How the System Works

The TPS measures the infrared intensity of radiation of the cross-section of the welded seam during solidification with a digital frequency range from 16 bits on 22 channels with a frequency of 100 to 400 Hz. This allows welding speeds of up to 180m/min. As a result, irregularities can be recognized of dimension less than 1 mm in the thermal signature. The sensitivity of the TPS can be adjusted over an area of 8 steps. In this case temperature ranges from approx. 750 °C to about 1400 °C are possible.

From the recorded thermal data the welded seam’s basic parameter will be calculated. The threshold is freely adjustably and therefore adaptable to the respective process. The basic parameters are:

• Seam position
• Seam width
• Symmetry of the thermal field
• Minimum, maximum temperature and distribution

For weld inspection purposes, the characteristic of the HAZ temperature field depends directly on the weld seam quality. Therefore unacceptable seam irregularities and weld defects will be detected and categorized.

Operation Mode ( Simplified)
Input data from the welded seam is captured using TPS and the thermal profiles are transferred to the Weld QAS(System Controller).

The controller and TPS Sequence

• The TPS captures the temperature over the welding joint and sends the data to the
  WeldQAS-control center and evaluates the weld seam quality in real time along with weld process data.
• Calculates the basic parameters and overall Weld Quality Rating
• Applies analysis
• The thermal signature is displayed simultaneous visually by the controller, stored and compared with threshold limits
• Detects weld discontinuities
• Out of bounds signals identify weld defects compared to a known good seam profile and their position if reading from an encoder input.
• The error signal is generated immediately or can be buffered to mark the weld defect area with a marking unit.
• The data is archived in a data base for online review or offline QA and reporting requirements.