ETMM exclusive ‘Disrupting’ the market with a hybrid production centre

Editor: Eric Culp

Machine tool giant DMG Mori has surprised the industry with the introduction of a centre that both mills metal and adds it to a workpiece. The company showed a prototype of the unit at Euromold 2013, and we discussed the technology with its developers.

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The calm in the storm: Greg Hyatt (c.) helped put DMG Mori in the quickly expanding field of additive manufacturing.
The calm in the storm: Greg Hyatt (c.) helped put DMG Mori in the quickly expanding field of additive manufacturing.
(Source: Culp)

If you wanted a closer look at DMG Mori’s unit for additive and subtractive manufacturing at Euromold, you generally had to wait in line. The Lasertec 65 Additive Manufacturing unit, based on a DMU Monoblock machine tool, offers both the well-proven technology of milling as well as up-and-coming metal additive manufacturing through laser deposition, and it proved quite the draw. Greg Hyatt, senior vice-president and chief technical officer at DMG Mori USA and Friedemann Lell, sales director at the Sauer Lasertec unit discussed the technology, which was developed by Sauer Lasertec.

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ETMM: You've talked about this machine as an example of a “disruptive technology”.

Hyatt: A professor at Harvard Business School (Clayton M. Christensen) defines this as something that compels the customer to buy completely different solutions from completely different suppliers. One of his examples was the automobile, which was not a disruptive technology as it was initially so expensive that it had no impact on the demand for horse-drawn vehicles. However the introduction of the mass-produced automobile was disruptive. Henry Ford’s Model T devastated the traditional suppliers of horse-drawn wagons. It is important to recognize that it is always the new value-proposition to the customer which powers the disruption, not just the technology. Our hybrid is a perfect example. We did not invent the automobile, or in this case the laser or the milling spindle, but we are combining existing technologies to provide new value propositions and to enable new business plans, like the mass-produced automobile.

Lell: In our case it's not exactly what you would call a “disruptive technology” but rather the intelligent combination of existing technologies.

ETMM: What kind of technologies used today do you think this type of production method could replace?

Lell: For us, there are three main areas of application. First of all, the production of workpieces featuring complex 3D geometries and undercuts in small to medium-sized batches. Second, repair work. And third, the deposition of wear-resistant coatings. Combining the flexibility offered by additive technologies with the productivity, accuracy and surface qualities of 5-axis milling adds value to manufacturing processes. Manufacturers of integral components or other lightweight components as well as repair shops for turbine or tool and die components will benefit from this technology.

ETMM: This is your company’s first move into additive manufacturing. Was the decision driven by expectations that this technology will be disruptive?

Hyatt: We saw technologies that we could integrate into our machines that we thought would be absolutely compelling for our customers.

ETMM: Do you have an example of this?

Hyatt: Our customers can now pursue business plans in which they differentiate themselves with rapid delivery or time to market rather than price. With a deposition rate of up to 3.5 kg/h, this process is up to 20 times faster than the laser generation of parts in a powder bed. They can realise their parts for their customers in a small fraction of the time traditionally required.

Lell: Additive manufacturing processes can help companies to produce new and innovative products more quickly. In contrast to laser melting in a powder bed, laser deposition welding enables large parts to be manufactured using a metal powder nozzle. The combination with milling opens up completely new applications. The component can be built up in several steps, whereby milling can be interspersed with deposition welding in order to allow areas, which the cutter would no longer be able to reach when the component was finished due to the component geometry, to be machined to final accuracy.

ETMM: We recently visited one of the leading powder bed suppliers, and they had some pretty big units.

Hyatt: While the laser deposition technology is nothing new, it is a reliable and proven process, which makes it outstandingly suited for the integration into DMG Mori’s high-quality CNC machines such as the DMU, NT and NTX series. We can also integrate this process into other DMG Mori machines. In future it will be possible to produce workpieces of many sizes with our hybrid solution.

ETMM: Did any specific customer demands help your decision to move into additive manufacturing?

Hyatt: Another area we thought would be compelling was based on many of the companies being frustrated by costs driven by the slow speed of deposition. The hybrid machine combines the advantages of milling like high accuracy and surface finish with the flexibility and high build up rate of laser powder deposition.

Lell: In the case of some components, e.g., aerospace applications where parts are machined from billet, today 95% of the material is removed by milling. With additive processes material is only built up where it is needed. As result, material loss is reduced to 5%. This leads to significant raw material and cost savings.

ETMM: What other advantages does your technology have?

Hyatt: Large machines suitable for machining parts needed in the aerospace or energy sectors tend to be very expensive; so having a single large machine which can do the rough machining, the deposition and finishing on one machine is very economical for customers. In the energy, oil and gas industries, components often need to be coated with a suitable corrosion-resistant alloy such as Inconell to protect any given area. The cladding process provides protection for products such as pipes, valves, flanges and specialist fabrications used in any hostile environment. With a hybrid machine, the machining of the base material, the cladding and the final machining process can be done in one setup, which provides the benefit of cost savings, as well as a reduction in lead time.

ETMM: You’ve described this method of production as sequential process through addition and subtraction and then more of both. What advantages does this technique offer?

Lell: The Lastertec 65 Additive Manufacturing is unique in the way that it enables the design of workpieces that are purely function-optimised regardless of any restrictions found with traditional machining methods. Many components that can be produced on [the machine] don’t even exist today.

Hyatt: We can also switch materials mid-process. So, if we want a core of one alloy with a surface that is more corrosion-resistant or more wear-resistant, we can switch alloys at will through the deposition rate.

ETMM: How much will you work with buyers to develop such materials?

Hyatt: We have to leave most of this up to the user because the OEMs know exactly what material properties they need from what they are designing. We typically don’t know the stresses and conditions their components are subject to.

ETMM: It seems clear that this technology is well-suited to make conformal cooling inserts. Are there any other areas where die and mould shops might be able to apply this technology?

Hyatt: One area is to avoid having to build up the entire part by deposition. Because we have large envelope machines, we can take a big mould base or other component that has been conventionally manufactured and only deposit the areas that could not be manufactured traditionally.

ETMM: This all sounds great. What will it cost?

Lell: At this stage we are only presenting a concept study. The commercially available machine portfolio will be demonstrated at the upcoming IMTS and AMB, both taking place in September 2014. We plan to go into serial production at the same time.

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