Understanding Nozzle Cleaning Stations and Accessories
By Andrew Marchand, product manager, Tregaskiss, Windsor, Ont., Canada, tregaskiss.com. Reprinted with permission: The AWS Welding Journal Reamers help clean GMAW gun consumables, prevent porosity, and reduce changeover downtime and labor
Uptime is key in any robotic welding system. Not only does it help companies increase productivity, but it also supports a solid return on investment in the equipment. The addition of peripherals, like a nozzle cleaning station or reamer, can help further those goals.
A reamer cleans the consumables on a robotic gas metal arc welding (GMAW) gun to prevent spatter buildup that could lead to porosity. This consumable cleaning reduces downtime for changeover, improves weld quality, and minimizes costs. There are two main styles to choose from: standard or Ethernet based. Both provide the same function of cleaning the nozzle free of spatter, with the Ethernet-based reamer providing additional functionalities that some companies find beneficial to their robotic welding operation.
During cleaning, the robot is programmed so that it will dock the nozzle of the GMAW gun against a V-block on top of the reamer, typically during routine pauses in welding cycles. Once the nozzle is in place, a signal is relayed to the reamer to close its clamps. When the clamps hold onto the nozzle, concentric to the cutting blade, another signal is sent to the unit telling the spindle to rise and spin the cutting blade, removing the spatter from the nozzle and gas diffuser.
Many companies also employ an antispatter sprayer that applies a coating of antispatter compound to the front-end consumables after every cleaning cycle. Usually this spray only lasts a half second to avoid saturating the nozzle and wasting the antispatter compound.
Standard vs. Ethernet
A standard reamer features inputs and outputs plugged into a programmable logic controller (PLC), including the inputs that control the nozzle clamping, cutting blade actions, and antispatter spray process. These are the traditional reamers used by many companies.
A standard reamer must be plugged in with a power cord, in addition to having several leads connected to several inputs and outputs, so it may require cord management to minimize clutter.
Ethernet reamers, a newer style, feature a single Ethernet cable that serves as a multipurpose input/output and connects to the PLC. Due to their connectivity, they enable robotic welding system operators to set a program that handles complex equations so they can easily duplicate that program in another weld cell.
Consider a robotic welding operation featuring 100 weld cells that require 50 reamers total. If there are two robots per cell sharing the same reamer, and the reamer program for all 100 weld cells is virtually identical to the first cell, operators can set the program in the first cell to alternate between the two robots and then essentially “copy and paste” that program into the next 99 cells. For this reason, an Ethernet reamer can offer time savings, especially at the integrator level.
With an Ethernet reamer, robotic welding operators can also program a double stroke. If one cleaning cycle wasn’t enough to remove spatter from the nozzle, a signal is sent, as the spindle unit and cutting blade retract, to clean again.
Ethernet reamers can come with an additional Ethernet port, which can be used to daisy chain to other Ethernet devices. This means an operator does not require an individual Ethernet cord run from the reamer to the PLC, from the robot to the PLC, or from the power source to the PLC. He or she can instead run them in a series, together. This cuts down on the number of wires and cords in the cell, further reducing clutter. They also allow operators to monitor the cycle times carefully and more easily troubleshoot any issues that arise.
That said, some older robotic welding operations are not Ethernet ready because they use standard-based signals, and some facilities simply do not have the infrastructure, resources, capabilities, or knowledge necessary to justify the higher investment of an Ethernet reamer.
As with the implementation of any robotic welding system, it is incredibly helpful to have a champion with the skill set to program an Ethernet reamer and oversee its implementation; it can ensure the success of the investment as well.
Regardless of which style of reamer is used, standard or Ethernet based, it should always be programmed with the gun docking to the reamer and the height set properly, following the instructions outlined in the owner’s manual. Always dock the nozzle concentric to the cutting blade, and always supply the reamer with clean, dry air.
Robotic Reamer Accessories
Almost all reamers function the same way, but accessories can be added to make them behave differently or optimize them for a welding operation.
Wire cutting attachments, for example, cut the wire stickout to a set distance so the robot can employ wire-touch sensing. Most operations that use a wire cutting device on the reamer also use a wire brake on the GMAW gun. The wire brake then holds the wire in place at that set distance so it can’t move, keeping it from extending or retracting as the robot moves. The wire brake works well in combination with robots employing touch sensing because it keeps the wire in a set position while the robot searches and accurately locates the weld joint.
Lubricators are yet another valuable reamer attachment. A lubricator applies oil to the air motor impeller, coating the blades so they will not absorb moisture that might be present in the air. Keeping these blades lubricated helps extend the life of the motor and protect a company’s investment in a reamer.
Reamer stands can also be useful. These are essentially a pedestal that an operator can mount the reamer to, with a stand bolted into the floor. Options exist in the marketplace that can be customized to a specific height to help streamline the weld cell layout and those that feature quick-change base plates to facilitate reamer change-outs when necessary.
Spray containment units are also common reamer attachments designed to keep the welding cell clean of antispatter compound. A spray containment unit is a cylinder that mounts on top of the sprayer head to keep excess antispatter spray from bleeding into the open environment in the weld cell.
Another useful reamer accessory is a nozzle detect, which is a proximity switch that detects whether a nozzle is present or not. Occasionally, when a robot enters its ream cycle, there may not be a nozzle present on the GMAW gun; it may have been bumped off during routine movement of the robot arm or from accidentally hitting a fixture. Nozzle detect will recognize the absence of the nozzle or if a nozzle is pulled off during a cleaning cycle. These occurrences are especially prevalent when an operation is using a slip-on nozzle, which is more likely to disconnect.
For large robotic welding operations, a multifeed, antispatter sprayer system may also be useful. This attachment allows up to ten reamers to work off one larger container of anti-spatter compound, eliminating the need for an operator to go into the cell and fill up the smaller sprayer reservoirs attached to every reamer. This reduces how often antispatter levels must be checked and the associated downtime.
Although all these accessories, and the reamer itself, do add to the cost of a robotic welding system, they can also lead to 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 the investment.
Conclusion
In the end, reamers help clean GMAW gun consumables and prevent porosity. They also reduce downtime and labor for changeover. Since cleaner nozzles and other consumables produce cleaner welds, they can help a robotic welding system produce higher-quality products and be more productive.
Reamer Maintenance
While reamers and their attachments are often afterthoughts for many operators, maintaining them properly and ensuring parts are replaced promptly can greatly improve a robotic welding operation’s overall efficiency, quality, and productivity.
All limit switches on a reamer have a life expectancy. For the reamer to work properly, these switches must be replaced if they don’t activate any longer.
Cutting blades also need to be replaced because the edges will become dull over time and will no longer cut as effectively. In some cases, an operator might visually see that one of the flutes on the cutting blade is broken.
Operators must also monitor the reservoirs in antispatter sprayers regularly to ensure they have antispatter compound in them.
Similarly, if an operation is running a lubricator over an extended period, operators will need to refill the oil reservoir on the lubricator. 
