Process Monitoring

IPG Photonics provides real-time inline weld process monitoring
solutions that can be utilized in a variety of applications including
automotive, aerospace, R&D, and additive. Utilizing inline
coherent imaging technology, the LDD product provides
up to five different geometric measurements, including
weld penetration depth, simultaneously.
Active steering of the imaging beam seeks out defects
immediately before, during, and after the welding
The combined monitoring solution only requires
a single presentation of the part, with little to no
additional cycle time, on-head bulk,
or floor space required. 

LDD-700 IPG’s new monitoring systems are the next paradigm in industrial weld quality assurance. The LDD-700 weld monitoring system uses Inline Coherent Imaging (ICI) to provide a new level of detail and accuracy for laser weld monitoring. ICI uses a low-power IR laser beam to gauge distances. This measurement beam is fired through the same optics as the welding laser, right to the bottom of the keyhole, and records its depth in real-time. The result is a direct, geometric measurement of weld penetration, acquired in-process. This data is comparable to a cut and etch of the entire length of the weld—for every weld—without destroying the part—and the results are available instantly.

                                                                                                                                                                              LDD Laser Weld Monitoring

The LDD-700 Inline Process Monitor

  • High Speed, High Resolution
  • Immune to Process Radiation
  • Gives Data Similar to Sectioning, Immediately

Capable of Detecting Defects Including

  •  Over and Under Penetration
  •  Part Misalignment: Height Variation, Gap Width
  • Weld Bead Defects: Blowouts, Underfill

Patented, Proven and Highly Productive

Inventor Dr. Paul Webster and his company Laser Depth Dynamics filed and was granted a patent in 2014 titled “Methods And Systems For Coherent Imaging and Feedback Control For Modification of Materials” – additional United States patents followed in each of 2016-2020, and a European Patent Office grant also occurred in 2020.

LDD-700 patented and proven laser monitoring technology combined with IPG laser sources and beam delivery create highly productive laser welding systems that ensure each weld meets exact manufacturing specifications.

Inline coherent imaging provides real-time dynamic beam alignment enabling measurement flexibility of the keyhole to account for deviation in process direction and variation plus environmental variability. Manufacturers are assured that every part produced meets their stringent quality standards and the expectations of their customers.

  Laser Depth Dynamics Patented Inline Weld Monitoring

Real-time AISI 8620 Welding Quality Monitoring


Butt weld - 3.2 mm deep, 2 m/min feed rate


  • IPG Multi-axis laser system with LDD-700 imaging system
  • YLS-6000 Ytterbium fiber laser used at 2.5 kW
  • FLW-50 welding head


  • Real–time verification of weld quality, depth, width, fit and centricity
  • Measurement of focus position
  • Post-weld surface bead profiling
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