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Real-Time Weld Measurement

Real-Time Weld Measurement

Part Conformity

Part Conformity

Accurately measure every laser weld in real time and only ship parts that meet specifications.

Minimized Cost-Per-Part


Decrease scrap and rework and eliminate time-consuming and destructive weld testing.

Maximize Traceability


Track and record critical key weld metrics and integrate with manufacturing systems.

What is Real-Time Laser Weld Measurement?

Real-time laser weld measurement directly measures 20+ weld metrics before, during, and after the welding process. This innovative solution provides unmatched in-process Quality Assurance (QA) to enable manufacturers to weld faster, more cost-effectively, and with unmatched confidence.


Despite the stability and repeatability of laser welding, unexpected material properties can result in imperfect welds. Traditional weld QA often involves time consuming post process steps like resistance testing or destructive cross sectioning that provide incomplete data.

Direct Measurement of Key Weld Metrics

Weld Depth Measurement

Weld Depth

Direct weld depth measurement ensures under- or over-penetration does not compromise joint strength or electrical performance.

Seam Position

Seam Position

Scanning ahead of the weld to confirm part alignment and weld path enables automatic seam realignment if necessary.

Transverse Profile

Transverse Profile

Measuring the weld seam's bead width and shape detects overfill, underfill, or edge undercut that can indicate a weak finished joint.

Finished Surface

Finished Surface

Analyzing the finished weld surface checks for defects that may indicate reduced structural integrity or increased electrical resistance.

Photodiode Measurement vs. Real-Time Measurement

Alternative in-process laser weld measurement technologies like photodiode rely on indirect measurement of weld quality indicators like weld plume, back reflection, and heat-affected zone. These imprecise process characteristics provide unreliable correlations with weld quality and must be calibrated on a per-process basis. Since pass/fail parameters are based on indirect data, confidence in final part quality requires unnecessarily aggressive failure conditions that result in a high rate of false failure and part scrap or rework.

By comparison, LDD real-time weld measurement provides direct, distance-based measurements of critical geometries like weld depth. LDD technology does not rely on in-process indicators and offers direct monitoring of pre-weld, in-weld, and post-weld measurements in parallel. Micron-scale precision on direct weld quality measurements enables significantly tighter QA tolerances that dramatically reduce false failures.


  • Technology

  • Measurement & Validation

  • Measurement Accuracy

  • False Failures

  • Process Flexibility

Photodiode Weld Monitoring

  • TechnologyPhotodiode Sensors

  • Measurement & ValidationIndirect Measurement

  • Measurement AccuracyModerate

  • False FailuresHigh

  • Process FlexibilityRequires Process-Specific Calibration

LDD Real-Time Weld Measurement

  • TechnologyInterferometric Ranging

  • Measurement & ValidationDirect, Geometric Measurement

  • Measurement AccuracyHigh

  • False FailuresVirtually None

  • Process FlexibilityNo Calibration Required

Weld Verification — The IPG Difference

Weld Verification — The IPG Difference

Unlike most weld monitoring techniques that simply monitor imperfect weld quality indicators like weld plume, LDD performs direct weld penetration measurements and 3D imaging to see exactly what the welding beam sees.

Compared to alternative technologies, LDD provides:

  • Full penetration weld depth measurement & quality assurance
  • Compatibility with single-mode laser welding
  • 3D imaging of keyhole and live 3D viewing for robot teaching
  • Keyhole alignment in any direction
  • Compatibility with high-speed on-the-fly welding
Laser Weld Measurement for Industry 4.0

Laser Weld Measurement for Industry 4.0 Webinar

In this on-demand webinar, learn how direct in-process weld measurement can help you reduce scrap and identify defects earlier to save time and reduce operating costs.

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Ready to Learn More About Real-Time Weld Measurement?

Whether you have a project in mind or just want to learn more about IPG real-time weld measurement technology, a laser expert is ready to help.