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Lou Kren Lou Kren
Senior Editor

Titanium Laser Cutting—Don't Sweat It

January 21, 2021


Titanium sheet, as hard as steel at nearly half the weight, certainly provides challenges when shaping it into a quality part via stamping, bending or punching. It demands care in processing, especially given its high cost. Mistakes with titanium most assuredly can derail the profit margin on a job. It’s a bit surprising then, that fabricators can laser cut titanium sheet with relative ease. 

Parts produced from titanium sheet can be found in chemical-processing applications such as for tanks and other equipment, and in aerospace for wings and turbine parts. Flexibility and durability at a light weight make titanium the material of choice here. We just don’t hear so much about titanium-sheet work due to the confidentiality agreements often encountered in aerospace and defense projects. But the work is out there for fab shops.
“From a cutting perspective, titanium isn’t terribly unique,” offers Brett Thompson, TruLaser technologies and sales consultant manager for Trumpf North America. “From a bending perspective it certainly is, again due to its massive memory.”

We’ll save titanium bending for another day.

Similar to Cutting Stainless

Laser cutting titanium offers similarities to cutting stainliness steel.

“Titanium sheet behaves very similarly to stainless steel,” Thompson says, with a caveat related to edge quality. “When using nitrogen assist gas, cutting edges will bronze a bit. Using nitrogen will provide a cut edge not quite as smooth as when using argon.

“But when working with, say, 2-mm-thick titanium,” he continues, “refer to a 2-mm nitrogen technology table developed for stainless steel. It’ll be pretty darn close. For a much thicker sheet of titanium, perhaps an oxygen cut is the way to go. With any of the laser cutting machines that Trump sells, for example, a fabricator can cut thin titanium sheet with nitrogen using those stainless-steel tech tables.”

Should quality be of added concern, a fabricator can elect to use more-expensive argon as an assist gas.

Consider Sheet Size

Working with an expensive material like titanium demands that fabricators consider sheet size.

“The cost of titanium will make you handle it a little bit differently,” Thompson says. “When laser cutting, material utilization always is, or should be, a key consideration. We always want to get the most out of that piece of material, and with titanium, downstream processes can play a factor.”

In particular, bending operations farther along in the process should be considered.

“A fabricator may have, say, a grain restriction for bending—a lot of shape memory in the material can make repeatable bending problematic,” says Thompson. “With grain-restricted materials, a fabricator should consider bending accuracy down the line. That could mean consideration as to the sheet sizes to use. If all of the parts must be cut in the same orientation due to that grain restriction, perhaps a 3 by 10-ft. sheet will offer better material utilization than a 5 by 10-ft. sheet.”

Argon Use May Up Production Cost

As far as any energy-usage or machine-maintenance considerations, cutting titanium sheet should be similar to that for mild or stainless steel.
“The energy is a constant, so a machine will consume X number of kW/hr.,” Thompson says. “Cutting a bit slower on titanium than on stainless steel—and I’m not sure slower speed is needed—means higher energy consumption per part. Switching to argon as the assist gas rather than nitrogen definitely adds cost as argon is relatively expensive. With no appreciable difference in maintenance costs, argon will be the driver for higher costs when cutting titanium if a fabricator desires that higher-quality cut.”

Should fabricators want machine options to optimize titanium work, machine manufacturers do offer packages. Trumpf, as Thompson points out, provides a straightforward approach.

“Our standard laser cutting machine automatically switches back and forth between assist gasses,” he explains. “Suppose that a fabricator cuts two types of alloys with five different sheet thicknesses. Upon loading, the machine automatically selects the assist gas and its pressure according to the material used—inputs for high-pressure nitrogen, low-pressure oxygen and low-pressure compressed air. A titanium package provides a fourth high-pressure input, where a fabricator can plug in a bulk-argon supply.” 

The technology tables, essentially governing laser behavior, then can select the needed supply.

“Cutting with argon, the laser knows that it has to access that fourth input for the high-pressure argon,” Thompson says. “A titanium package provides an additional assist-gas port on the machine, with additional data included in the machine control.” MF

Industry-Related Terms: Edge, LASER, Material Utilization, Stainless Steel, Alloys, Bending
View Glossary of Metalforming Terms

 

See also: TRUMPF Inc.

Technologies: Cutting

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