Several months into a new decade, welding technology continues to advance and be implemented on factory floors throughout the world. Yaskawa Motoman's product manager Josh Leath details several trends that may be helpful in moving your operations forward.
Down to a fraction of a micron for repeatability and defect detection, the use of fast and incredibly precise lasers for inspection across industries is optimizing product quality. With automotive, the use of sensors gives the traceability needed for weld seam inspection, and it is also more expedient than wire touch for finding workpieces. Laser sensing can also be used for verifying or measuring assemblies, as well as for tracking a variety of arc and laser weld seams.
Aside from being highly accurate and extremely fast, there are other specifications to note:
Laser Inspection: Robotic workcells are being designed today to complete a thorough weld sequence: 1) check for part position, 2) perform the weld, 3) inspect that weld and 4) provide a pass/fail response.
Aside from checking for quality weld seams, lasers can be used for workpiece inspection, checking to see if parts are in the correct place on an assembly. For example, if there are different studs that need to come through or there are different screws that must be present on a particular weld, each model can be tracked to determine if a part is in place and if it is considered, "good" or "bad."
Adaptive Welding: Lasers can also be used for adaptive welding. This can be done with a simple wire touch sensing, but lasers offer a faster pin-point touch process. With this type of welding, camera systems can be used, as well as high-tech laser inspection systems, to determine the correct start and position of a weld seam.
Furthermore, with this method, the robot's Relative Job function is used to shift the entire job point to be in the ideal space to complete the weld job.
Adaptive weaving, which compensates for variations in the weld joint, can also be enabled by sensor utilization. A laser can be used to track the weld joint path during the welding process to accomplish this, and it can be complimented by thru-the-arc sensors that track the gains or drops in actual voltage and current values to ensure a consistent weld seam.
Data Usage: Harnessing Information to Optimize Production
While a plethora of data (process times, part count, weld parameters, consumption rates, etc.) can be collected on a wide selection of factory equipment, industrial robots, sensing devices and more, learning how to make sense of the data and to harness it for optimizing operations is another matter. Several things to consider would be:
From built-in data collection capabilities to software platforms for factory devices, there are a variety of ways to collect, visualize and use data.
AI Welding: Using Intelligence to Simplify High-Mix Welding
A branch of computer science dealing with the simulation of intelligent behavior in computers, Artificial Intelligence (AI) is one example of how data can be harnessed. More specifically, Machine Learning can build models to classify and make predictions from the data collected (instead of following rules based on algorithms).
For example, a model can be trained, validated and tested through simulation, with the process repeating as necessary to improve the simulation output after each run until the ideal outcome is achieved. A unique example of this process can be seen with IBM's cloud-based AI when it is used to determine the quality of a weld seam using arc soundwaves. In this instance, acoustics from thousands of welds are compared to an initially set standard, before providing a Go/No-Go result based on deviation.
While this type of deep learning is not commonplace with welding, the process of being able to "throw a random part at a robot" is gaining a foothold. Via offline programming software (i.e., simulation software) a part can be scanned, generating a point cloud where the programming software AI can set the weld seam locations and the correct parameters based on the material and process selection.
Welding Trends: Keeping up to Speed
When it comes to welding there are several trends to consider.
With respect to materials especially in the automotive market where the majority of robots are used, there are several trends to note.
Advance Pulse and Servo GMAW
When it comes to welding aluminum and other thin metals, the power supply simplifies much of the process, alleviating the need for a lot of additional equipment. Gas metal arc welding (GMAW) is also utilizing servo torches to mimic the wire control that a human operator has. Traditionally, this is something that has been considered a limitation to some robotic welding applications.
Pulse Wave Function: Allowing less heat input for thinner or high heat conductive metals, this function allows TIG-like cosmetics, even when a welding robot is equipped with a MIG torch. This method is ideal for aluminum and lowers heat distortion on thin steels.
Servo Torch Usage: As power supplies get smarter, more servo torches (or "pull" torches) are being used, dipping and retracting the soft wire (i.e., aluminum) in and out of the weld puddle. This allows for better cosmetics, as well as greater control of depth and energy.
While still costly to implement (compared to other welding methods), laser welding is growing in popularity, especially for certain aerospace applications.
Multiple Weld Options for Dissimilar Metals
Thanks to their growing usage in the automotive industry, there are now several ways to tackle the welding of dissimilar metals.
As greater flexibility is needed in the manufacturing sector to address the wide selection of advanced materials and unique parts being required, more and more mixed processes are being used. This means that a manufacturer may no longer have a workcell just for adhesive or spot welding.
For example, spraying structural adhesive and spray foam may now take place in the same workspace as tacking and welding. Or, steps like inspection may happen at the same time as welding in a workcell to lower cycle time and save floorspace. Jigless operation can also be more useful in mixed lines, achieving greater efficiency.
Typically used for removal of a surface coating, laser ablation uses a lower powered laser to burn off any coating materials rather than the use of dangerous chemicals. This can often ready parts (i.e., high performance automotive parts) for a new coating or for inspection (i.e., a regular surface inspection of airplanes).
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