Evaluating Options to Shift from Manual to Mechanized or Automated Welding Solutions
From a technology perspective, the welding industry has the potential to enter a new golden age of mechanized and automation welding productivity. Driven by collaborative robot (cobot) technology advances that lower barriers to entry, fabricators are re-examining their options. Below are solutions for moving from manual welding to mechanized welding (MIG) with tractors, submerged arc welding (SAW) solutions and cobot technologies.
As you review these technologies, remember one critical point: begin an automation journey with converting one part, subassembly or even a single weld seam. It can be the simplest, most repetitive weld. Straight lines, circles and squares are easy to automate, which frees your skilled welders for more challenging tasks. By picking a “boring” weld, you set yourself up for success, give yourself some breathing room while you learn, and can more easily evaluate a ROI.
Mechanized Tractors
Mechanized welding tractors clamp the MIG gun (or plasma or oxyfuel torch) to a tractor that runs off 42V from the power source or use the same type of rechargeable lithium-ion batteries used for power tools. They offer the lowest barrier to entry because they leverage the capabilities of standard industrial welding systems, so fabricators can switch between handheld and mechanized operations.
Tractors provide straight-line movement, offer lightweight portability and easily disassemble so they can be moved between work sites. They enable welding with higher parameters, larger diameter wires and faster travel speeds. The average deposition rate for manual welding is somewhere between 5.5-and-7.5 lbs./hr., where mechanizing welding increases the deposition rate to 12 lbs./hr. and 16.5 lbs./hr. Tractors can increase travel speeds by 50%-to-100%. A tractor can move at top speeds of about 50-to-70 ipm depending on the model, where 15-to-20 ipm is common for handheld MIG welding.
Further, by making continuous welds, tractors reduce rework associated with start/stop defects. In applications that need uniform weld bead profile and penetration, mechanized tractors deliver consistency without the cost or complexity of robotic automation. They also reduce operator stress by reducing fumes, UV radiation exposure, and welding in uncomfortable positions.
Tractors for SAW represent one of the stronger automation growth segments, likely due to designs that can be disassembled without tools, hand carried into confined or remote spaces without cranes or other lifting devices and then reassembled in minutes.
Rail, Side Beam and CaB SAW Systems
For fabricators manually welding with cored wires in heavy-industrial applications, switching to a hard automation SAW solution can improve customer responsiveness and help grow the business. SAW solutions start with off-the-shelf components that are then adapted to meet application needs. For example, Texas fabricator Patriot Erectors had secured the contract to weld box beams that were part of canopies for an airport expansion that would require 15,200 ft. of welds just for the main seams alone.
To ensure profitable fabrication and meet the construction schedule, the company shifted from handheld welding to a side-beam mounted subarc solution. This gave them the ability to weld joints up to 25 ft. long, as the entire wire drive, flux hopper, control assembly and drive motors ride on an I-beam with a 12”-wide flange. Instead of completing one or two canopy members per day, the company completed eight-to-12 canopies (depending on shifts).
Orange County Ironworks of Montgomery, N.Y. selected a dual-head gantry-style SAW system. With floor-mount rails that can be extended to match the length of the components being welded and with a width capacity of 10 ft., the welding heads can perform inside welds, outside welds or weld where they are straight up and down. The system is ideal for I-beam and box beam welding with single and twin wire SAW processes.
Where OCI’s fastest and best FCAW operators can weld at about 12”/min manually, the gantry can weld 26”-to-32”/min on each head. That’s an increase of 12”/min-to-60”/min, or a four- to five-fold increase in productivity.
Collaborative Robots
Traditional robots make economic sense for high-volume applications, but moving from manual to fully automated welding is a step too far for many fabricators because of the capital expense and specialized talent required. Additionally, many fabricators focus on high-mix and low- to medium-volume applications, and programming complexity precludes using standard robots.
However, the newest generation of welding cobots excel for high-mix fabrication because they enable fast and easy programming. The starting price point is about $100,000 for an entire package (robot arm, welding table, power source, feeder, cabling, controls). Assembling a cobot package is easy; a skid with a cobot package can hit your loading dock in the morning and you can be welding before noon.
Welders relate to cobots because, like welding, it is a tactile experience. To begin teaching a weld path, cobots typically use a series of buttons located on the robot arm just above the torch. Touching one button unlocks the arm and enables the operator to hand-guide the torch to a start point and set the correct torch angle and distance from the workpiece. Pushing another button records the position of the torch.
Programming a weld path is a matter of recording a series of points and using the robot control pendant or software application that runs on a tablet or smartphone. Programming for most parts takes a matter of minutes, so cobots perfectly adapt to high-mix applications.
Demonstrating Results
Because existing staff can set up and operate cobots, they eliminate the need to add robotic experts on staff. The only way to fully appreciate radical differences between programming a cobot and programming a traditional robot is to personally experience it, and cobot providers will gladly set up a demo.
“When I first saw the cobot, it was exactly what I had envisioned,” said Brett Skyvington, president of Skyvington Manufacturing in Mississauga, Ontario. “It actually lived up to the hype about how easy it was to program — we had guys in the sales demo writing programs on it in the first 40 minutes.” Skyvington researched cobots because the company’s welding department was booked out for five weeks and customer lead times were getting pushed out.
To meet demand for a display for a customer, the company added a cobot to weld 2,600 dividers, 600 tube caps that required about 20 linear inches of welds and secondary welding for gussets for casters. Over the course of the first month, the metrics available through the software app confirmed the cobot made 25,000 welds. Instead of adding a second shift or more staff, the cobot leveraged the skills of existing staff to meet demand.
Develop a Road Map
Regardless of which mechanized or automated solutions you choose, set yourself up for success by creating an automation road map:
- Identify an automation champion, then build a team that owns the implementation and operation.
- Identify the parts to be welded. Pick a simple weld where reduced welding cycle time will make an impact and develop some “before” metrics.
- Work with your automation supplier to make test welds on this part to confirm viability and variables.
- Develop “after” metrics to calculate ROI. Factors to justify investment include labor costs, labor availability, labor skill set (less experienced operators can run a cobot), improved labor environment, predictability (robots don’t call in sick), customer responsiveness/shorter lead times, and growing the business.
- Develop fixturing, jigs and clamps to ensure consistent part positioning and improve part load/unload time. If possible, design fixtures to hold multiple parts.
- Examine fixtured parts for consistent fit-up. If upstream cutting and forming activities introduce variability, it could lead to weld inconsistencies.
- Consider cobot options that include shuttle or rotary tables for faster loading and unloading or mounting the robot on a rail. This so-called “7th axis” option for horizontal movement extends cobot reach for large parts or enables the cobot to service two tables, welding on one while the operator loads/unloads parts on the second.
Cultural Change
Historically, line workers resisted automation because “robots are going to take our jobs.” Cobots have changed that narrative. Welders now see cobots as an opportunity to reduce the physical stress of the job and extend their careers. Cobots appeal to younger people because a job title of robot operator has a “cool factor,” especially for those who learn the controls and metrics. Cobots open the door to those who want to start welding but do not have the required hand-eye coordination or are still learning. Most importantly, cobots act as a force multiplier, enabling the operators to have an outsized impact on production and profitability.
The bottom line is that if fabricators want to increase their competitiveness or grow their business, they can’t throw low-cost labor at the problem. Rather, they need to leverage the talent of their existing staff and attract new staff by using mechanized and automation technology and reimagining their operations.
About the Author: Dan Colvin
