Blended gas minimizes the burr in carbon steel cutting and reduces nitrogen assist gas consumption
February, 2024- Assist gases are an integral part of laser cutting, but they can be a big, ongoing expense, given the price of bulk nitrogen. MC Machinery, Elk Grove Village, Illinois, a North American supplier and servicer of Mitsubishi lasers and automation equipment, has developed advanced gas-reduction technologies AGR-N2, AGRAIR and AGR-MIX, which can help decrease consumption and make a big dent in the overall annual cost of running a laser.
Ryan Conroy, laser product manager for the company, says the AGR technology’s main goal is reflected in its name. “What started this was looking at reducing nitrogen consumption, which we achieve using a special nozzle that shrouds the nitrogen with low-pressure air. That air shroud allows us to shrink the inner diameter of the nozzle to reduce nitrogen consumption and helps guide the nitrogen through the kerf.”
A low-pressure air compressor is typically used to supply air to the AGR-N2 nozzles, Conroy says.
The next logical step in the evolution of the technology was “to combine the benefits of mixed gas with the features of the AGR.” Mix gas is a blend comprising about 95 percent nitrogen and 5 percent oxygen. The resulting advancement was dubbed and patented AGR-MIX—a nozzle that has a similar structure to the AGR, with nitrogen being funneled to the center of the nozzle in an air shroud. “There’s a separate chamber that funnels some of that air into the stream of nitrogen, creating a mix gas just like with a blending tank” without the actual tank or high-pressure oxygen, Conroy explains.
He says the nozzle also features a “no-contact” technology, sitting above the surface of the material, which means the nozzles last longer and foster more stable processing.
BENEFITS
The blended gas in the AGR-MIX can minimize the burr on carbon steel, as well as reduce assist gas consumption significantly. On its own, the AGR nozzle technology can reduce nitrogen assist gas consumption by up to 75 percent, and combining it with mix gas can provide additional savings.
Choosing among the AGR options depends on part requirements. “Anytime you’re using an assist gas that contains oxygen, there will be some amount of oxide on the part,” notes Conroy. “For some customers, that presents concerns for downstream processes such as painting. AGR-N2 is 100 percent oxide-free processing. If customers need pure cut parts, no oxide, that’s going to be the best option for a cost-effective solution. The AGR-MIX will have some oxide on the cut surface but provides burr reduction over normal nitrogen cutting if oxide can be accepted.”
Customers who have been using AGR-MIX have been processing “tons and tons of material a day with perfect stability and excellent cut quality,” says Conroy, in addition to taking advantage of the wider kerf that mix gas provides. This makes parts easier to remove from skeletons, “especially thick material” whether it is removed manually by operators or via automated sorting systems.
BEST OF BOTH WORLDS
The AGR technologies are featured on Mitsubishi’s GX-F Advanced Series of artificial intelligence– enabled fiber lasers. The machines’ intuitive AI technologies make them easy to use for operators of all skill levels and can enable smoother lights-out production.
“The AI analysis monitor that ties into these nozzles is able to track the conditions of the nozzle over time,” Conroy explains. “If they were to get damaged in production, the machine is able to stop and correct that, changing the nozzle out independently and preventing production of bad parts.”
Mitsubishi’s GX-F Advanced Series has a microphone and a light sensor located inside of the cutting head that listens to and watches the cutting process in real-time, assigning a cut rating anywhere from zero to 100 percent and using this rating to adjust the cutting condition for better or more efficient processing. AI nozzle monitoring builds on this tracking with a camera installed inside the nozzle changer to facilitate switchover without operator intervention.
The AGR-MIX nozzle combines low-pressure air and nitrogen inside the nozzle, creating a perfect, adjustable blend.
A lot of our customers are actually running lights-out, and there’s no operator to correct problems, so the machine is monitoring the cut in real time. If it detects abnormalities, it begins its checks, and one of the first things it checks after detecting an error is that the nozzle is in good condition. It takes a picture of the nozzle, then uses an AI algorithm to determine the quality and the expected life of that nozzle. If the nozzle is bad, it will automatically change it out if there’s one in better condition, and then reprocess. If it determines the nozzle was, in fact, good, it goes back to the cut and makes adjustments to the condition to try to fix the issue.”
HOW IT WORKS
AGR-MIX NOZZLE
AGR-MIX is able to combine gases without the use of external blending tanks. The GX-F Advanced Series is one of the only machines on the market that can run two assist gas types at the same time, “We’re using low-pressure air,” says Conroy. “The dedicated compressor not only supplies the air to the AGR-MIX nozzle, but we use it for the AGR-N2 and the low-pressure air cutting, as well, which is 100 percent air cutting and [serves as] the most cost-effective solution for many applications.”
He says the AGR-MIX is providing users with the “best of both worlds” in gas reduction and better part quality. In addition, for shops that run a wide range of materials, the AGR-MIX nozzle can adjust the gas composition “just by changing the conditions. You don’t have to change any valves or adjust any dials. It’s all automatically controlled.”
MC Machinery Systems Inc., mcmachinery.com
