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Welding Robot Systems Main Components and Industrial Use Cases
Key Hardware Elements: Manipulator, Controller, and Welding Power Source
Three core hardware components make up a welding robot system: the manipulator, the controller, and the power source. Manipulators can take the form of a robotic arm, with a variant incorporating six axes being the most common implementation. These components incorporate servo driven joints and high precision reducers to allow for high fidelity motion control. These arms can also control 3D welding paths, making them highly versatile when it comes to solving welding problems involving a large variety of joints and sizes. The controller drives all operations and is highly responsive to changes taking place during the welding operation. It takes uplinked instructions from embedded programs (or teach pendants) and controls the robotic system to carry out welding operations. The welding power source creates and sustains welding arcing to complete joints. During a welding operation, it controls gas shielding, the feed rate for the welding wire, and the welding current and voltage. It takes into account the type of joint being worked on, the thickness and type of metal, and the welding technique most appropriate for the application. The combination of these components creates a highly reliable, automated welding solution. These welding robot systems are used to manufacture automotive assemblies and large machinery, structural frames and components, and to perform welding tasks that require a high degree of quality consistency.
Software and Peripheral Integration: Vision Systems, Sensors and Safety Interfaces
Modern factories are composed of an array of hardware components and smart software solutions. Vision guided systems, for example, are able to find difficult joints and follow seam lines that are constantly moving by using calibrated cameras and edge detection systems. These systems are able to recalibrate their paths on their own, and save the user from having to do it manually each time. Process sensors can communicate changes to voltage arc levels, and measures of heat and current to the central controller. This controller is able to make changes to processes in under a second. Manufacturers will also integrate systems that meet ISO 10218 and RIA 15.06 and stop the movement of a machine to protect an operator when the operator is within a certain distance of the machine. These components are light curtains, specially rated PLC systems, and circuits for an emergency stop that are redundant. A study in the Journal of Manufacturing Systems published last year reported that integrating all of the advanced components of a factory resulted in a manufacturing process that reduced the number of defects in a weld from an average of 37 to zero, and that the factory operated faster.
Important Considerations When Choosing a Welding Robot System
Consider The Type of Joint, the Thickness of the Material and The expected Volume of Production
Choosing the right system involves understanding the specifics of the welding application requirements. Robots capable of making intricate movements and careful welds are needed for welding jobs such as multi-pass fillet welds or tight gap groove welds. However, a simple setup may suffice for producing simple lap welds. For material thinner than 3mm, to avoid burning through the material a method to reduce heat, such as the use of pulsed GMAW, or the use of a welding laser in combination with another process, can be used. For sections greater than 25mm, welding methods that employ a rapid fill and weave pattern may be more appropriate. The volume of production is also a significant factor in the decision. Manufacturers producing greater than 10,000 units per month may find it cost effective to purchase high speed 6-axis robots that incorporate seam tracking and other automation features. Conversely, manufacturers that have smaller production volumes with a greater product variety may find more benefit from a modular and flexible solution. As of last year, the Fabricators Journal reported that about 30% of the issues with robotic welding are the result of a joint shape being incompatible with the capabilities of the robot. For this reason, it is very important to capture the actual welding application requirements from the start.
Payload Capacity, Reach, and Repeatability for Precision Welding
Payload capacity needs to account for all equipment, cable and attached tools. Depending on the job, payload requirements can be around 5 kg for standard arc welding jobs. Reach determines the volume of space the system can work within. Ship building projects typically require 3 meters or more of horizontal reach, while projects involving the assembly of components such as work on car parts require only 1.4 to 1.8 meters. The most significant factor is repeatability, the precision with which the robot can return to the same position with the same accuracy, and the specifications can be very stringent. Applications such as aerospace and medical devices target manufacturing tolerances of +/- 0.05 mm. Systems with the ability to maintain a thermal position of 150 degrees Celsius also eliminate rework due to thermal drift. The 2023 IMTS Manufacturing Report shows that when reach and repeatability are effectively designed, the need for complex workholding is reduced by 27%, and the number of defects is decreased by 40%.
Making a Welding Robot System Fit into a Production Workflow
Cell Design, Fixtures, and PLC Integration
Before you start trying to integrate the welding cells, you have to design cells around the actual workflow. Be sure to plan your layout with at least 1.5 times your robot's maximum reach clear around your welding workspace. It will accommodate ANSI RIA R15.06 safety and maintenance requirements. It also eases the transport of materials around the workspace, and it will give more room for your technicians. Thermal expansion of fixtures is a big concern. Clamping aluminum and stainless welding fixtures is too tight, resulting in a majority, about 15%, of welding issues, according to recent FabTech 2023 research. For integration to be a success, we'll need to address PLC communication. Most of the world operates on EtherCAT or Profinet, and these enable quicker PLC, vision systems, and robot controller communication. These also reduce the time taken to set up an integration task by about 40% and increase the overall efficiency of the production lines.
Modular fixturing uses base plates and locators to facilitate rapid reconfiguration for different part families
One way of error proofing that has been adopted is the use of feedback loops that employ sensors. An example is the use of proximity sensors which can detect if a part is present before the next operational cycle is started
Integrated cable management consists of routed power, signal, and gas with shielded, strain relieved carriers to reduce EMI on control signals
Staff training and planning for the expected timeframe for the return on investment from the time a changeover is completed
For robotic automation to be successful, people skills and the proper equipment are both equally important. With the training we provide to the maintenance team and welders, they are then able to carry out one of the most important disruptive tasks in the new process; change the parameters to optimize the task and troubleshoot the equipment. This training reduces changeover times by as much as 30%. In the weld automation application, the expected return on investment hinges on several factors, including the expected reduction in weld labor costs of $75 per man hour, reduced scrap, consistent quality of all product welds, and the ability to track each product through manufacturing. Based on our experience with many different applications and companies, we expect a return on their investment within 18 to 24 months of starting, with the proper infrastructure built and supportive processes implemented.
Competency frameworks with tiered certifications based on job functions (e.g., operator trending to programmer and then to integrator)
Utilizing digital twin technology, which allows for digital simulations to enable offline path planning and collision free programming without taking the production line down
Implementing OEE dashboards to illustrate actual versus planned production on arc-on time, availability, performance, quality, and loss
Scheduled, proactive maintenance improves mean time between failures by 35%. Weld analytics platforms, which analyze spatter patterns, changing voltage, and travel speed, reduce scrap rates by 22% in mixed production.
Achieving optimal performance and long-term reliability for your welding robot system
Scheduled maintenance and adjustment of arc parameters
Achieving reliable outcomes comes from performing necessary maintenance as opposed to waiting for things to break down first. From following lubricating specifications for axis joints and performing maintenance on the servo motors and circuit cables. This actually eliminates about half of all unexpected shutdowns according to (preferred citation) 2023 research. Another big deal is adjusting welding parameters as necessary.
Data-Driven Improvements Using OEE Monitoring and Weld Quality Analytics
In the context of OEE monitoring, what we are addressing is reliability goes beyond its representation as a maintenance metric and incorporates the potential for growth through continuous improvement. The system logs data where arcs are maintained for extended periods, identifies issues where the end effector deviates from the intended path, and logs incidents of thermal overload. Using this data, the system correlates the performance of the operation relative to others doing the same task and identifies potential issues before they escalate. In the welding domain, AI extends its capabilities to examining the changes in the formation and behavior of weld spatter. It links issues of spatter and nozzle wear and tear and contact tip erosion and gas flow. Manufacturing facilities having varied production experiences reportedly have an approximate 40% reduction in average repair times, and an acceptance rate of over 98% for first-time weld completion is the new norm.
FAQ
1. What are the primary components of a welding robot system?
A welding robot system consists of three primary components: manipulator, controller, and welding power source. These components work together to perform automated welding tasks with high precision and consistency.
2. How does software aid welding robot systems?
Software, combined with hardware, boosts the performance of welding robot systems. Better welding results, shorter setup times, and the ability to comply with safety requirements can all be achieved through the use of vision systems, sensors, and safety interfaces.
3. What factors are important when choosing a robot welding system?
Factors to consider when choosing a robot welding system are the type of welding joints, the thickness of the materials to be joined, the production batch size, and the required payload, reach, and repeatability.
4. What are the integration advantages for welding robots?
The integration advantages of welding robots are the ability to design the cell layout, the fixtures, and the PLC communication. Good integration results in shorter setup times, increased efficiency in the workflow, and timely achievement of operational goals.
5. How can the performance and reliability of welding robots be increased?
More reliable and better-performing welding robots can be obtained if scheduled maintenance is coupled with the tuning of the arc parameters. Making data-driven improvements based on the analysis of OEE and the assessment of weld quality can result in continuous improvement.