Orbital Welders – A Thinking Man’s Assistant

Good technique is the key for the successful use of orbital welding machines

Orbital welding has become a popular approach to manage welds when the welder is unable to rotate the pipe he is working on or when it is difficult to access the full diameter of the pipe. The weld head (known as a “bug” welder) mechanically rotates the arc around the diameter of the pipe and controls all required torch movements such as travel angle maintenance, travel speed, weave width, weave speed, dwell time, and torch height. Through a simple pendant, the controller allows the operator to input all these torch movements along with the desired weld settings.

One of the advantages of some newer orbital weld systems that have come on the market recently is that when the operator dials them in for a job, he does so using the terminology and units of measure that welders are already familiar with. Older systems typically weren’t as intuitive – something as simple as setting voltage required trial and error since the voltage dial was quite often an arbitrary “1 – 10” dial. It’s not terrible if the welder has to guess the settings for only one variable, but when all the settings are selected this way, the process of dialing in a procedure becomes time-consuming and frustrating.

Some of today’s systems are digitally set with language that welders understand. If a welder can operate a smartphone, he can program an orbital welding machine. However, doing so properly still requires a welder’s know-how.

Having the right operator is essential to the success of the system. The day-to-day operation of an orbital machine may not require a certified pressure welder, but somebody with pipe welding knowledge is required to be at the controls at all times. If an operator has pipe welding knowledge, within a matter of hours he will be comfortable controlling an orbital package like the one described here. At the end of the day, this is a valuable tool that allows a tradesperson to increase their quality and production.

Expertise Breeds Success

Orbital welding machines have gained popularity for use in boiler manufacturing and pressure piping. It becomes fairly straightforward to set the machine in some ways, but it still requires skill. For gas metal arc welding (GMAW), the operator simply sets the wire feed speed in inches per minute and sets the voltage just as he would on a regular machine.

However, with all of these systems, the weave function is a critical setting. The operator must set the controller for the desired weave width, how many inches per minute it should travel the face of that weld, and whether to dwell on either side of the weld. For example, the operator may have a high/low condition where, because of irregularities in the pipe, the left side is a bit higher than the right side. In this case, the operator might program the controller to dwell a little longer on the left side to fill in the joint properly.

This example demonstrates why it is valuable to have a knowledgeable pipe welder running the orbital welding system. The operator has to understand the challenges that arise at different positions on the pipe with any weld. If the welder is working in a 5G position on a pipe, he has to know that starting at about 4 o’clock on the pipe, the weld becomes a challenge because of the force of gravity. Likewise, if he is using a flux-cored process, from 2 o’clock to 12 o’clock slag inclusions can be an issue, and a certain torch drag angle will be necessary to make sure these inclusions don’t occur.

Even if the fit-up is good, pipes are never the same. They never fit perfectly, and someone has to think on-the-fly and say, “My gap varies a little bit here; what do I need to tell the machine to do to compensate for that?” or “When I get to this area, the gap opens up, so I need a little more fill. My choices are to either turn down the travel speed or turn up the wire feed speed.” The operator has to recognize those issues and make a determination of how to attack it. There are many examples of why a skilled operator should work an orbital system.

As a result, orbital welding systems make the welding process very repeatable and more precise than a manual welding process. For instance, when carrying out GTAW on a small-diameter pipe, an experienced operator working by hand will know the optimal work and travel angles he wants. However, it can be physically impossible to achieve the accuracy required. The orbital system takes those physical limitations out of the equation.

Pictured here is Lincoln Electric's orbital welder, which consists of a Helix bug and the Apex controller. The bug mechanically rotates the arc around the diameter of the pipe and controls all required torch movements such as travel angle maintenance, travel speed, weave width, weave speed, dwell times and torch height. Through a pendant, the controller allows the operator to input all these torch movements along with the desired weld settings. Images courtesy of Lincoln Electric.

Joint Prep for Welds

Depending on which welding process is being performed, there are different ways to prepare the weld before the orbital system is utilized. For GTAW, it’s highly recommended to use edge prepping equipment to put a J prep on the pipe ends for consistent root welds. In GTAW situations where a J prep isn’t possible, consumable inserts can be used; this, however, is slightly trickier to set up, and there is a cost to the inserts.

When it comes to wire-fed welding processes, the equipment is capable of welding an open root with GMAW, but most operators prefer to weld the root by hand, just as they normally would, and then use the orbital machine with FCAW for the fill and cap. This allows them to use a standard 60-degree included angle joint prep.

The mindset of the shop is important to take into consideration as these tools are introduced. There’s often concern that any level of automation will eliminate someone’s job. It’s very important for a facility that is looking to implement orbital welding to communicate to the staff that by embracing these tools that increase quality and productivity, they are strengthening their organization and actually increasing job security. If they are able to work safer, better, and faster… what more could they ask for?

Brian Szenasi is the district manager for Alberta for Lincoln Electric Canada, 905-565-5600, www.lincolnelectric.ca.