Single-source Machining

Features - Cover Story

Okuma’s Laser EX Series combines milling, turning, and grinding with laser hardening and 3D printing in one machine.

Blade shaping makes possible deposition of metals of different types.

Since 1904, Okuma has developed machines that cut metal to create a finished part. Now, the company is broadening its approach – creating machines that can add or subtract material for precision manufacturing. With the latest “do-it-all” technologies, Okuma’s machines advance multitasking and bring unparalleled ease of use and flexibility to today’s shop floors.

The MU Laser EX multitasking machine offers milling, turning, and laser metal deposition while the MULTUS Laser EX offers turning and milling along with laser hardening and grinding or laser metal deposition.

“At Okuma, we are the one source for every major component on our machines,” explains David Fischer, lathe product specialist at Okuma. “We are known to provide our own controls, motors, and drives. With the Laser EX, we are partnering with Trumpf Inc., a recognized leader in laser technology, and want to be able to provide the customer all the pieces of the puzzle to make this work.”

One part of that puzzle is the machine’s laser. The Trumpf TruDisk laser offers flexibility across a wide power range with excellent maximum beam quality. The 4kW laser powers up to six machines, offering an advantage unique to hybrid machining where the laser may be used for just a fraction of the total machining time, resulting in lower cost and better laser utilization. This system also provides “on the fly” variable control of laser spot diameters from 0.4mm to 8.5mm which increases laser efficiency and resolution.

The disc laser design ensures a long laser lifetime and eliminates risks associated with other fiber-delivered, solid-state lasers. A plug-and-play optical fiber connection allows the use of multiple fiber diameters for optimum processing results. Power stability of <1% is achieved throughout the laser’s lifetime. Possible applications for the laser include cutting, remote welding, deep penetration welding, large-area welding, brazing, deposition, and laser hardening.

“Unlike other fiber-delivered, solid-state laser technologies, the disk laser is insensitive to back reflection, making it a robust and reliable manufacturing tool for processing even highly reflective materials such as aluminum and copper,” says Frank Geyer, product manager for additive manufacturing at Trumpf.

The laser’s power output and beam size are controlled by Okuma’s OSP-P300 control, which handles all the machine’s operations including motion control, laser control and operation, and powder feed.

Laser cladding of Inconel.

Laser metal deposition

The machine implements laser metal deposition (LMD) to form parts in a variety of shapes and sizes through a controlled process. While, in the past, Okuma machine tools have always removed materials, LMD permits additional material to be added to parts, so users can clad a functional surface or build up a structure, even on an existing 3D surface.

“This process is a mature means of manufacturing and is being used in many industries, even in aerospace,” Geyer says. “The ability to process a large variety of materials and join dissimilar materials makes it a very interesting option for users.”

With LMD, four different materials can be used simultaneously, and the user can easily switch back and forth. By the end of the process, the user can come in with cutting tools to create a very fine finish.

Due to the shield gas, controlled vacuum in machining is not required, so the part can be inspected mid-process. Other advantages LMD offers include material exchange, coolant use in the work envelope, and faster processing than powder bed fusion.

With LMD, users can also perform metal cladding. Rather than selecting expensive material with characteristics required for the finished part, less expensive base material can be used with applied customization. For instance, if one area needs corrosion resistance while a separate area requires wear resistance, appropriate materials can be applied only to those points.

Applied safety measures

To protect the machine and users from the laser and metal powders, Okuma implements several safety systems into the machine. The machine is sealed against laser emissions and contains the metal powder. Mist and dust collection is critically important, so Okuma worked with Camfil to provide units based on the specific machine envelope. Meanwhile, the Nilfisk 118 EXP vacuum cleaner uses an immersion-type system to clean inside the machine when changing over from one setup to the next, as well as cleaning up after changing out powder in the powder hoppers.

Technology of the future

“If you look back at the original Okuma machine tool up to the introduction of the Laser EX, we have always removed material,” Fischer says. “So, this is really a huge change for the industry. Now, with the same machine, we can add material. It’s the first time we have been able to do it… and that allows us to do a lot of exciting things.”

One capability the machine allows users to do is select the material they want, where they want it. Geometric freedom is also possible, which permits any necessary changes to the physical makeup of the part.

For example, a customer can switch between materials on the fly and combine materials if required. The physical make-up of the part can also be changed. The machine can lay up solid material and then, if weight requirements or thermal issues need it, can lay-up a mesh structure to reduce weight or minimize heat transfer.

The machine also excites interest in repair work. If a component is worn, whether it is a die-mold component or large engine components, the worn part can go into the machine, where the Laser EX lays up new material and re-machines the part to size to put it back into service.

“Much greater consistency is possible using the Laser EX machine. I can often apply material that’s better than what the original material was,” Fischer adds.

“We are going to be amazed about where the technology takes us,” Fischer explains. “That’s my feeling. But there are a lot of practical areas to use it right this minute, such as repair, cladding, and building features on parts that previously had been very difficult. But we can do these with much more accuracy with Laser EX.”

Although the Laser EX machine won’t be delivered to its first customer until summer 2018, it is gaining popularity among universities, along with companies that want to stay on top of the curve of this technological development.

Okuma America Corp.

Trumpf Inc.