Machine makers are swiftly moving from metal to more novel composites and alloys. To evolve accordingly, the metalworking fluids industry needs to turn first to academia to better understand how to work with these materials, and then to collaborations that will help commercialize products- and fast. That was the message delivered by one the worlds four biggest petroleum additive suppliers, Afton Chemical Ltd., at this years Uniti Mineral Oil Technology Congress.

Change is sweeping the industry, Marketing Technical Specialist Steve Griffiths told the April meeting in Stuttgart, Germany. Big global industrialists (think General Motors, Boeing and Rolls-Royce) are replacing traditional building blocks like aluminum and sheet metal with new heat-resistant titanium alloys, composites, hard-coated components, 3-D printed materials and polymers.

The advantage of the shift is obvious, Griffiths said. Aerospace and automotive engineers are continually under pressure to reduce weight and increase strength, and the new materials accomplish both goals.

Airbus A350 models, for example, are now composed of around 53 percent composite material by weight. The switch results in annual savings of more than U.S. $100 per kilogram of material for each airframe.

Boeings shift to composites achieved success in another way. An older 747 model needed approximately 1 million fasteners to hold its frame together. In contrast, the composite-based components used to make shells of Boeing 787 aircraft can be primarily bonded – or glued – together, and require less than 10,000 fasteners, making the plane more aerodynamic and more efficient.

Its All Material

The benefits of alloys and composites extend beyond aerospace markets to automobile manufacturing and various petroleum industrial markets, as well – particularly in extremely high-temperature operations. Heat-resistant super alloys and silicon-infused ceramic materials and ceramic matrix composites, for example, not only reduce weight but also are able to withstand much higher temperatures than metals can, Griffiths noted.

The hotter an engine burns, the more efficient it is, but engines are limited by how much heat their component materials can handle, he explained. The predominant technology of most aircraft engines currently features metal-based alloys in the hot end of turbines. Next-generation engines will use silicone-infused composites instead.

The migration has been dramatic in the automotive and aerospace industries over the last 10 to 15 years, to the point that composite has become a buzzword, he continued. Yet many of these novel material technologies are not fully mature, especially in the case of ceramic matrix composites and 3D-printed materials.

The inevitable shift from what is termed general machining is right around the corner, though. Afton expects a 1,000 percent increase in the use of ceramic matrix composites by 2024, for example.

The two companies widely considered to be the worlds leaders in automotive and aerospace industries – GM and Rolls-Royce – are finding that composites offer the best and possibly only way to achieve the fuel-savings needed for next-generation air systems currently in the works, he pointed out. However, each new material poses specific challenges to the metalworking fluids industry – both in terms of formulating new products with specialized additive packages, and in the actual cutting fluid and coolant application processes.

New titanium alloys, aluminum alloys, ceramics and other types of novel materials mentioned are very different than the traditional metals the industry is used to, and they are all very sensitive, he pointed out. Yet [manufacturers] expect that [metalworkers] will be able to machine and manipulate and manufacture these materials cost effectively – if not at the same cost – in exactly the same way, all while preserving finish and aesthetics.

Whats the Issue?

The most common composites today are organic matrixes such as carbon-fiber reinforced polymers, he continued, which offer everything a manufacturer needs: They are lightweight, very strong, and generally workable.

But, he asked rhetorically, what type of metalworking fluids work with these materials? After all, they are not metal. The need for new formulations is inevitable, he said, but blenders and additive suppliers must find out exactly what it takes to manipulate and cut these materials, and quickly.

Some problems are already apparent. First, components made from the new materials are larger and more complex, Griffiths said. Plus, instead of being fastened together, composites are essentially glued together, which presents a potential problem for cutting and manipulating.

Many composites are also porous, meaning the lubricant will permeate the surface. Its not clear how that will affect the performance of either the fluids or the material, and whether there are efficient and acceptable removal methods for when this happens.

Manufacturers of new hard-coated or lacquered materials are as concerned about cosmetics as they are about structural integrity. Its easy to damage and contaminate the coatings, Griffiths pointed out. Coolant contamination can cause corrosion, and heat damage can lead to fatigue cracking and failure.

With materials in some machining processes potentially spinning at 30,000 revolutions per minute, the potential for a disaster is quite high. [The metalworking fluids industry] has to make sure these things dont happen.

Literally thousands of new titanium and aluminum alloys are being developed daily, Griffiths said, but all types of aluminum are susceptible to corrosion and staining, and all types of titanium have difficultly transmitting heat.

3D printing – known more commonly in industrial circles as additive manufacturing – brings another set of challenges for metalworking fluid providers. Media coverage suggests that 3D printing will revolutionize the manufacturing industry, he noted. Companies like DMG Mori Seiki and others have developed new machine tools that actually cut and 3D-manufacture at the same time – reducing weight by producing components that are far too complex to produce by forging or cutting from solid metal.

Yet, while 3D printing might reduce the amount of general machining, it will certainly not eliminate it, Griffiths insisted. So rather than lament that additive manufacturing will mean fewer customers for metalworking fluids, the industry should focus on the 3D-printed applications that still need fine-tuning and cutting.

Additive manufactured materials are sintered through power metallurgy and fused together by laser or high-energy processes, he said. What we dont know is how that material will act when its being cut.

Changing Conditions

Metalworking fluid formulations arent the only part of the industry that will change in light of advanced materials – other parts of the physical machining process are already being tweaked.

For example, hard-coated materials, similar to ceramic composites, generate debris. In neither case is it particularly clear how lubricants will react to a more abrasive cutting area. Workarounds – such as inducing vibration to help clear the surface of powdery chips and swarf while cutting – may be necessary.

In the never-ending quest to improve component quality; reduce cycle times; reduce costs through reducing consumables; reduce the amount of tooling time and power; reduce and manage scraps; and improve maintenance of machine tools, there are many advanced manufacturing centers now that actually improve on the overall process by taking every micro-step possible. One such center was able to shrink a 92-hour machining process for a particular Rolls Royce engine to a less than 9 hours. Coolants and lubricants need to perform even better to keep pace, he said.

Coolant pressure is another prominent area of focus that has a direct effect on metalworking fluids providers. Standard high-pressure is up to 80 bar of pressure delivery, he noted. Ultra-high-pressure, which is becoming more and more prevalent, is anything above 80 bar – up to 250 or 300 bar.

Upping the pressure helps improve tool life and preserve these new types of materials – especially titanium, he explained. Take the same material under the same conditions for the same period of time – one tool will be damaged beyond use and the other will still be in its prime, and thats just from changing the coolant pressure.

At a higher pressure, coolants can be delivered to exactly the right place. When you think about titanium, thats exactly what [the industry] needs. But with coolants being applied at pressures into the hundreds of bar, suddenly foaming and coolant breakdown become real issues, he noted.

Foaming is always potentially an issue, but breakdown -shearing of components within the coolant – is of huge importance, when now [the industry] is starting to work at pressures that could potentially cause [shearing]. Yet, adding an increased dosage of defoaming agents is not an easy solution, he noted, because they can have a negative impact on performance.

Machine tool design is also changing along with the adoption of new materials, he continued. Flexible multitools and grease-filled linear guide rails are replacing things like traditional slideways and production lines, especially in automotive manufacturing. These tools reduce machine size and, thereby, the size of the fluid sump. And extra filtration needs to be added to maintain coolant condition. Both downsizing and added filtration put more pressure on the cutting fluid, he noted.

In light of these changes, the industry recognizes more than ever that manufacturing fluids and cutting fluids can no longer be ignored, he said. They are now considered to be as important to the machining process as the cutting tool and the material.

Then Theres theGovernment

To keep up with changing materials, suppliers also need to navigate a changing regulatory environment, which Griffiths said has the industry more uncertain than ever. Suppliers must pay perhaps the most urgent attention to the process necessary to expedite new metalworking fluids from the research and development phase through to commercialization, he concluded.

Because these materials are novel, a significant amount of research is taking place. Can you imagine the number of metalworking fluids out there, all with different formulations? Research to find out how every single one of those will affect every single one of these new types of materials is necessary.

Using NASAs nine-step Technology Readiness Level scale, Griffiths pointed out that levels one through three (basic research and development) are currently taking place in academia. Levels seven through nine (demonstrating, proving and finally adopting new technology) are areas where the industry is fully competent.

Griffiths stressed that theres a gap in levels four through six that needs to be bridged to bring metalworking fluids for these new applications to fruition. Industry professionals and universities need to collaborate to meet in the middle and deliver what we need next. He said that the industry needs more support like it is getting from the Advanced Manufacturing Research Centre in the United Kingdom.

Partly funded by industry and partly by the European Union, the AMRC lab validates research and produces workable prototypes to help unite universities and the marketplace. Comprised of mostly blue chip companies, AMRC has over 30 partners, including manufacturers and material suppliers. Afton is concentrated on and working in tandem with AMRC to develop next-generation additives, such as boron-free corrosion inhibitors, low-foaming polymeric emulsifiers, emulsifiers for API Group II/III base oils and novel passivators for sensitive alloys.