detect even the smallest deviations at high speed. This places high demands on both the sensor system and the evaluation unit.
Why does ABICOR BINZEL sell monitoring systems from 4D Photonics?
With more than 2,000 systems installed internationally, 4D Photonics has extensive experience in laser process monitoring. Depending on the application, the laser process monitoring experts develop a concept, configure the system, and take care of commissioning and training. ABICOR BINZEL is the global service partner. Thanks to our global sales and service network, we can provide you with even more reliable and cost-effective advice and support on site.