Thread Inspection

External thread inspection

Threads are one of the most important mechanical processes in industrial applications, as they allow different components to be joined together.

MBvision can provide accurate measuring solutions for threaded products such as fasteners, screws… We can inspect size accuracy of metric threads and threads measured in inches.

Our Thread analysis and inspection includes: Major diameter, minor diameter, pitch, thread angle, thread length, number of threads, completeness of threads, edge irregularities, chips, cracks, and gouges, surface analysis, warping.

Thread repair with thread rolling head is sometimes used, before inspection, to minimize the damage that was made on thread during galvanization and transport.

 Inner thread inspection

Since absence, incompleteness, or presence of defects inside a threaded bore can affect production process and the quality of products. The inspection of inner threads in tapped and untapped holes presents a challenge that can be solved with different solutions depending on customers’ demands.

We can offer different methods and combinations of machine vision  and  mechanical inner threads inspections.

Inner thread checking

This method is used for fast detection of internal thread presence, incomplete internal threads, irregular cut threads, double thread, production residues and number of threads. The section of thread is inspected with camera and illumination at certain angle and distance in real time without contact. It is suitable for blind thread holes and through-hole threads.

Multiple Inner thread checking

Is done when higher demands are placed on the quality of an internal thread, in this case we do multiple section inspection of inner thread. By rotating the camera and illumination around inspected inner thread. It takes more time but is more accurate and reliable in detecting defective thread flanks or small cheeps than one section inspection only. It is suitable for blind thread holes and through-hole threads. How deep we can inspect the threads depends on diameter.

Borescope inner thread checking

The method is used when high demands are placed on the quality of an internal thread and the material is porous (castings). The camera lens and light are on the tip of borescope that is mounted on rotating stage with additional movement in and out the thread hole. The pictures are taken while rotating and moving the borescope inside the inner thread. At the end we assemble taken pictures according to the position of both stages and assemble the picture inner surface. Because the camera is mounted under 90 degrees, we can inspect also ruth of inner thread.

A hole thread inspection lens

For inspection we can use hole inspection optics specifically designed to image both the bottom of a hole and its vertical walls. Hole inspection optics are good solution to inspect a variety of different object shapes such as cylinders, cones, holes, bottles, or threaded objects.  But there exist a limited number of lenses to choose from.

Automated GO/NO GO thread quality checking

Go – No Go gauges are mechanical measuring tools used in production lines to guarantee the machining has taken place and it has been performed correctly. They are shaped specifically so the GO gauge passes in the machined area, whilst the NO GO gauge does not.

Our automated stage preforms this test to verify the thread is functional and inspects other Thread parameters: thread depth, number of threads, oversize, or undersized threads, cross threads, thread pitch and Shallow or blocked hole

Confocal sensors for thread measuring

Confocal sensors use light to measure distance in one point with frequency 25kHz and accuracy of 0,5 µm. To measure the inner thread a special sensor with 90-degree angle is used in combination with rotating stage and hight adjustable stage. With movement of the rotating sensor inside the thread hole and high-speed measuring we can assemble accurate inner hole 3D image of the thread.