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Exploring Multipass Welding
A multipass weld is a weld that consists of a number of singular welds (or passes) layered on top of each other in a specific manner to create a bigger and stronger weld. This methodology is predominantly employed when welding thick sections, engaging in repairs, hard-facing surfaces, or in the course of build-ups. The strength of the joint with multipass is higher than what would be achieved with a single pass weld.
The technique takes into account various process and design considerations such as weld travel speed, weld pool shape, bead geometry, and the heat input of the weld. Modifications in these factors have direct effects on potential solidification cracks, which may occur in both single-pass and multi-pass welds.
In the multipass welding, weld bead depth-to-width ratio is a significant factor; narrower and deeper penetration welds can lead to higher transverse stresses during cooling compared to those with a suitable depth-to-width ratio where stresses are radially dispersed from the weld. It’s worth noting that the number of passes is generally influenced by the thickness of the material being welded – the rule of thumb being, the thicker the material, the more passes it necessitates.
Therefore, multipass welding, while more time-consuming than single-pass welding, affords increased strength and stress relief to the weld area, making it a preferred method for heavy-duty industrial applications. It further allows for precise temperature control, thereby minimizing the risks of hot/cold cracking. Each additional pass also extends the area of the weld, potentially enhancing its resilience depending on the specific application.
When is Multipass Welding Needed?
The necessity for multipass welding arises under several circumstances, grounded in the requirements of the workpiece and the welding process itself. Let’s explore when and why this technique might be employed.
Multipass welding becomes essential when the material’s thickness demands a weld bead size and root depth that can’t be achieved with a single pass. This usually pertains to the welding of heavy-duty components such as thick-wall tubes or full-floater housing ends, where achieving a robust joint with just one weld pass might be impracticable.
Another significant factor necessitating multipass welding is temperature regulation. If a large weld bead is needed but excessive heat input could compromise the integrity of the material, then a multipass weld becomes a sensible choice. This approach enables the material to cool down sufficiently between passes, reducing the risk of overheating, warping, or inducing other forms of thermal damage.
Moreover, the weld’s intended strength and rigidity play a crucial role in the decision to employ multipass welding. For instance, in applications where full strength design is required, welding rules of thumb suggest that the weld size should be 0.750 of the material thickness. Thus, achieving such a size with a single pass might be infeasible, making multipass welding an appropriate solution.
However, it’s important to note that unnecessary extra passes can have negative consequences, such as inducing additional surface warping, and increasing time and resource expenditure. Hence, the decision to employ multipass welding should be based on an accurate assessment of the material’s needs and the welding process’s requirements.
Multipass in SmoothTool: Exploring Available Features
The Multipass system in SmoothTool makes it easy and fast to set up a multipass weld and it lets you add as many passes as you need to get the right weld thickness. Once the base pass is taught, the Multipass system can auto-generate each additional pass based on user input. To achieve a perfect result, SmoothTool lets the user specify the travel- and work angles for each pass in the multipass weld. This level of control helps achieve the perfect result every time.
SmoothTool’s multipass welding system is equipped with numerous features that greatly enhance the effectiveness and versatility of multipass welding.
- Multipass Recreate: The Multipass recreate feature offers the possibility to save the pass structure and data of a Multipass program as a custom profile. You can then load and apply your unique Multipass profile on a new base pass. This feature comes in handy when you are performing multipass welds on similar pieces with a different shape, as it effectively shortens the setup time of these weld jobs.
- Multipass Crop and Extend: In addition to Multipass recreate, we have also upgraded our Multipass feature with the crop and extend functionality, which allows individual passes to be shortened or extended on both ends. This is useful for making stair-like endings. You have full control over the parameters of each pass to achieve the highest structural integrity of the joint.
- Starting Point Selection: This is a function that enables you to start your weld from anywhere. This powerful feature provides the benefit of being able to choose any point in the 3D viewer and set it as your starting point of the weld. This means you no longer have to restart the weld program in order to resume welding in case of production disruptions, as you are able to navigate the cobot to continue welding seamlessly from any placement you choose.
- Change parameters both between and within the passes: The SmoothTool allows you to modify weld parameters on the power source between each pass and also within a single pass. This versatility brings you closer to meeting the specific requirements of your particular welding task.
With these advanced features, SmoothTool provides an efficient and versatile solution for multipass welding tasks.
SmoothTool’s Multipass Benefit: A Closer Look
The Multipass system in SmoothTool brings with it a suite of benefits that makes the process of multipass welding easier, faster, and more efficient. Here are the key benefits of the SmoothTool Multipass system:
Increased Efficiency: SmoothTool’s Multipass system is engineered for a quick and seamless setup of multipass welds. It allows the addition of as many passes as needed to achieve the desired weld thickness. Once the base pass is set up, the system can easily generate additional passes based on user input.
Optimal Control: SmoothTool provides flexibility in specifying the travel and work angles for each pass in the multipass weld. This control level aids in achieving optimal results each time, leading to efficient welding processes and robust joints.
Improved Productivity: The Multipass recreate feature lets you save the pass structure and data of a multipass program as a custom profile. This saved profile can then be used on a new base pass, significantly reducing the setup time for similar but differently shaped weld jobs.
Enhanced Versatility: The SmoothTool Multipass system includes the capability to shorten or lengthen individual passes at both ends. This feature provides complete control over each pass’s parameters, helping attain the highest joint structural integrity.
User-friendly Experience: The SmoothTool’s Multipass system is continuously enhanced with new features, such as extending and cropping passes, and saving and loading profiles. These improvements elevate the functionality and user experience.
Superior Temperature Control: In the multipass system you can specify the time between each pass. This control feature makes it an apt choice for tasks where excessive heat could jeopardize the material’s integrity.
Concluding Thoughts
SmoothTool, with its advanced Multipass feature, is a transformative tool that bridges the gap between the complexities of the multipass welding process and the increasing demand for superior weld quality. It is proof that technology, when harnessed correctly, can significantly augment traditional practices and contribute to the evolution of industries.
As the world of cobot welding continues to innovate and expand, SmoothTool remains at the forefront, integrating advanced features to ease complex processes like multipass welding. Indeed, the ability to meld traditional welding techniques with innovative software capabilities heralds a new era in the welding industry, one marked by unprecedented control, adaptability, and efficiency.
Are you intrigued by the potential of SmoothTool’s Multipass feature and how it can revolutionize your welding tasks? We invite you to explore our other blog posts to learn more about the features available in our SmoothTool cobot welding package. Continue your journey into the world of cobot welding, and discover how our technological offerings can enhance your productivity margin.
Visit our YouTube channel to see more videos of multipass welding in SmoothTool!
