Laser Welding Robots: The Future of High-Speed Manufacturing
As a niche subfield within the broader welding industry, there can be some mystery surrounding laser welding and how to automate it. Understanding the suppliers and components of a robotic laser welding system is critical for beginning your automation journey. Your awareness of these facts is vital to automate this task successfully. This article will cover the above topics to give you the confidence to move forward with your first laser welding robot cell.
An Introduction to Laser Welding Robots
As manufactured components become more complex, demand for precise assembly solutions arises. This issue compounds as plastic manufacturing produces more sophisticated parts. Laser welding provides a solution for these issues. Laser welding also makes welding difficult materials such as copper and aluminum easier. Welding such materials are common in battery system manufacturing. Some facilities will manually weld materials using lasers. However, manufacturers commonly automate due to the high demand for precision.
Types of Laser Welding
Laser welding uses a high-powered laser to generate energy. The laser beam is focused to a fine point, concentrating the heat on a small area. This heat melts the material and allows the materials to bond–creating a weld. There are a few different types of lasers available for welding. Each has its benefits and shortcomings. Therefore, one must be aware of the options before making a purchase decision to avoid mistakes.
Gas (CO2) Lasers
Gas lasers send high-voltage, low-current energy through a gas medium to generate heat. While you can use other gasses (He/Ne, Ar/Kr), CO2 is the most common. Its popularity is due to its efficiency and high-power output.
However, CO2 lasers tend to be more expensive than other laser types. Additionally, they are sensitive devices. Crashes can throw off mirror alignment–a costly problem to fix.
Solid-state lasers use metals or crystals as a medium. Since they are solid-state, no material is consumed during operation. Additionally, these lasers can achieve minimal beam diameters compared to gas lasers.
However, thermal expansion can be an issue. If the medium gets too hot, the laser diameter can become distorted. Additionally, the power output is relatively lower than the CO2 models. This drawback can be problematic for specific materials. As a result, these lasers can struggle with thicker or deeper welds.
Semiconductor (Diode) Lasers
Semiconductor lasers are compact, lightweight, and efficient systems for welding. They don’t require active cooling systems, consume as much power as other options, and don’t use mirrors, making them a durable choice for rough environments.
However, these lasers cannot achieve the high power featured in CO2 models. Also, beam divergence is more prevalent with semiconductor lasers.
Industries for Laser Welding Robotics
Laser welding robots exist as a niche application within manufacturing. Very few industries require the unique characteristics and benefits of laser welding. However, for those industries, access to automated laser welding is vital. Examples include:
- Battery Production
Elements of a Laser Welding Robot System
A robotic weld cell is a complex combination of other subsystems. Initially, keeping track of the required components can be daunting. So, let’s break this system down into its parts:
The welding robot is the central component of the weld cell. Here, the robot refers to the robot's mechanics and controls. Regardless of the type, the robot is responsible for applying the weld. This component both moves and operates the controls of the laser directly. The application requirements should primarily drive robot selection. Robot models feature different design characteristics. When selecting your robot, you should consider ratings like reach, payload capacity, speed, and precision. The application requirements will call for specific performance characteristics that will narrow the types of robots appropriate for your project. We’ll look at some robot selection options in the next section.
The laser system is responsible for generating the welding beam. The laser includes the head and the power generator/amplifier, sometimes a separate component. The material and weld requirements help define the laser type required. Be sure to understand which laser best fits your welding application.
Most laser types require a cooling system to function. Lasers generate massive levels of heat. Consequently, this heat can damage internal components. Cooling systems keep laser temperatures within a functional range. Therefore, laser cooling systems are often part of the overall laser package.
You should consider how you will present the part to the robot for welding. There are often more options available in this area for laser welding systems. This is thanks to the process having a low physical impact on the part during welding. Common options include:
- Other robots
Such a high-tech system comes replete with sensing equipment. Temperature sensors and safety equipment are standard in weld cells. Additionally, beam and seam trackers aren’t uncommon. Suppliers often configure packages with vision systems. These systems can provide a variety of functions. You might prefer different features based on the application. Common applications include:
- Quality control/inspection
- Thermal monitoring
Laser welding is a dangerous application for people. Consequently, it’s essential to implement safety measures to protect employees. Risk mitigation measures commonly include:
- Safety guarding/enclosure
- Light curtains
- Safety scanner(s)
- Lock-out/tag-out systems
- Live-man switch
Laser Welding Robot Types Used Today
A couple of robot types hold a monopoly on the laser welding market. These robots offer the functionality required to automate a laser welding task. However, their differences are significant. Understanding these differences helps you know which is suitable for your application.
Six-axis robots offer a great mix of speed, reach, payload capacity, and reach. These robots can cover the vast majority of laser welding applications. They excel in small to medium-sized welding tasks. Their excellent range of motion helps them weld complex part geometries.
However, the six-axis robots’ shortcomings can limit their compatibility with larger jobs. For example, their reach is limited to a meter or two. Unfortunately, this is the case even for the biggest robots. However, manufacturers can reduce this shortcoming with the help of an RTU. A robot transfer unit (RTU) extends the reach of your six-axis robot. However, this is an expensive piece of hardware. In addition, RTUs carry separate integration costs and considerations.
Additionally, robots will have an upper limit to their payload capacity. This limits their ability to handle the enormous lasers required for some tasks. Unfortunately, you can’t mitigate this limitation without a more robust or different robot type.
Gantry robots provide nearly unlimited capacity for laser welding. Suppliers can configure gantry robots to handle the largest applications. Additionally, their superior mechanical rigidity allows them to move the biggest lasers. Furthermore, their simple design enables gantry robots to achieve unmatched levels of precision.
These benefits don’t come without drawbacks. Gantry robots are limited in their ability to handle complex parts. Six-axis robots are better designed for tasks demanding high dexterity. Their multi-jointed construction allows them to excel in such applications.
Types of Laser Welding Robot Suppliers
Now you have a grasp of the fundamentals of robotic laser welders. Your next likely step is to research potential suppliers. There are many options in the robot welding market. Let’s cover some common supplier types. This clarity allows you to categorize suppliers in your research. Ultimately, understanding which supplier is right for you can make integration a smooth process.
Robot manufacturers design, build and sell robots. Most manufacturers cover a broad range of applications and industries. Some even have unique models optimized for welding in mind. Benefits of purchasing directly from the manufacturer include:
- Direct access to the best engineering support
- Preconfigured options
- Engineered solutions
- Best training access
- Great for standard applications
Integrators are 3rd party solution providers. They’re typically official channel partners of at least one robot manufacturer. Integrators tend to have broad access to other lines of equipment tangential to the robot system. Benefits of working with integrators include:
- Often provide the best local support
- Highly flexible for custom solutions
- Commonly offer a variety of services outside of robotics
System Solution Providers (OEMs)
System solution providers supply off-the-shelf robot packages. These preconfigured systems are purpose-built for a specific application. There are often variations of these packages to cover a broad range of application requirements. Benefits of working with these suppliers include:
- Cost-efficient overall
- Usually built with unique features
- Compatibility with other systems (industry 4.0)
- Quick integration
- System training
You may be ready to take the next step toward automating your laser welding process, but where do you start?
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