Robotic welding can be extraordinarily efficient—until it starts producing bad welds. Weld defects have numerous causes, but one culprit can be a dirty nozzle. This is where a nozzle cleaning station, or reamer, can help.
A reamer can be integrated into an automated welding system to maximize its performance (see Figure 1). It removes accumulated spatter from inside the gas metal arc welding (GMAW) gun’s front-end consumables, including nozzles, contact tips, and retaining heads. In doing so, it extends consumables life and reduces downtime for maintenance. It also prevents the loss of shielding gas coverage, a problem that can lead to expensive rework to correct porosity and other weld defects.
The reamer typically takes about five or six seconds to clean a nozzle, while parts are cycling down the line or while the tooling is indexing. It could take more than five minutes for a welding operator to enter the weld cell and do the job manually.
A reamer significantly reduces the risk of spatter lodging between the contact tip or retaining head and the nozzle, which can result in arcing against the part. Removing the spatter frequently also ensures smooth shielding gas coverage to protect the weld pool. By minimizing spatter and debris in the nozzle, reamers help improve the overall efficiency of a robotic welding system.
Reamers are either analog or digital. Analog reamers generally have a multiconductor cord set and an air supply. Each conductor relays a specific task, signaling the system to start, spray, and return to the home position.
Digital reamers use a network cable to send commands to an IP address. They can control individual functions without being limited to the number of leads in the cord set, as an analog reamer is. Beyond being told to start and spray, a digital reamer also can be told to clamp, lift, lower, and turn the motor on and off—all of the functions that make up a ream cycle.
A digital reamer also allows for remote monitoring, which streamlines troubleshooting. If a certain unit is having issues, the operator can monitor the status of each function to determine where the problem lies. This helps determine what is wrong before a part has to be pulled off the line.
A reamer can be mounted in nearly any orientation, as long as it doesn’t allow debris to collect in the clamp housing. For easy access, place the reamer close to the welding robot. If the reamer is on an angle, with the base plate not parallel to the floor, and if it has an antispatter sprayer, make sure that the spray reservoir does not leak when full.
Using a multifeed system can help, as it operates in the same manner regardless of the reamer’s orientation. A multifeed system allows for the feeding of antispatter compound to multiple reamers from a single drum placed on the floor or a nearby shelf, thereby eliminating the need for a sprayer reservoir.
Make sure that the V-block inside the top of the reamer is the correct size for the nozzle, the cutter blade is the correct size for the nozzle bore, and the insertion depth of the nozzle to the reamer is adequate (see Figure 2). Aligned properly, the nozzle should sit tangent on the two angled faces of the appropriately sized V-block.