Peripherals—equipment you integrate into the robotic welding process to make it more effective—can significantly boost the return on investment in your robot. To incorporate and operate this equipment successfully, first understand how peripherals function and then employ some best practices for using them.
Nozzle cleaning stations and sprayers
A nozzle cleaning station or reamer is one of the most important peripherals for your robotic welding system. A reamer removes spatter from the robotic MIG gun nozzle and clears away the debris that accumulates in the diffuser during welding. This helps lengthen consumable and gun life. A clean nozzle also helps improve weld quality and minimize rework.
During installation, be sure your reamer is on a sturdy base or otherwise securely fastened so it doesn’t move around during the reaming cycle. Ideally, you should place the reamer in close proximity to the welding robot so it is easily accessible when cleaning is necessary. 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.
Some additional steps to follow:
Always keep the covers on your reamer. The electronics within a reamer can be easily ruined by moisture from the atmosphere.
Use clean, filtered and lubricated air in your reamer. If “dirty” air goes into the reamer, it will clog up the valves. If you don’t have a lubricator installed on the reamer, use an alternative method to lubricate the air that goes through the motor.
Make sure the reamer diameter is appropriate for the nozzle. It is important that your 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. Use the right blade for the nozzle you have, and set the nozzle at the correct depth within the jaws of the reamer.
When using a reamer in conjunction with a sprayer, protect your nozzle insulator. A reamer can be used by itself or in conjunction with a sprayer that applies an anti-spatter liquid to protect the nozzle, diffuser and workpiece from spatter. Make sure the nozzle is the correct height away from the spray block and that the duration of the spray is about a half a second. Too much anti-spatter liquid can ruin the insulator on your nozzle, and can lead to unnecessary costs for replacement. The liquid may also build up on the nozzle, the robot and the 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 will cause the spray plume to be distorted, which will create inconsistent coverage.
When using a multi-feed anti-spatter system, be sure you have a good quality hoses. Urethane hoses are good options. Also, protect the hoses from spatter that could create a hole and securely fasten them with clamps at every connection to prevent leaks.
Consider using a spray containment unit to capture excess anti-spatter compound. Inspect the unit weekly, and remove any spatter or debris that may have fallen to the bottom. Failing to do so can prevent the unit from draining, which will cause the containment unit to overflow and create a mess.
Robotic welding systems require collision detection to prevent damage to the robotic MIG gun and the robot arm in the event of an impact. Impacts can occur when the robotic MIG gun collides with an incorrectly positioned workpiece or out-of-position tooling. Impact also happens when the gun strikes an item that has inadvertently been left in the welding cell.
Some robotic systems incorporate robot collision detection software. Systems that do not have built-in collision detection, however, should always be paired with a clutch. This is an electronic component that attaches to the robotic MIG gun to protect both the gun and the robot from heavy damage in the event of a collision. In some cases, you may choose to add a clutch to a system that utilizes collision software as backup protection for the robot.
Additional considerations for clutches:
Always make sure the clutch works with the weight of the load. If your gun is not properly supported and the robot moves rapidly to another spot on the other side of the part, the extra weight created by the MIG gun and front-end consumables can move the clutch out of its optimal position.
Reposition the clutch if it gets pulled out of position. If a clutch gets triggered from a collision, reset it by pulling it toward you and letting it snap back into position.
Be sure to check your tool center point (TCP). If the TCP is off center, validate that the clutch is in its home position to ensure the robotic MIG gun is properly aligned for precise welding of the joint.
If you have robotic welding applications that require consistent welding wire stick-out—the distance the wire extends from the end of the contact tip—use a wire cutter. A wire cutter cuts the welding wire to a specified length or stick-out and also removes any balling at the end of the wire.
Most wire cutters can cut a range of different types of welding wire, including both metal- and flux-cored stainless steel, usually up to 1/16-inch in diameter. They can often be mounted on a reamer or used remotely. In conjunction with a wire brake, the wire cutter helps ensure that the stick-out remains consistent.
Neck inspection fixtures
A neck inspection fixture tests the tolerance of a robotic MIG gun’s neck to the TCP. This allows you to readjust it after an impact or if it bends due to routine welding.
The advantage of adding a neck inspection fixture to a robotic weld cell is twofold:
- It ensures the neck meets the specifications of the program for the robotic welding system. Once you have determined the tolerance, you can simply adjust the neck. This can prevent costly rework due to missed weld joints and can also prevent downtime to reprogram a robot to meet welding specifications with an existing bent neck.
- A neck inspection fixture can save you time, money and frustration. When exchanging necks from one robotic MIG gun to another, being able to ensure the neck tolerance is acceptable is advantageous. This is especially true if you maintain a large number of welding robots. You can remove a bent neck and replace it with a spare that has already been inspected and adjusted so you can place the robot back in service immediately.
No peripheral decision
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 provide you with measurable cost savings and profits in the long run. Remember, the goal in robotic welding is repeatability and increased productivity. Any additional equipment that can help achieve these results may be worth your investment.
This article was contributed by Tregaskiss. Tregaskiss is an industry leader in the development and manufacture of robotic MIG welding guns, peripherals and consumables, and offers its products worldwide. Learn more at Tregaskiss.com.