Frequently Asked Questions About the TH6D Optical Seam Tracker

Posted by Grecia Rubio on Jun 6, 2019 2:23:06 PM
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How many times have you had to repeat a welding job because of an error in the weld?

How much time has been wasted on stopping production to fix those errors?

The key to an efficient process is the use and organization of time and resources (both human and material). This makes the support of systems and technologies that allow you to efficiently work, one of the best investments you can make.

Let's talk specifically about seam tracking sensors, specifically the TH6D, that is characterized by being universal, precise and resistant.

What is the TH6D system and what does it do?


TH6D is a guide that, through the combination of laser beams and a camera, allows recording of the welding process to follow its path and to be corrected, if necessary, in real time. Based on the concept of triangulation, a laser diode that is inside the sensor creates rays that project on the part to be welded, and are then processed by the camera. The system then interprets that data and sends position information to the movement system. It is important to remember that the TH6D system is suitable for all types of welds and materials to be used.

Now that we know how our sensor works, let's clear up the doubts that have surely gone through your head that have prevented you from acquiring this system.

What is the range of distance that the TH6D has?


The distance of reach is 150mm, while the forward distance in robot applications is 10 to 30mm, and in fixed automation it is 10mm on the low side, as long as the process allows it.

Of course, the resolution of the camera is indispensable to the data being recorded correctly. That being the case, you're probably wondering what is the resolution of the camera that the TH6D has?

The resolution is 0.03mm x 0.07mm at a sampling rate of 60 - 240 Hz.

If we are talking about a sensor that will allow us to detect and correct errors in the trajectory of our welding, we require an exact precision. One of the questions that most of our customers ask us is: What is the speed that the sensor reaches while tracking a seam?

The TH6D system reaches a speed of 6m per min (256 IPM) with the correct configuration. It is even possible to reach speeds of 80 to 120 IPM with good stability.

Onto the subject of materials; we mentioned at the beginning that the TH6D can be used in different types of materials, but ... does it work the same in both stainless steel and aluminum? What about reflective material?

First off, the answer is yes, of course another configuration could be required since the angle of the sensor with respect to the articulation is not very tolerant. As for materials that by their nature are mostly reflective, the system uses an information filter that is implemented by software that will precisely eliminate reflections and any other light coming from spatter or surfaces such as aluminum. So, the issue of the material would not be an impediment to start using the TH6D.


When there is talk of implementing a new system into a process, many doubts arise as to whether it can be used in day-to-day operations, and is not a wasted expense. Therefore, let's clarify what kind of welds can be followed by the TH6D. There are a large number of welds that can be monitored such as:TH6D_FAQ_Image_3

  1. a) "T" Joints
  2. b) Overlapping seals
  3. c) Corner joints
  4. d) Edge joints ("V" edge)
  5. e) Among others ...

Knowing the types of joints that can be followed, another common question arises: Is this system only suitable for arc welding?

The TH6D unit can be used for any process that requires real-time seam tracking including, but not limited to: MIG, TIG, plasma, laser, brazing, cutting, among others. You can also consider the AutoGuide, an integrated product that includes the TH6D sensor, torch mounting base and 2-axis motor to control the positioning of the torch. This can be used for welding with movement or fixed and contains its own control to configure the tracking unit.

Now that we’ve clarified doubts about the performance of the TH6D sensor, another very important consideration comes: What characteristics should our robot have to be compatible with the TH6D system?

Any robot brand can be compatible with the sensor, as long as certain characteristics are taken into account. Generally, the robot will require specific software to support the installation and interpretation of data for motion control. Likewise, most of the connections are made via Ethernet; both analog and digital interfaces are available.


In addition to the clarifications mentioned above, the TH6D sensor has a spatter resistant, optical filter to prevent false measurements and is resistant to faults caused by electric fields.

With robotic welding, getting every ounce of productivity you can out of your investment is key to getting return on that capital investment and meeting your production timelines. Seam tracking is an ideal tool that will bring that efficiency, speed, and accuracy benefits to your automated process!

Topics: Seam Tracking