Peripherals – equipment that is integrated into the robotic welding process to make it more effective – can significantly boost the return on investment you achieve from your welding robot. And incorporating and operating robotic welding peripherals successfully doesn’t have to be difficult. To help, it’s important to understand how your peripherals are intended to function and employ some best practices for using them.
MIG gun clutches
All robotic welding systems require some form of collision detection to prevent damage to the robotic MIG gun and the robotic arm in the event of an impact. Impacts occur when the gun collides with an incorrectly positioned workpiece or out-of-position tooling. They also occur when the gun strikes an item that has inadvertently been left in the welding cell.
Some robotic welding systems incorporate collision detection software. Systems that do not have built-in collision detection, however, should always be paired with a clutch – an electronic component that attaches to the robotic MIG gun to protect it and the robot from heavy damage in the event of a collision. In some cases, a clutch can be added to a system that utilizes collision detection software as backup protection for the robot.
It’s important to make sure the clutch works with the weight of the load created by the robotic MIG gun and front-end consumables. If the gun is not properly supported and the robot moves rapidly to another spot on the other side of the part, the extra weight can move the clutch out of its optimal position.
If a clutch gets triggered from a collision, operators can reset it by pulling it toward them and letting it snap back into position. Afterward, it’s important to check the tool center point (TCP) to ensure the robotic MIG gun is properly aligned for precise welding of the joint. If it is off center, validate that the clutch is in its home position.
For robotic welding applications that require consistent welding wire stickout – the distance the wire extends from the end of the contact tip – a wire cutter is a recommended peripheral. As the name implies, a wire cutter cuts the welding wire to a specified length or stickout and also removes any balling at the end of the wire.
Most wire cutters cut a range of different types of welding wire, including stainless steel, flux-cored and metal-cored, usually up to 1/16-in. diameter. They can often be mounted on a nozzle cleaning station or used remotely as needed.
In conjunction with a wire brake, the wire cutter can ensure that the stickout remains consistent for robots with touch sensing capabilities that help locate the joint.
Neck inspection fixture
Another key peripheral is a neck inspection fixture, which tests the tolerance of a robotic MIG gun’s neck to the TCP so it can be readjusted after an impact or after bending due to routine welding.
The advantage of adding a neck inspection fixture to a robotic welding cell is twofold. First, it ensures the neck meets the specifications to which the robotic welding system has been programmed and, once the tolerance has been determined, the neck can be adjusted accordingly. This can prevent costly rework due to missed weld joints and prevent downtime required to reprogram a robot to meet welding specifications with an existing bent neck.
Second, a neck inspection fixture can save time, money and confusion when exchanging necks from one robotic MIG gun to another. Having this ability is especially advantageous for manufacturers that maintain a large number of welding robots. It allows operators to remove a bent neck and change it with a spare that has already been inspected and adjusted. The robot can then be put back in to service immediately.
Nozzle cleaning station
One of the most important peripherals to consider for robotic welding systems is a nozzle cleaning station or reamer. A nozzle cleaning station removes spatter from the robotic MIG gun nozzle and clears away the debris that accumulates in the diffuser during the welding process. This helps lengthen the life of the gun consumables as well as the gun itself. A clean nozzle also reduces problems that could lead to rework and helps the robot create better quality welds.
During installation, it’s important to ensure that the reamer is on a sturdy base or otherwise securely fastened and not moving around during the reaming cycle. Ideally, the nozzle cleaning station should be placed in close proximity to the welding robot so it is easily accessible when cleaning is necessary. It’s recommended to program the reaming process to run in between cycles – either during part loading or tooling transfer – so it does not add to the overall cycle time per part.
It’s also recommended to always keep the cover on a reamer. The electronics within it can be easily ruined by moisture from the atmosphere. Using clean, filtered and lubricated air in a reamer is also beneficial. If dirty air goes into the reamer, it clogs up the valves. If a lubricator isn’t installed on the reamer, there are alternative methods to lubricate the air that goes through the motor.
It’s important that the reamer matches the diameter of the nozzle and that the blade does not hit the diffuser or nozzle when it goes through a ream cycle. Furthermore, use the right blade for the nozzle and ensure that the nozzle is set at the correct depth within the jaws of the reamer.
A reamer can be used by itself or in conjunction with a sprayer that applies an anti-spatter compound to protect the nozzle, diffuser and workpiece from spatter. Make sure the nozzle is the correct distance away from the spray block and that the duration of the spray is about a half a second. Too much anti-spatter compound can ruin the insulator on a nozzle and lead to unnecessary costs for replacement. The compound may also build up on the nozzle, robot and parts being welded, resulting in additional cleanup.
Frequently check that the sprayer and sprayer head is free of debris; if spatter gets inside the sprayer head, it causes the spray plume to be distorted, which creates inconsistent coverage.
For multi-feed anti-spatter systems, it’s essential to use a good quality hose, such as a urethane hose, and protect it from any spatter that may hit it and create a hole. Also, securely fasten the hose with clamps at every connection to prevent leaks.
For those who use a spray containment unit to capture excess anti-spatter compound, weekly inspections are recommended. Remove any spatter or debris that may have fallen to the bottom. Failing to do so can prevent the unit from draining, which causes the containment unit to overflow and create a mess.
The decision to invest in robotic welding equipment is significant. It requires time, knowledge and a trusted relationship with a robotic welding equipment manufacturer to find the right system. The same holds true for peripherals.
Although these devices do add to the initial cost of automating, they can lead to measurable cost savings and profits in the long run. Remember, the goal in robotic welding is repeatability and increased productivity, and any additional equipment that can help achieve these results may be worth the investment.