Transmission Tester LTW-1

Measurement of the light transmission on plastic parts provided for laser welding, specifically for housing covers with groove.

The LTW-1 transmission measuring device measures the transmission of plastic parts intended for laser welding.

Your Benefits

The calibration with relevant reference materials allows the use of multiple test devices across different locations. All test devices will provide comparable measurements within the given tolerance range.

In addition, the measurement principle is designed in such a way that the device is optimized for materials with glass fiber constituents.

This, along with a strong application orientated approach makes the device especially suitable for applications in the laser welding process of plastic materials.

The Measurement Principle

The light from a LED passes through a point shaped aperture with 1.5 mm diameter to the sample to be inspected. On the other side of the sample, the transmitted light is caught by the opening of a stainless steel tube with an inner diameter of <1.2 mm.

An optical fiber in the tube receives the light at a solid angle of about 60° and guides it to a photodiode. The photodiode current is proportional to the amount of transmitted light.

This measurement method is in particular best suited for materials with glass fiber constituents.


The configuration and measurement software manages all relevant device settings as well as up to 10 measurement programs (recipes).

Four different operating modes are available as well as the monitoring of Min. / Max values and the data export in CSV format.

The integrated user administration prevents unintentional parameter changes.

More Information

Data Sheet

  • Technical Specifications
  • Dimensions
  • PC-Software
  • Downloads

Areas of Application

  • Quality Assurance
  • Material Qualification
  • Plastic Processing
  • Incoming Inspection


  • Compact workstation solution
  • Easy handling
  • Comfortable configuration
  • Further processing of measured values via PC possible
  • Comparable measurements across different locations
  • Other wavelengths on request
  • Practical measurement methods