Key Questions to Ask When Ordering Laser Vision Seam Tracking System

Welding without weld seam tracking is like trying to draw a straight line while riding in a car over potholes — it’s not going to end well. 

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In high-speed manufacturing or custom fabrication, seam tracking keeps welds consistent, airtight, and structurally solid. 

Traditional setups use those expensive sensors and rigid programming, but cobots? They’re out here tracking seams in real time, adapting on the fly, and making welding automation smarter and way, way smoother. (Which is why we’ll also throw in an awesome cobot at the end.)

In this article, we’ll cover:

• What is weld seam tracking?
• Traditional seam tracking vs. cobots for seam tracking
• Technologies used in weld seam tracking
• Benefits and challenges
• Best use cases 
• How to choose a good tracking solution
• Trends of weld seam tracking with cobots

What is Weld Seam Tracking?

Ever tried to draw a straight line on a shaky bus? That’s what welding without weld seam tracking is like — except instead of a wobbly doodle, you’re left with bad welds, wasted materials, and a boss who suddenly questions why they hired you

Weld seam tracking fixes that by making sure robotic welders stay locked onto the seam, even if the material shifts or the setup isn’t perfect.

Here’s how robots keep their welding game tight:

• Laser-based tracking: This system shoots a laser at the seam to map it out before the welding even starts. Think of it as giving the robot night vision goggles so it never loses track of the weld path.
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• Vision-based tracking: Cameras and AI work together to watch the seam in real time, adjusting on the fly to prevent welds from looking like your first attempt at using guyliner.
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• Tactile tracking: A probe physically follows the seam, guiding the robot based on feel. This is especially useful when the weld is buried under dust, grime, or whatever factory nightmare is making visibility impossible.
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• Arc sensing: This method tracks changes in electrical resistance within the welding arc itself, letting the system detect where the seam is without any fancy cameras or lasers. Perfect for when high-tech gear isn’t an option.

Traditional seam tracking vs. cobots for seam tracking

Old-school weld seam still works, but it's clunky, expensive, and makes you wonder why you're still dealing with it. But cobots are more user-friendly, faster, and make fewer mistakes — they’re a major upgrade. 

Here’s how traditional systems and cobots stack up:

Here’s why cobots are winning:

• Less “oops” factor: Cobots use AI and real-time tracking to self-correct, so you don’t have to babysit every single weld.
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• Adapts like a baws: Unlike traditional systems that need a new program every time you switch a weld type, cobots can learn and adjust as they go along.
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• Less training, more doing: Don’t need to base your life on your robot wrangling know-how — cobots are made to be user-friendly.

What technologies are used in seam tracking for welding cobots?

Cobots have got a whole arsenal of high-tech tools making sure every weld is clean, consistent, and on point. Instead of relying on human guesswork (or hoping for the best), these bots use AI, sensors, and lasers to follow seams like a bloodhound tracking a scent.

Here’s how cobots pull off precision seam tracking:

• Robo-vision and AI-driven tracking: Cobots use cameras and AI to detect seam locations in real time, adjusting on the fly. A built-in GPS that actually works, yes. 
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• Force and torque sensors: These sensors help cobots detect slight shifts in the workpiece, so they don’t just blindly weld where they “think” the seam should be. More awareness, fewer mistakes.
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• Laser seam tracking: High-powered laser beams map out weld seams with pinpoint accuracy. Basically, it’s Iron Man-level tech means every weld is in the right place.
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• Hyper-techie software integration: Platforms like RoboDK and Standard Bots’s AI-powered welding solutions make it easier to sync cobots with existing welding setups. They scan data in real time, adjusting heat, speed, and positioning to keep quality top-tier.

Why this tech matters:

• More accuracy, less scrap: AI and vision-based tracking mean no misaligned welds or wasted material.
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• Ditch the unnecessary hand-holding: Cobots adjust automatically, so operators don’t have to constantly tweak settings.
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• Easier to scale: Seam tracking tech makes cobots adaptable, so they’re not locked into one job forever.

Benefits of seam tracking cobots 

Welding by hand? Cool if you like uneven seams and praying to the welding gods for consistency. But if you actually want clean, repeatable, high-quality welds without the stress, cobots are the way to go. 

Here’s why cobots make weld seam tracking a no-brainer:

• Nix the "oops" moments: No shaky hands, no accidental slip-ups — just perfect (or well, as close to as possible) welds. 
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• Scrap metal is not a personality trait: You know what’s expensive? Messing up a weld and tossing out materials. Cobots mean fewer mistakes, less wasted metal, and more money for actual useful things (like better shop coffee).
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• Setup that won’t make you rage-quit: Traditional welding robots need a maze of sensors, calibration, and possibly an exorcism to get running. Cobots? Plug them in, set up the tracking system, and let them do their thing. No IT degree required.
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• Plays nice with humans: Old-school industrial robots need a safety cage like they’re about to go full Terminator. Cobots work with welders, not instead of them, making your shop more efficient without turning it into a robot-only dystopia.
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• Welding without lung damage: Fumes, sparks, and eye-searing light aren’t great for long-term health. Cobots handle the high-risk parts, so you can spend less time inhaling toxic air and more time doing things that don’t require a respirator.
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• TIG, MIG — they do it all: Need precision TIG welds? Fast MIG work? Something even weirder? Cobots swap tools and adapt, so you’re not stuck buying a new machine every time you change processes.

Challenges and limitations of weld seam tracking cobots

Cobots are great, but they’re not magic. (Yet.) While they make weld seam tracking way easier, they still come with a few hiccups that can trip you up if you’re not prepared.

Here’s where things can get tricky:

• Curvy, weirdly shaped welds? Cobots get confused: If your seams look like they were designed by Gaudi, some tracking systems might struggle. Complex weld paths need high-end sensors and AI, or your bot will start welding like it’s lost in a maze.
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• AI isn’t that smart, bro: AI seam tracking keeps improving, but it’s not perfect. Sometimes, it misreads seams, especially with reflective materials or inconsistent surfaces. Just because it’s a robot doesn’t mean it’s incapable of bad decisions. (They’re getting more human every day.)
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• Slower than traditional welding robots: Industrial welding robots that run pre-programmed paths are fast. Cobots, since they’re adjusting in real time, sometimes move slower to get more accuracy — which is great for precision but not always for speed.
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• Not always cheap upfront: If you’re running a small shop, dropping cash on high-precision seam tracking sensors might hurt. The good news? The investment usually pays off in saved materials and better weld consistency. Think $10k to over $50k.
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• Still needs a little babysitting: While cobots are way easier to use than their industrial cousins, they still need occasional human intervention — especially when working with tricky seams or different materials.

Best use cases for cobots in seam tracking 

Cobots are slipping into fab shops everywhere, making life easier for businesses that don’t have time for inconsistent welds. But where do they really shine?

Here’s where cobots dominate weld seam tracking:

• Short runs, high precision: If you’re making limited batches of custom parts, cobots are clutch. They adapt quickly, so you’re not wasting hours reprogramming for every tiny design change.
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• Industries that switch things up a lot: Automotive, aerospace, and other industries that constantly tweak designs love cobots. They don’t freak out when you throw new specs at them.
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• Hard-to-reach welds: If your seams are tucked into tight corners or awkward angles, a cobot with laser or vision-based tracking can sneak in there way better than a human or a bulky industrial robot.
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• When real-time adaptability matters: Some materials shift slightly during welding (looking at you, thin aluminum). Cobots track seams as they go, adjusting in real time instead of following a rigid pre-set path.
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• Shops that don’t want a full-blown robot army: Not every business needs a massive, fully automated welding setup. Cobots give smaller manufacturers a way to improve weld quality without dropping seven figures on an industrial automation overhaul.

How to choose the right seam tracking solution

You have to choose well — some systems are basically the ‘My First Welding Kit’ version, while others are high-tech geniuses. Picking the right one means balancing cost, precision, and how easy to use they are. 

Here’s what to mull over before committing:

• Material type and thickness: Some systems handle ultra-thin metals like a pro, while others freak out at anything thicker than a soda can. Make sure the tracker is actually built for your material.
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• Welding speed requirements: If your production line moves at the speed of light, a sluggish seam tracker is gonna slow you down. Check if the system can keep up with your operations. 
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• Budget constraints: The good news? You don’t need to drop Tesla money on a seam tracking system. The bad news? Cheap solutions often mean cheap results. Find a solid balance. 
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• Software compatibility: If your existing setup and the new seam tracker speak different programming languages, you’re in for a tech nightmare. Look for systems that integrate smoothly with what you’ve got on hand. 

Integrating cobot-based seam tracking efficiently:

• Start small — test on a single workstation before rolling it out everywhere.
• Train your team, or they’ll treat the new system like it’s a UFO.
• Use AI trackers that improve over time instead of yesterday’s tech.

Trends of weld seam tracking with cobots

Seam tracking is leveling up — fast. AI, sensors, and automation are making welding smarter, and manufacturers who don’t adapt will vanish into thin air like the Avengers at the end of Infinity War. (“Mr. Stark, I don’t feel so good.”) 

What’s trending now:

• AI and machine learning upgrades: Welding cobots are getting smarter, learning from each job to improve precision. 
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• Better sensors, fewer mistakes: New tracking sensors can handle tricky weld geometries, reflective surfaces, and even dirt-covered materials. Out go the excuses. 
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• Labor cost reduction: Fewer human errors = less wasted material + fewer reworks = saving money. Math checks out.
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• Cobot adoption is skyrocketing: More industries are ditching traditional automation for flexible cobots that are easier to program and take up less space. Expect to see them in places you’d never expect — like shipbuilding, aerospace, and even artisan metalwork.

Summing up

The idea behind weld seam tracking is keeping up with an industry that’s evolving at record speed. 

We’re talking AI systems, smarter sensors, and cobot-centered automation are making welding easier, faster, and more precise.

Basically, it’s time to embrace automation or become one of those “artisanal” fab shops that are basically museums. Not a good look. 

Next steps with Standard Bots’ robotic solutions

If your welds look like they were drawn by a toddler with a crayon, it’s time to upgrade. Standard Bots’ RO1 makes weld seam tracking effortless — precision, efficiency, and automation all in one.

• Affordable automation: Get top-tier six-axis welding automation for half the cost of competitors, or lease it for just $5/hour. No other cobot has an 18kg payload at this price range. 
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• Precision at every weld: RO1’s AI-powered seam tracking keeps your welds clean, consistent, and free of defects. 
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• Smart and adaptable: No complicated setup — RO1 learns as it works, improving accuracy over time. It’s super easy to set up with its no-code framework. 
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• Safety-first design: No sparks flying in the wrong direction. Built-in sensors keep things safe for human workers.

Every automated welding process has its own unique challenges. Components are not absolutely identical, positioning during clamping is not always the same and heat from the process can cause material distortion. With manual welding, an experienced welder can compensate this directly without any problems. A welding robot or automatic welding machine needs the "eyes" of a human in a different way in order to recognize the individuality of each component and create the perfect weld seam.

In this e-book, we present different approaches to automated welding in order to produce a perfect weld. You will learn about "seeing" and "thinking" methods, understand their principles and deepen your knowledge of optical seam tracking. You get a direct comparison of optical seam tracking with one line and with three lines. You will learn what makes a good seam tracking sensor and when a corresponding investment is worthwhile for you. A sample calculation illustrates the cost-benefit factor.

Using various practical applications, you will learn about the wide range of possible applications, which in some cases allow completely unexpected additional optimizations.

So if you are thinking about the topic of optical seam tracking, this e-book is just the right introduction for you!
 

Optical seam tracking is used to recognize the joint to be welded and to follow its actual course. The sensors used for this have adaptive control. This means that they detect geometric deviations such as edge offset, gap width, seam width and seam volume and pass this information on to the system, which in turn directly adjusts the welding parameters. The seam properties are recorded using laser triangulation (light section method), transmitted to the guide machine and adjustments are made almost in real time.

If you want to use an optical system, it is important that the joint has clear geometric features. These features must be aligned within the view of the sensor. Any feature, such as a butt joint must have a gap or mismatch (hilo) greater than the resolution of the sensor. A square edge butt joint with a very small feature is a challenge for an optical seam tracking system, but can often be worked with if the joint has a small break or radius on one edge.

Contamination or damage to the workpiece surface may lead to measurement inaccuracies. The same happens with highly reflective surfaces that resemble a mirror. More on this coming up.

How laser triangulation works

Laser triangulation is a process for detecting, measuring and analyzing the surface of a workpiece. A laser projector in the sensor head projects a laser line, usually red, onto the workpiece. The light of the laser line is reflected by the surface of the component. The CMOS camera – Complementary Metal Oxide Semiconductor – in the sensor head records the reflected light. This camera is arranged to view the laser line from a special angle (triangulation angle) and records its shape and position. Depending on the distance between the sensor head and the workpiece surface, the reflection arrives at a different position in the camera image. The position and shape of the laser line are measured and analyzed in the camera image using algorithms in the sensor. This information is transmitted to the robot controller or welding machine and used to control it.

If necessary, the welding path of the robot torch is corrected. The great advantage of this is that the measurement is continuous. This makes laser triangulation very suitable for use for tracking all the way along the seam.

Laser triangulation can be used on all materials such as structural steel, stainless steel, aluminum, titanium, copper and brass, and even on non-metallic materials such as plastic and the like. However, it depends on their reflection behavior. Problems only arise with very highly polished surfaces that resemble a mirror. The reflections then scatter so much that the camera is no longer able to clearly distinguish what it is seeing.

The sensor must be setup correctly, starting with a good mounting position so it can see the seam clearly and then telling the sensor where it needs to track to produce the perfect weld. We will go into a little more detail below.

Mounting the sensor

The first step is to mount the sensor in front of the welding torch. The position of the sensor must be chosen so that:

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• the sensor can see the seam clearly
• the sensor is measuring just in front of the welding torch, so it can measure the actual position of the seam just before it is welded

Setting the parameters

For each weld the sensor is to track, the sensor needs to be set up so that it knows what to measure and what the joint is expected to look like.

For the joint:

• Settings to optimize the sensors view of the surface
• Shape of joint (joint type, angles, curves, bends, etc.)
• Where the welding wire should be positioned

The robot controller

As for all robot welding systems, the robot controller needs to have an accurate Tool Center Point (TCP). When using an optical seam tracking sensor, the robot controller also needs to know the mounting position of the sensor in front of the welding torch. This is done by a special sensor calibration routine in the robot controller and a calibration plate. The robot moves the sensor over the calibration plate and uses the sensor measurements to calculate precisely where the sensor is mounted relative to the welding torch.

Transferring the data

The sensor and robot controller talk to each other using an Ethernet connection using the TCP/IP protocol. The robot controller tells the sensor when to make measurements and which joint is about to be welded. The sensor then sends to the robot controller the position of the seam under the sensor, as well as additional information on the geometry of the seam. The robot controller uses the measurements of the seam position from the sensor to calculate the correct path over the seam to produce a good quality weld. It can also use the geometric information to adapt the welding process, if required.

Challenge: look ahead distance and field of vision

Online seam tracking systems work with a look ahead (preview) distance between the sensor measurement and the welding torch. The sensor look ahead distance is necessary in order to:  

a) give the robot reaction time for path correction and
b) to avoid looking directly into the weld pool and welding arc.

The challenge here is that the look ahead distance must not be too long so that the measurement can take place as close as possible to the TCP. There also has to be enough time to process the measured data. For certain welding processes, such as submerged arc welding and processes with additional wire feed (TIG with wire feed) the sensor is usually mounted further away from the welding point to be clear of the flux or wire feed.

However, it is important that the joint remains within the sensor's field of view. Depending on the bend of the joint, this can be more challenging. The programmed robot positions must ensure that the sensor has a good view of the seam at all times.

The main arguments for three lines are:

1. It allows the sensor to make additional measurements, such as orientation of the part to the seam

→ Fact is: It is not possible to send sensor data to the robot using any of the standard robot interfaces, such as those from ABB, Fanuc, KUKA, Yaskawa, etc. The welding robots cannot use these additional information at all. This means that the robot is not able to use any additional information.

2. The measurements are faster with 3 measurements per image than with one measurement per image            

→ Fact is: Most robot interfaces can only transmit approx. 15–20 measurements per second to the robot controller. So even with 1 line the sensors are already faster than most robot controller can accept measurements.

3. With 3 measurements per image there is a high degree of reliability with regard to the correctness of the measurements               

→ That means: Having 3 measurements in each picture means that these 3 measurements can be checked against each other to ensure that they are selfconsistent

→ Fact is: Software with 1 line compares every measurement with previous measurements and makes sure that they are within acceptable limits. Very good sensors with 1 laser line even have the ability to specifically check for regions with tacks and block any incorrect measurement when detecting a tack.

Typical questions for comparison

Why do sensors with 3 lines exist?

These sensors were developed primarily for applications where speed is the main focus. Here, sensors with 3 or 5 lines can have advantages.

Did the developers of sensors with 1 line develop this type of sensor because it is easier?

No, a 1-line sensor is the better choice for general welding applications.

3 lines give more information about the seam orientation.

In principle, that’s correct. However, the interface between sensors and the standard industrial robots like ABB, Fanuc, KUKA, Yaskawa, etc. for seam tracking don’t let you make use of this information.

Measuring is faster with 3 lines.

With 3 lines you can potentially make 3 measurements with every camera picture. However, most robot controllers can only process 15–20 measurements per second. Two additional lines such as those of a 3-line sensor can therefore not be processed by the robot controller. Since both a 1-line sensor and a 3-line sensor work with more than 30 measurements per second, a faster measurement brings hardly any advantages.

With 3 lines and so 3 measurements in each image, you can check whether the measurements are consistent before they are transmitted to the robot controller. But: Good 1-line sensors have a software filter that checks whether the measurements are consistent with previous measurements and uses this to filter out any inconsistent measurements. Some sensors also have a specific software filter to help stop spurious measurements when going over tack welds.

Needing all 3 lines over the seam means that using the sensor to measure the position of smaller features is not reliable. You have to have all 3 lines on the part to get a measurement at all. If the scan runs over a tacking, there is no seam tracking at this point. Since all 3 lines are also needed to detect the start and end of the joint when measuring with a 3-line sensor, this does not work as expected in some control systems.

High tolerances

• Situation & challenge

A Tier 1 supplier for the automotive industry welds commercial vehicle ladder frames, among other things. Due to the tolerances in both the position and fit up of the raw parts, it was necessary to use very wide weld seams with a lot of filler material to ensure a secure connection. This resulted in a high cycle time and high consumption of filler material (welding wire). A cost-saving solution was sought.

• Solution

With the help of a seam tracking sensor, it is now possible to precisely locate and measure the fit up of the welding joint.

• Result

With precise positioning of the weld seams and measurement of the part fit up, the cycle time has been reduced by around 1/3 and production requires significantly less filler material. This saves on cycle time, welding wire use and also on the weight of the product, as well as savings in gas and energy use.

Complicated welding torch position

• Situation & challenge

A leading manufacturer of solutions for water heating, water supply and water treatment equipment produces water tanks, among other things. As there are both lateral and vertical variations in the seam position, different tank diameters require different weld positions, to maintain the required torch alignment. These issues often led to leaks. The company manufactures 4 hot water tanks of this type with different diameters.

For the welding process, the welding torch is mounted to a set of y/z-axis slides which allows the sensor to keep the torch positioned correctly in the horizontal and vertical axes. These y/z slides are mounted to another set of x-axis slides that automatically adjusts the x-position (welding direction) for different tank diameters to position the weld at the correct position (12 degrees) relative to the top center of the tank.

• Solution

Once a seam tracking sensor has been implemented, the system control unit now adapts to a different tank diameter. To do this, the operator selects the tank diameter to be welded on the user interface of the sensor system. The x-axis slide assembly then moves so that the y/z slide assembly remains correctly positioned at 12 degrees from top center for that diameter and the sensor system continuously tracks the actual seam position using the y/z axis.

• Result

The x-axis slide assembly is not controlled directly by the seam tracking sensor, but by pre-programmed movements in the sensor system. This is unique. This solution is now to be introduced in other branches of this company, so they can also benefit from less scrap, less leaks and lower warranty claims.

Are you interested in learning more about Laser Vision Seam Tracking System? Contact us today to secure an expert consultation!