Testing of internal threads, contactless and in real time.

The optical test system records the complete internal thread.

Generally speaking, the test is carried out over the entire thread length in 4 evaluation windows offset by 90 degrees.

The completeness and the regularity of the threads is checked.

The position and number of evaluation windows can be adapted to the respective test requirements.

Screenshot: Evaluation of a M14x1.5 mm x 12 mm deep internal thread in a through hole. The four evaluation windows offset by 90 ° and cover the entire thread length.

System features

  • Real-time evaluation through intelligent CCD camera during ongoing production.
  • Integrated evaluation software on the camera, i.e., no external computer required.
  • Opto-uncoupled inputs/outputs for monitoring and control tasks for embedding in existing sequences.
  • Integrated narrow measuring head with special optics and lighting.
  • Good integratability in existing test or production systems.
  • The system detects:
    • Thread not present.
    • Thread incomplete.
    • Thread irregular (no correct thread spacing).
  • The complete thread length is recorded and scanned at regular intervals.
  • Bottoms of blind holes are checked, e.g., for cracks, chips and/or colour defects.

Example of a defective through-hole thread, M14x12mm

Faulty thread. Thread flanks not at all or only partially available.
Faulty thread on a wheel flange thread.

Example of a blind hole with internal thread, M4x4.5mm

Blind hole for M4x4,5mm female thread, no thread flanks at all: faulty component.
This internal thread is fine, the number of thread flanks is correct.
Blind hole drilling with chip.

Optical test system for objects with an internal thread of M4-M6x2-5mm


  • Well known optical systems only view from the side into the bore, and may overlook defects on the thread lead-ins and run-outs.
  • The number of 4 evaluation windows can be increased.
  • The system is well suited for retrofitting in existing systems because of its small space requirement.
  • The test is carried out during the ongoing production process.
  • Statistics information such as the number of missing parts or fault rate can be displayed on the monitor.
System for optical control of internal thread and component height.

Wente/Thiedig GmbH

Gewerbepark Querumer Forst
Spechtweg 1
38108 Braunschweig

Tel:              +49 531 / 2 19 45 69 - 0
Fax:             +49 531 / 2 19 45 69 - 99
Mail:            info@wente-thiedig.de