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Lasers Enhance Traditional Machining

By Larry Adams Contributing Writer, SME Media

Next-generation CNC machines combine traditional machining with laser cutting, welding, and additive manufacturing.

An Okuma laser unit performing case hardening. (Provided by Okuma America)

Metalworking machines are fast, powerful, and accurate, but they weren’t always as capable as they are today. Modern equipment is more nimble, flexible and adaptable. The machines collectively exceed the sum of their parts. They feature live tooling, multiple spindles, tool turrets, and multiaxis capabilities. They turn and mill, drill and tap, bore and ream and they do so repeatedly, quickly and efficiently.

They have evolved. They continue to evolve. Adding laser technology is just the latest of these evolutionary trends.

Known by some as multitasking machines, and by others as hybrid machines, these devices feature laser technology, traditional metalworking equipment, and sometimes additive manufacturing in one. They can mill metal by traditional means and then laser cut, laser weld, perform repairs, and clad materials.

One machine can do the work of many. One clamping means more process predictability. It may help lower costs per part.

“Multitasking machines have become more important because of their ability to make a complete part in one shot, and to minimize the time to go from job-to-job,” said David Fischer, lathe product specialist and hybrid machine expert for Okuma America Corp., Charlotte, N.C. “These machines give us a lot of production flexibility.”

New to the Market

Several suppliers have joined the multitasking market. Additions to the laser/traditional cutting machine genus include Okuma, with its LaserEx products, Tsugami/REM Sales with its integrated lasers in its LaserSwiss models, and Marubeni Citizen-Cincom Inc. with the Laser System L2000.

For example, Okuma has increased its R&D efforts in recent years and one result is what the company calls “super multitasking machines.”

“Okuma is more than 100 years old, and for most of that time all we did was remove material,” said Fischer. “As of 2017, we can now add material. That is a big change. Where is that change going to take us in the next 100 years?”

The LaserEx technology is available on certain of the company’s MU series of machining centers and some of its Multus CNC lathes. One of the newest models is the MU-8000V five-axis vertical machining center that integrates the laser metal deposition (LMD) technology.

Operators using this equipment can move between additive and subtractive processes as needed. Parts can be repaired and inspected throughout production, and an infinitely variable control of laser spot diameters of 0.4 to 8.5 mm increases efficiency and resolution. Parts built with additive methods might need milling to finish the part. Or, additive technology might be needed to repair parts that have developed flaws such as cracks. All can be done on the machine.

LMD bonds metal powders to a substrate. A laser beam heats up the parent material’s surface and creates a weld pool. Fine metal powders are spread evenly into the weld pool via a nozzle, where it melts and combines with the base material. A layer is approximately 0.2-1 mm. Additional layers can be deposited onto the surface if required.

The system uses a disc-type laser from Trumpf, and operators have complete control over the power range generated by this diode-pumped, solid-state laser. The laser can be adjusted on-the-fly from 200 W up to 4 kW.

Different metal mixtures can be created to achieve different metal parameters. For instance, Okuma has worked with a stainless steel and Inconel mix. This recipe provided the benefits of stainless steel with Inconel, an expensive material that has a high tolerance for extreme heat while maintaining tensile strength.

Fischer said that combining technologies, processes, and material mixes promises to result in future part design opportunities. “Creative people will love this,” he said. “It is going to be a very exciting future.”

Swiss Machines Get Lasers

The L2000 features through-coolant capability and can incorporate an auto load bar feed system for continuous production. (Provided by Marubeni Citizen-Cincom)

Swiss-style machines are already some of the most flexible technologies on the market. The machines create complex parts by performing many operations in an optimized fashion. Marubeni Citizen-Cincom Inc., Allendale, N.J., has added laser cutting and welding to its arsenal with the addition of the Laser System L2000. The system can be incorporated with a range of Marubeni Swiss machines and with the addition of an autoloading bar feed system can achieve nearly continuous part production runs.

The L2000 features a 10-µm fiber optic system that is interfaced to the machine control for easy programming. Cutting paths and offsets, for example, are fully controlled and edited. The company uses an IPG Photonics 400 W single-mode laser unit. Also available is the Quasi Continuous Wave 300 W system that can provide a power burst to 3 kW.

“We had many customers creating parts with our Swiss machines that had to go to a secondary process to do laser cutting for different shapes,” said Randy Nickerson, laser product manager. “The idea of Swiss [processing] is to try and do everything in one place so this was a natural fit. Over the years, it was the dream to combine a laser into the machine. Eventually, the technology was available so that we could actually do it.”

The laser head can mount on the gang tool side of the machine and its movements programmed in the part program of machine control. The unit can also mount on the B axis for cutting at various angles and achieving angular laser cut features.

One advantage of the laser is its ability to repair flaws in the part. “If the laser cut doesn’t come out perfectly clean, which can happen when cutting thicker parts, we can go back in and clean it up,” Nickerson said.

The fiber laser can be adjusted to achieve a sharp focus to create fine features. “The smaller the beam going through the part, the sharper the corner,” Nickerson said. In addition, many part features could be damaged by traditional machining, “but the laser beam doesn’t break them because it does not actually touch anything physically.”

Creating these small features can cause HAZ (heat-affected zone) problems and small chip buildup. For both issues, Nickerson said that through-coolant technology is the answer. The metalworking fluid minimizes heat and flushes small particles.

Meeting Customers’ Needs

Tsugami/Rem Sales, LLC, Windsor, Conn., also added laser technology to its Swiss-style machines, including the SS207-5AX LaserSwiss model. That model is a 20 mm, seven-axis CNC Swiss lathe with two fully integrated SPI lasers, one for cutting and one for welding. It can hold up to 33 tools. The machine is part of the company’s Laser-Swiss product line and is the first to include a second laser head for welding.

Tsugami offers an integrated laser in its LaserSwiss models to perform laser welding. The two lasers in this machine are on the right, with copper-colored nozzles, at top and bottom. (Provided by Tsugami/Rem Sales)

“We integrated the lasers because we saw a need to streamline operations [in shops] with Swiss machines and laser cutters. It made sense to combine the operations into one,” said Daniel Walker, director of business development.

The laser heads were designed in-house by Dale White, the company’s automation and laser product manager. “When we came into the process, we were using off-the-shelf equipment,” said White. “We developed something that fits our niche and gets the best cuts possible on a platform that has technologies blended together.”

Doing the design in-house, White said, gives the company a lot of flexibility when it comes to serving its customers. The company’s LaserSwiss machine models include a variety of machines that can turn, thread, tap, mill, gun drill, or thread whirl when the laser isn’t in use. The machine’s original tooling is practically unchanged. The equipment ranges from 12 to 32 mm and features three to seven axes. Some models feature a B axis, on which a laser can be mounted, and a second laser head for welding. Power supplies range from 200 to 500 W. Laser power, frequency, pulse width, gas pressure threshold and lens focus are on-the-fly adjustable from the machine’s FANUC control and response time is less than 10 ms.

Through-part coolant is a key feature for both Swiss machining and laser cutting. Tsugami’s customers are producing small parts and each small part poses a challenge, said White. “The smaller the part, the more challenging they tend to be. You start getting into things that are under 1/16″ (1.58 mm) in OD, then you have to start worrying about back-wall striking and cutting in places where you wouldn’t want to cut.”

Back-wall striking means that a laser will cut through metal and ram an opposite surface or reflect back against a surface. The coolant protects against this problem by breaking up the beam as it tries to pass through the work zone.

Fixing part flaws can also be accomplished with this system’s laser welding capabilities. The addition of laser welding came about by a customer request, said Walker, after some roll-formed parts developed stress cracks that were not acceptable in the final part. The laser welding re-flows the metal to repair the cracks.

This is an example of listening to customers and is one of the keys to expanding capabilities and, ultimately, projects, according to Walker. “We’ve found out from our customers that after they purchase the machine, our customers’ customers begin to design parts around them.”

Customers Drive Laser Cutter Development

An Epilog laser cutter creates a unique part made from acrylic and gives it a flame-polished edge. The technology can cut any shape that can be created on a computer screen. (Provided by Epilog)

Listening to and meeting the needs of the customer is just good business. For Epilog Lasers, a Golden, Colo., company known for its etching and marking laser technology, customers wanted to laser cut. The company listened.

Now Epilog has laser cutters in its portfolio. The CO2 laser cutters can cut soft materials such as wood, paper, plastic (acrylics), fabric and foam, and do so repeatedly with accuracy down to the thousandths.

Epilog’s lasers systems are meant to be as easy to use as a paper printer. Designs are created in programs such as Adobe Illustrator, Corel Draw, AutoCAD, and Solid-Works and these files can be printed directly to the laser cutting machine, said Mike Dean, vice president of sales and marketing.

Epilog’s high-speed CO2 laser machines come in a variety of configurations. The CO2 lasers are available in a power range of 30 to 120 W, have a work area of approximately 16 x 12″ (406 x 305 mm) up to 40 x 28″ (1,016 x 711 mm), and have a maximum material height of 4.5″ (114 mm) to 13.25″ (337 mm).

New capabilities are on the horizon. “We started out with an 11 x 11″ (279.4 x 279.4 mm) work area; now we are developing a 48 x 36″ (1,219 x 914 mm) machine in our Fusion line,” explained Dean.

Epilog developed the vector cutting technology after a research and development project. “R&D was a large effort because of the two modes; raster mode (or engraving mode) is entirely different than vector mode,” says Dean.

In raster mode, engraving occurs one line at a time. “Think dot matrix printers that spit out one line of data at a time and then they spit out another line, and the image builds as the paper moves,” explained Dean. “Vector cutting is following the profile of a line or a curve. In vector cutting mode, you turn the laser on and the carriage moves; the laser stays on constantly and penetrates the material that you are working with and cuts all the way through the material you are cutting.”

The company offers a range of products designed for use at the professional level down to the DIY, hobbyist, and artistic markets, and machines that have multiple capabilities, Dean said. Epilog will continue to look for ways to satisfy its customers’ needs. While those needs may change, some things are tried and true. “What is interesting is that the basics of the machine have not changed that much,” he said. “What has changed is the speed and the size of the machines. But we also see a market for a less expensive machine.

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