In the world of welding and cutting there is a wealth of automation options, but what is the right system, the right equipment, for your business? Whether you are just starting an automation line or expanding an existing enterprise, knowing the basics of both robotics and fixed automation options will go a long way in the selection process.

ROBOTICS

Robotics, also known as flexible automation, refers to the process in which a machine is programmed to weld multiple types of joints. This type of welding is very safe and cost-effective. However, professional welders should note three critical choices in machinery: type, size and style.

The two types of robots available are traditional or through-the-arm/compact cabling. In a traditional robotic set-up the torch goes the length of the robot arm. However, with the introduction in recent years of the through-the-arm cabling robot, the torch cable actually runs the length of the robot arm internally, allowing for increased access and reachability.

When determining the size of robot you need, consider your reach requirements as well as the weight of the equipment that will be on the end of the arm. These will narrow the initial field and help determine the appropriate magnitude you need.

Style options include a tabletop robot, floor-mounted robot and gantry robot. The tabletop robot addresses the smaller needs, smaller productions and smaller items of shorter reach — usually 30 inches or less. These robots would primarily address air-cooled equipment, as opposed to water-cooled since it is a smaller, lighter-weight operation with smaller parts. The floor-mounted robot, which is the most common to date, traditionally sits in close proximity to the fixturing for the production pieces, most usually in a welding cell.

Growing in popularity, the gantry-style robot offers increased access, reachability, and space-saving advantages over tabletop and floor-mounted models. Also called Cartesian or linear robots, the gantry-style robots are typically used in welding for pick-and-place applications. Providing the advantage of large work areas and better positioning accuracy, a gantry robot consists of a manipulator mounted onto an overhead system, allowing movement across a horizontal plane.

FIXED AUTOMATION

For a comparison, fixed automation can be explained best as an automated application which is not a robot. Fixed automation is an automated production of multiple parts and repeated parts. Normally the torch or workpiece is stationary, so without the ability to move to another area the process is going to have repeated movements, such as circular or straight welds. Therefore, it is important to consider the type of weld you require when selecting a fixed automation robot.

It is equally as important to consider the “parts accuracy” you desire. Because you will have repeated welds in fixed automation, there is a high degree of accuracy and increased volume production.

No matter the type of process you choose, welding automation almost always increases production, decreases downtime, and improves the quality of parts. The decision between fixed automation and robotics is usually driven by the weld requirements on the production piece.

With robotics, the opportunity exists to have a wider variety of parts in a weld cell because a fixture can be built to accept different parts or to change fixtures for additional parts production. As a result, various software programs have been developed to address these different parts. In fixed automation, there will be a high volume but a limited variety of parts in produced. In the end, your choice should be based on what works best in your facility.

EQUIPMENT CHOICES

With automation options come a) equipment selections and b) equipment choices. Selections are based on the equipment that is necessary for each process, while choices are left to the discretion of the individual welder. So, which elements are considered “selections,” and which ones are considered “choices”?

For robotics, collision detection and emergency stop (E-stop) are selections, because every robotics application will require these. If some type of resistance is identified, the robot will stop so that no damage (or further damage) will be sustained in the robotic cell. Thus, a welder may select the type of collision detection and E-stop system to be used.

Another selection that must be made is between a mount or link arm. In traditional robotic torches the torch cable runs externally, as opposed to the internal cable assembly in the arm cabling. Selecting a mount or link arm is essential because its purpose is to position the torch and conductor tube for programming purposes, as well as attaching the breakaway to the torch body.

Thermadyne Automation offers a full line of conventional and high-precision products, including plasma cutting through Thermal Dynamics and robotics through Tweco and Thermal Arc, as well as oxy-fuel cutting torches from Victor. Its various equipment combinations provide standard TCP (the tool center point), as well as pre-determined positions. Addressing these combinations and positions results in more selection for end users.

Equipment choices are often the more difficult for users, because these are determined by user preferences rather than welding requirements. Two basic choices to be made are nozzle sense and touch sense. Both of these assist the robot with repeatability for automated production — meaning they identify the starting point of the weld, so that every weld is identical. Essentially, they enhance the quality of the application.

The inch switch is a choice similar to what is found in a manual gun, which allows the welder advance the wire by pressing a button. Delivering the same results to a torch gun, an inch switch is an essential element that also provides the best repeatable start position for the user.

Among the choices for robotic torches, one of the best-kept secrets is the purge hose. The purge hose is programmed for use during the purge portion of a robotics application, and is used with an air blast or to inject anti-spatter mist. Anti-spatter mist injected through the gas ports in the gas diffuser coats the inside of the nozzle to prevent spatter build-up, allowing for a better weld as well as prolonged consumable life. Injecting pressurized air through the purge hose as an “air blast” also helps to prevent spatter build up.

Other popular choices include consumables and accessories. Consumables represent a low initial investment, but the cost of these small parts can add up because they require frequent replacement. Accessories are a hot topic in cost justification, too. However, these optional parts improve product quality and extend the parts life of your equipment.

READY TO AUTOMATE

If you are ready to automate your welding process, how do you begin? What do you look for? Start by consulting a professional, such as a distributor and/or manufacturer who is knowledgeable about the application.

Determining the type of welding automation and extras you need is a process of evaluating options. Exploring everything that is available will help you find the best products for any situation.

Robotics and automated production are safe production technologies, and can be a cost-effective alternative to manual welding. Offering repeatability, greater cycle speed, reduction of costs, a safe work environment, and increase in return on investment, robotic automation — flexible or fixed — provides the means for you to remain competitive in any industry.

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Diane Steadham is an automation sales specialist for Tweco Robotics, a Thermadyne brand that produces MIG ARC welding guns, gun kits and accessories. Contact her at diane_steadham@thermadyne.com, or tel. 316-213-8280