Industry Spotlight: How Automotive Manufacturers Use Inline Thermography to Secure Process Stability and Traceability

In today’s manufacturing landscape, precision and sustainability are more crucial than ever. Plastic parts joined by laser welding have long been valued for their clean, reliable, and precise connections. However, LPKF's pioneering Laser De-Welding technology takes this precision a step further—by enabling clean and efficient separation of welded plastic parts whenever needed. This capability provides manufacturers with unprecedented flexibility, cost savings, and a stronger alignment with sustainability and quality goals. 

Key Challenges in Automotive Plastic Welding 

Automotive production requires absolute process stability. But achieving it in high-speed environments isn’t easy, especially with: 

• Material variability (e.g. fillers, glass fibers, recycled content) 

• Multicavity tools introducing cavity-to-cavity variation 

• Tight design envelopes and complex weld contours 

• Short cycle times and just-in-sequence manufacturing 

Traditional quality checks (leak tests, destructive sampling) can’t keep up - and often fail to correlate with long-term durability, especially under thermal or mechanical load. 

Inline Thermography for Process Stability and Quality Assurance 

TherMoPro from LPKF is especially developed for laser welding plastics and solves these challenges by applying non-contact infrared thermography immediately after the laser welding process. This reveals: 

• Heat input distribution across complex weld paths 

• Localized overheating or underheating 

• Weld consistency across cavities and shifts 

• Early indicators of tool wear or misalignment 

TherMoPro delivers its full performance with its specialized software solution. All parameters relevant for thermal joining are analyzed and help to classify the welding quality of the part. Herefore more than 20 thermal parameters per part are automatically analyzed and logged- ensuring every part meets defined thermal quality standards before it leaves the station. 

Built for Traceability and Series Production 

Each thermal profile is matched to a unique part ID and stored - ready for: 

• Compliance audits (e.g. IATF 16949) 

• Root cause analysis in case of field returns 

• Comparison across material batches, machines, or shifts 

• Long-term process capability studies (e.g. Cp, Cpk analysis) 

By integrating directly into existing automation, TherMoPro supports: 

• High-throughput lines with minimal cycle time impact 

• Multicamera setups for full part coverage 

• Configurable detection logicevaluation for identifying non-conforming parts based on validated process parameters 

TherMoPro provides the thermal data and classification needed to enable automated sorting or rejection mechanisms - where appropriate and approved by process validation and product verification. Its flexibility allows manufacturers to tailor responses to detected NOK partsconspicuous heat distribution based on their specific quality strategy and regulatory environment. 

Practical Applications in Automotive 

TherMoPro is already in use in key automotive components, including E-mobility: 

• Electronic control unit (ECU) housings 

• Electric engines 

• ADAS and camera module enclosures 

• Lighting assemblies with plastic lenses 

• Fluid management connectors and valves 

• EV battery ventilation or sensor elements 

• Battery Cells 

These applications demand more than just "pass/fail" logic—they require thermal transparency, statistical process insight, and complete traceability. 

Laser Welding Thermography - precise and predictable 

In automotive manufacturing, process stability and traceability define success. Thermographic monitoring is already state-of-the-art in metal welding – Now that LPKF have managed to develop the process so valid that it will also become state-of-the-art for plastic welding. Because with TherMoPro, manufacturers achieve both - inline, in real time, and at scale.