How to Decide on the Right Robotic Through-Arm MIG Gun
More and more users of robotic MIG welding systems are switching from the older “over-arm” assemblies to modern robotic through-arm MIG gun configurations. The through-arm MIG gun allows the cable assembly to reside inside the robotic arm, instead of outside the arm, which is where the cable is found in older, over-arm systems.
The benefits of running the cable internally are:
- Cable Longevity: With the cable completely enclosed inside the robotic arm, it is far less likely to wear out from unwanted torsion.
- Cable Isolation: Keeping the cable covered and protected eliminates the chance of it catching on obstructions, or coming in contact with anything that can cause wear and tear to the cable over time.
- Smaller Footprint: With no need for mounting fixtures, the through-arm robotic MIG can handle jobs that demand accurate welding in close quarters. This makes the through-arm especially well-suited to such industries as automotive and aviation.
I. The Power Cable
Rotation, Rotation, Rotation!
Avoiding power cable rotation is one of the key factors in deciding on a through-arm robotic MIG gun. Look for a robotic through-arm gun in which the power connection rotates at a full 360º or greater. With the power connection handling the rotation, the cable can remain free of torsion (twisting), regardless of the complexity of the robotic movement. That will result in longer life for both the cable and the power pin. Another bonus of the rotating power connection is greater flexibility in the types of welds and robotic applications you can use.
You will also want to make sure the robotic through-arm MIG gun lives up to the intended application. Amperage, duty cycle and cooling systems are all things you should consider before choosing. Reliable manufacturers can help you make those determinations. They can also tell you if the through-arm MIG gun is protected from collisions by software application or by a mechanical clutch.
Durability is the keyword here. Protecting the cable in a through-arm robotic MIG gun is pointless if the manufacturer has neglected quality cable construction. Check for excellence in materials, such as Hytrel® tubing, outer covers strengthened with electron-beam accelerators, and cables containing a high copper strand-count.
As you may have guessed by now, the power cable is a crucial component to consider when investing in a robotic through-arm MIG gun. Doing a bit of research beforehand can save you a lot of time and money in the long run.
Always consult the manufacturer’s guidelines before beginning installation of a robotic through-arm MIG gun. Doing so will save you a host of headaches later, ranging from weld porosity from bad electrical connections, to early consumable failure, burnbacks and ultimately, the failure of the whole MIG gun.
General Information for Through-Arm Robotic MIG Installation
- Robot position for cable installation: Make sure robot’s wrist and top axis are aligned at 180º. Also make sure the cable is alligned at 180º, with 2 inches of slack as mentioned above.
- Cable Slack: Make sure the cable has about 2 inches of slack. This will keep the cable relatively loose, which will protect the power pin from unnecessary wear and tear.
Setting up and implementing a preventive maintenance schedule can save you a lot of money during the life of your through-arm robotic MIG torch, and keep your production moving at an economical pace.
A good, thorough preventive maintenance regimen will include the timely checking of:
- Connections: Make sure there are good, solid connections starting at the gun gooseneck and going all the way through the diffuser and contact tip. Also ensure the nozzle is tight, with unworn seals.
- Cable: Make sure the cable leads are fastened tightly according to manufacturer’s recommendations. Also check the cable for small cracks and rips that may develop over time. If the cable needs to be replaced, also check to see that it is installed properly.
- Consumables: Inspect nozzles, contact tips and the gun itself for spatter. Buildup of spatter can cause degrading heat, leading to consumable and even full-gun failure if you allow accumulation.
Some shops also employ a nozzle cleaning station, at which you can remove spatter from nozzles and contact tips and increase the life and usefulness of these consumables.