Getting the Most out of Robotic Welding

How Peripherals Can Help

antispatter sprayer

If an antispatter sprayer is used in conjunction with a nozzle cleaning station, it’s important that only the minimum amount of antispatter compound required for the application be used.

No one will argue that the expense of implementing welding automation can be significant. Making the investment takes careful consideration, planning, and, in some cases, negotiation with management or owners.

It’s understandable why manufacturers may be wary of adding more costs to a robotic welding system for peripherals, such as nozzle cleaning stations and wire cutters. However, in the course of automating the welding operation, they must evaluate more than just the upfront price of the equipment. It’s also critical to look at the goals for the long-term ROI.

Peripherals, in most cases, can help companies realize the full potential of the robotic welding system, ensuring greater success by establishing more efficient throughput, reducing quality issues, and minimizing unnecessary downtime.

Clean Nozzles

One of the most common and beneficial peripherals, a nozzle cleaning station, utilizes routine pauses in operation, for example during part changeover and tooling indexes, to help maximize the efficiency of the system. Also called a reamer or spatter cleaner, a nozzle cleaning station cleans spatter from the inside of the welding consumables on the front end of the gas metal arc welding (GMAW) gun, including the nozzles, contact tips, and retaining heads.

A nozzle cleaning station contributes to the success of a robotic welding operation in two key ways:

  1. It helps ensure consistent shielding gas coverage by keeping the diffuser gas holes and the nozzle bore clean. This reduces downtime needed to address quality issues and the cost of scrapping a part completely.
  2. It helps lengthen the life of the consumables and the robotic GMAW gun. Longer-lasting equipment reduces inventory costs, minimizes downtime, and helps shorten the ROI.

Gaining the best results from a nozzle cleaning station requires attention to detail. It’s important to program this peripheral to clean the consumables as frequently as is feasible; the cleaner the nozzles, the longer they will typically last. Frequency will be application-specific.

Welders should also always follow the manufacturer’s recommendation for the air pressure and volume of air required for this peripheral to perform to its optimum capacity. The air supply to the nozzle cleaning station must be clean and dry because moisture can quickly damage the motor.

The nozzle cleaning station needs to be placed in close proximity to the robot to make it easily accessible and reduce the time needed to reach it. Reamers can be mounted overhead on an angle, if necessary.

It is important to note that if an antispatter sprayer is used in conjunction with a nozzle cleaning station, the minimum amount of antispatter compound required for the application should be used. Excessive antispatter can lead to unnecessary costs and leave excessive residue on the consumables, equipment, and tooling, which will require labor to clean or replace.

Preventive maintenance of the peripheral is important. A few steps can be taken daily, including:

welding peripherals

Peripherals, in most cases, can help companies realize the full potential of the robotic welding system, ensuring greater success by establishing more efficient throughput, reducing quality issues, and minimizing unnecessary downtime.

  • Visually inspecting the peripheral to determine that all parts are working properly. Look for error messages, if applicable.
  • Cleaning the jaws and V-block regularly.
  • Checking for wear or chips on the cutter blade and for a broken blade, replacing it as necessary.

Accurate TCP Provides Better Results

Maintaining an accurate tool center point (TCP) is important for a robotic welding system to identify the weld joint correctly and complete a quality weld. In the event of a collision, or even through routine welding, the robotic GMAW gun’s neck may bend. A neck inspection tool can help ensure that the neck is properly readjusted for the intended TCP.

Most neck inspection tools are designed to accommodate standard necks for a particular brand of robotic gun. To use this peripheral, the welding operator or maintenance personnel needs to determine the tolerances for the robotic welding program and adjust the bent neck to meet the correct specifications.

While it may seem like a minor service for this peripheral to perform, a neck inspection tool can offer several benefits. By accurately adjusting the neck to the correct angle, the tool can help ensure greater weld consistency, minimize or prevent costly rework associated with missing weld joints, and reduce potential complications and downtime related to reprogramming the robot to weld with a bent neck—a process that some companies employ in the absence of this peripheral.

For companies that maintain a large number of robots, a neck inspection fixture can also help prevent confusion and downtime when exchanging necks from one robotic GMAW gun to another. Welding operators simply remove a bent neck, exchange it with a spare that has already been inspected and adjusted, and put the robot back in service immediately. The damaged neck can then be set aside for inspection while the robot is online.

Protection Against Collisions

In an ideal world, companies would never experience a robotic welding collision. The reality, however, is that unclamped tooling, incorrectly positioned parts, and other such human errors can cause the robot to crash into the hard surface of the part or the fixtures.

Two types of peripherals safeguard against this problem: a clutch and a solid mount. The type chosen depends on whether or not the robotic welding system has integrated collision detection software.

For robots without collision detection, adding a clutch to the system can protect the robot and GMAW gun in the event of a crash. Generally, maintenance staff can calibrate the sensitivity of the clutch to accommodate the robotic welding gun’s mass.

These peripherals function mechanically and electrically. When a collision occurs, the clutch recognizes the physical impact and interrupts an electrical signal to the robot controller, which stops the system and helps prevent damage. It also alerts the personnel overseeing the operation that there is an incorrect variable in the weld cell.

Robotic welding systems that have an integrated collision detection feature and torque software can stop the robot in the event of an impact. For these systems, a solid arm mount can be used without worry. The collision detection software is designed to protect the GMAW gun in the event of a crash.

Both clutches and solid mounts require mounting arms to attach them to the robotic GMAW gun and hold them in a specified position, so the robot can repeat the same weld throughout the welding process. These mounting arms are generally composed of a durable aluminum alloy that can resist breakage during an impact. The insulating disc mounted between the arm and the robot’s wrist is the sacrificial piece, designed to fail in the event of a collision that is not recognized by the clutch or the collision detection software quickly enough.

Neck checking fixture

In the event of a collision or even through routine welding, the neck of the GMAW gun may bend. A neck inspection tool can help ensure that the neck is properly readjusted for the intended TCP.

Having proper collision protection can ultimately help protect the robot and GMAW gun from damage and minimize replacement costs, as well as prevent downtime for robotic GMAW gun repair.

Consistent Wire Length

Robotic welding systems are known for their repeatability. To obtain consistent results, it is often important to maintain a consistent welding wire stickout (the distance the wire extends from the end of the contact, also called electrode extension) when the arc initiates. A wire cutter can help maintain the correct length.

This peripheral cuts the welding wire to a specified length, removing any inconsistencies at the end of the wire. The result is more reliable and smoother arc starts. Companies with robotic welding systems that seam track to find the joint can especially benefit from the improved quality a wire cutter brings. Having a consistent stickout allows for more reliable and repeatable welds by helping the robot to more easily locate the correct spot to begin welding.

Manufacturers offer a variety of wire cutters, most of which are capable of cutting different types of welding wire. These include stainless steel, flux-cored, and metal-cored wires, usually up to 1⁄16 inch diameter. Companies may prefer to mount the wire cutter on a nozzle cleaning station or locate it remotely, according to their needs.

Worth the Investment?

Companies need to be budget-conscious to run a profitable business and keep prices competitive. Investing in welding automation costs money, and the addition of peripherals upfront may seem like an unnecessary expense, particularly for those companies going into welding automation with some trepidation. Making the investment, however, can help poise companies for a faster ROI for their robotic welding system, and prepare them for more growth and greater competitiveness.

The goal is to determine which peripherals will provide the most benefit for the given robotic welding operation. As with any equipment purchase, knowledge is key. Working with a robotic integrator at the time of implementation or with a robotic peripherals manufacturer in the process of retrofitting an existing robotic welding system can help.

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