Historically, if you wanted to automate welding of a part, you needed two key factors: no gaps at the joint and consistency to ensure repeatability. However, in some situations it may be impossible to have one or both of those ingredients.
Paired with the proper software, adaptive welding sensors can drastically improve part quality and consistency while reducing downtime caused by adjustments to fixturing and/or robot programming. Sensors used specifically for robotic welding applications typically fall into four categories: touch, through-arc, laser and vision. Likewise, they have three primary functions: seam finding, seam tracking, and/or part scanning, which often can also be used for inspection. Each function features unique benefits depending on the part and expected outcome, and most technologies can be mixed and matched, where use is not redundant.
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“What is the difference between seam finding and seam tracking?” and “How do I know when to use seam finding vs. seam tracking?” These are common questions our robotic welding experts are frequently asked. With that in mind, here are several things to consider when deciding how to proceed with your robotic welding process:
For a robot to precisely locate a weld joint before welding begins, high-speed seam finding or joint finding is recommended. Work pieces will inevitably have some range of variation, but your goal is to minimize that variation with spec’d parts and fixturing, and be within the half-width of a weld wire into your joint seam. This process can be done in several ways via various technologies, enabling the robot to find the weld joint.
Once the seam is discovered by finding usually two or more known points on the part, the program path is shifted by the robot to complete the weld. The type of seam finding required is dictated by two primary factors: the expected cycle time and the type of joint.
Seam finding is one of the most popular welding functions, and is often achieved through the following tactile options:
Touch Sensing – Ideal for finding the orientation of parts with simple joints and geometries, this method, also known as “wire touch”, involves the physical touch of a weld wire from the end of the torch to detect the conductive surface of the part about to be welded. The slow speed of the robot and the eventual touch complete a circuit with a low amount of voltage fed through the wire. This can also be done with the nozzle of the torch in some scenarios. Completed through built-in features on a welding power supply designed for automation, systems like Yaskawa’s Touch Sense package use a low voltage circuit during a low-speed search to determine the best position for the weld joint.
Pros:
Low complexity; Built-in pendant commands
Works on all conductive material
Easy to teach with macro jobs
Does not interfere with joint access
No external hardware is required on robot
Performs multiple searches with one wire cut
Locates most lap and fillet joint types; can also be used with V butt joints
Offers a lower cost option
Cons:
Requires a wire cutter/wire brake (optional)
Limited to lap joint thickness (>3 mm)
Slower vs. laser or camera
Limited ability to detect joint gap
Cannot find square butt joints
Wire Sensing – Similar to touch sense, where a wire from the torch makes tactile contact with the part, this option uses a servo motor in the torch to rapidly move the wire up and down while the robot moves across the part. This enables easy location of lap joints, and it can measure items like material height and gaps. Offered through Fronius, the Fronius Wire Sense software option provides great efficiency.
Pros:
Can detect joints like butt joints that cannot be easily found using traditional static wire or nozzle touch sense
Can be used for lap joints less than 3 mm
Ability to measure part height offsets and gap width and depths
Cons:
Requires specific hardware and software license from Fronius
Slower vs. laser or camera
Not available on all brands of welding power supplies
Laser Point Sensing – Two to five times faster than touch sensing, the use of a basic, laser dot sensor (that is mounted to the weld torch) captures the location and orientation of a part nearly as quickly as the laser fires, providing fast and accurate seam finding. Capable of working with any welding power supply, Yaskawa’s AccuFast™ non-contact laser sensing solution provides a cost-effective option between tactile and vision sensing solutions.
Pros:
Low- to medium-complexity; Some training required with built-in commands
Works for most materials
Easy to teach with macro jobs
Uses a non-contact sensor
Faster search speeds and touch sensing
Eliminates the need for a wire cutter
Finds most joint types, detecting lap joints down to 1/16” thick
Cons:
Sensor box is mounted adjacent to the torch
Mounting bracket per torch type
Limit in lap joint thickness (>1.5 mm)
Limited ability to detect joint gap
Cannot find square butt joints
Highly reflective material requires evaluation
Laser Seam Finding – Capable of picking up more characteristics in a single scan over a laser dot sensor, the utilization of a profile laser interface, such as Yaskawa’s MotoEye™ SF, provides extremely fast joint measurement. This solution works well with a sensing device that uses 3D multi-laser range imaging optics to provide the needed measurements/joint gap data to the robot before welding begins. Options from SERVO-ROBOT’s i-CUBE™, ABICOR BINZEL/Scansonic and Wenglor work with Yaskawa’s MotoEye SF pendant interface.
Pros:
Works on different materials in all lighting
Easy to teach with macro jobs
Provides joint gap data
Long focal length; mount away from arc
Locates 2.5D; offset and depth
Compact and self-contained
I/O interface can be retrofit to older controls
Cons:
Medium- to high-complexity; Training on vision system suggested
May restrict access into part/tooling
40 mm FOV may require multiple searches for large offsets
Often simplifying programming, this option uses innovative technology to equip the robot to track the weld position in real time, during the welding process. Seam tracking is popular for applications where distortion can occur while welding a part or for heavy cast parts, and it is commonly performed using the following methods:
Through-the-arc Seam Tracking – Best for parts with long or curved seams, varying from part to part, a though-the-arc seam tracker, like Yaskawa’s ComArc LV (low voltage), utilizes a solid-state sensor mounted near the welding power supply to actively measure arc characteristics during the weld sequence. This determines variations between a robot’s taught path and the actual seam path.
Pros:
Low complexity
Reliable sensor and easy to support
Passover function restricts sensor error
Phase Compensation calibrates weld cirucit
Can track lap joints 1/8 in. or 3 mm thick
Supports dual robots and coordinated motion
Offers a lower cost option
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Cons:
Requires weaving and thicker material
Limited by arc/weld physics
Requires a pre-weld search to find the weld joint
Laser Seam Tracking – Suggested for thin material with varying seams that demand the fastest cycle time possible, this method combines a high-performance laser with a high-speed controller to find the seam and part location in real time while the part is being welded. A dedicated program compensates the path, as well as adapts to welding parameters for seam location and variation. Yaskawa’s MotoEye LT or SERVO-ROBOT’s DIGI-I/Power-cam products work well for this.
Pros:
Reliably tracks thin gauge lap joint
Supports high travel speeds (>100 IPM)
Weaving Motion with tracking possible
Tracking is not affected by weld settings
Supports coordinated motion
Ethernet interface available
Camera hardened against welding arc
Adaptive welding function; speed and weld settings
Cons:
High-complexity and often high cost; Training on vision system required
Torch-mounted sensor restricts joint access
Tracking radii is limited to 40-60 mm
Limited to two robots on one system
Dual Laser Seam Tracking – To optimize cycle time, sometimes, two robots are equipped with seam tracking technology to work in unison. This utilizes the same interface and technology mentioned before, but can cut cycle time in half and reach more weld joints on larger or complex parts than a single robot.
Semi-autonomous
Using a laser scanner, point laser and closed-loop control systems, the SWR automatically maintains the torch to pipe distance with 0.1mm accuracy and assists the operator in seam tracking so primary focus can remain on the weld. Depending on the fit up, arc light, and spatters, additional operator input may be required for seam tracking and height control.
Collaborative
As a collaborative welding robot, the SWR is designed to meet all the safety requirements of ISO ; therefore, it does not require fencing or a safety cell. A junior welder can stand beside the robot and make changes during the weld as required.
Long Reach
Among industrial spool welding robots, the SWR has the largest ratio of reach to footprint. With a footprint of 16 sq ft, the SWR has a radial reach of 15’ which allows for welds in pipe modules and spools up to and including 30’.
Ergonomical
Designed for semi-automatic 1G roll welding, the SWR significantly improves the ergonomics of pipe welding by having the robot take on the heavy lifting of a consistent weave motion.
Production Monitoring
The SWR provides repeatability and reliability; The NovData™ logging software captures all available data for each weld pass for future analysis and reporting.
Welding Vision System
The SWR is equipped with a welding vision system which can display the weld to the operator as it progresses and records a video from each weld for analysis and future production improvements.
The base model of the SWR can weld pipes from 2” to 60” with appropriate pipe positioners.
The single torch SWR uses GMAW or MCAW from root to cap.
The dual torch SWR uses GMAW or MCAW for root, and MCAW or FCAW for fill and cap.
SWR uses modified short-circuit waveform on the root, that is STT, RMD or LSC.
TIG is currently not offered with SWR.
Talk to our sales team if you’d like to know more about your specific process.
The SWR can weld carbon and low alloy steels, as well as stainless and nickel alloys. The seam tracking and height control features are only available on carbon steel at this point. Recipe development for nickel alloys is incumbent on customers.
Yes, the SWR has the ability to switch between weld modes without shutting off the arc. The standard SWR process is GMAW with solid wire. The solid wire has moderate levels of silica (not heavy slag). This silica is burnt by the arc as the arc goes over it. Operators can see this throughout the weld process using the welding vision system.
The SWR can easily be integrated to work with different positioners including Team Industries, LJ, Profax, and Preston Eastin. Our team can verify if we can integrate with your specific positioner, brand, make and model.
The robot has the ability to integrate with 2 to 5 positioners in a layout determined by you. The picture on the left shows some of the possibilities with 2, 3, 4 and 5 positioners.
Integrated positioners that are not being used for welding with SWR, can be rolled via foot pedals and used for pipe
preparation, tacking, grinding.
Power source options are Lincoln PowerWave® R450, Miller Auto-ContinuumTM 500, and Fronius TPS 400i LSC Advanced. All units are quoted with a power source.
The pipe/components are fit-up to a typical 3/32 in. (2.4 mm) root opening (gap) with a tolerance of ± 1/32″.
SWR operators are trained to scan the pipe visually prior to the start of the weld for assessing the hi-lo, root gap and inspecting the tacks. If the Hi-Lo is higher than the amount specified by the SWR bevel requirements document, the pipe has to be refitted. If the Hi-Lo is within the allowed tolerances, the operator can enable the torch weave dwell functions. During the root pass, the operator can address the Hi-Lo using the asymmetric dwell and root save to weld the root. During the fill and cap passes, the operator uses the dwell function to manage the Hi-Lo. In this scenario, the laser-assisted seam tracking and height control have to be disabled for all passes to better allow the operator to control the torch
position.
Similar to the Hi-Lo, SWR operators accommodate this scenario by enabling the dwell function on the thicker side of the joint prior to the start of the weld. If the inner diameters of the two sides do not match, operators have to grind down the inside to make sure the toes align as they would do in manual/semi-automatic welding. (Fittings are pre-heated prior to the weld).
Based on industry standards, the SWR falls under mechanized welding, given that the operator interacts with the machine and makes on-the-fly adjustments.
With a 4′ x 4′ footprint, the SWR has the smallest industry footprint where we typically see anything up from 7′ x 30′. Therefore, it does not cannibalize shop floor space and it won’t interfere with production flow.
This depends on your current welding process. One SWR with an operator can produce the same output as 4 welders using SMAW, and 2-3 welders using manual root to cap GMAW.
By eliminating the torch hand control, the mechanized weave relieves welder fatigue so they can expect a higher deposition rate, higher production, faster track speeds and the ability to run pre-programmed
welds.
With just a few details about your operation, we’ll have your ROI calculated. Typically our customers see an ROI of 6-18 months.
The SWR is designed to fit in pipe fabrication shops because the height does not interfere with overhead cranes. In addition, the SWR can be easily parked away to allow shop traffic to pass.
Assuming an integration with two new positioners (from the approved list) , it takes two days to install the SWR and only one day to commission it.
It takes 3 – 5 days to train an operator for both operations and maintenance. Operators need to know the basics of pipe welding. We generally recommended training 3 – 5 operators with at least one journeyman pipe welder.
The operators should know the basics of welding and have some welding experience.
The SWR has qualified multiple WPS to ASME Section IX requirements, including Charpy Impact testing with full mechanical testing (bend & tensile tests) and supplemental hardness testing. WPS can be developed for other codes, as required.
The SWR produces consistent quality welds during production , characterized with low repair rates when non destructively tested with radiographic and ultrasonic examinations to typical ASME B31.1 and B31.3 requirements.
ASME IX Code is quite clear that each organization must develop and qualify their own WPS/PQRs and Welding Operators. Novarc can assist customers with those activities and utilize its qualified WPS/PQRs for reference/baseline. However, customers cannot use Novarc’s WPS as-is for their production purposes as that would be a regulatory non-compliance.
The SWR comes with the NovData™ production monitoring software that produces daily reports. The daily report includes: production time, welding time, pipe diameter and more. It also creates a time-stamped log file with voltage, current, WFS, travel speed and all other relevant weld and motion parameters for each weld.
The SWR also comes with a camera built into its robotic arm. With this feature, operators get a clear view from inside the groove on the HMI as each weld progresses in real time. Novarc’s welding vision system records all videos for future analysis.
Welding shielding depends on the weld process and filler metal. Our technical team can assist you with specific welding applications. The recommended gases for Carbon Steel pipes are the following:- Solid wire: 85% Argon 15% Co2, or 90% Argon 10% CO2
– Metal core: 90% Argon 10% CO2, or 98% Argon 2% CO2
– Flux core: 75% Argon 25%, or 100% C02
The SWR needs 3 phase power and minimum 85 PSI compressed air. The electrical power can be any of
the standard voltages between 208V and 600V.
We replace the existing positioner/rotator motor with a servo motor so the SWR would be able to control it.
The SWR has built-in speed and torque monitoring systems that ensure speed and forces are within required levels at all times.
The SWR is designed to be a robust machine. As a result, only minimal maintenance is required. Maintenance training is included with the robot training. Maintenance is similar to a standard welding machine.
The SWR needs to be anchored to a minimum 6’ concrete slab. However, you can move it between previously installed base locations using overhead cranes.
The SWR is designed for indoor usage. It can be used in the field or in a work yard, provided it is protected from the elements and within the temperature range of 5 – 50 degrees Celsius.
Yes, you can easily copy the data from an SWR to another using a USB.
Approximately lb.
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