Since being heralded by the respected The Economist magazine as the “next industrial revolution” a little more than a decade ago, it can be argued that additive manufacturing has failed to live up to the promise and hype of a true disruptive technology.
The benefits of additive manufacturing, or 3D printing as it’s often referred to in the mainstream media, are evident: The process of layering and bonding material to create an object straight from a 3D design creates the advantage of combining what would otherwise require multiple pieces into a single part. In turn, this leads to much greater design freedom, affordable customization, weight savings and simplification of assembly. But at the same time, the high cost and slow production of additive manufacturing technology has meant that it could only reach significant adoption in the medical, dental and jewelry industries, where mass customization and design flexibility reign as key drivers and small parts printed from plastics or composites is desired.
For most industrial metalworking applications, additive manufacturing has not fully matured beyond its use as an effective prototyping technology to large-scale production of end user parts. This has been markedly true in the aerospace sector, where part consistency is critical, and in the automotive sector, where cost and speed are key to profitability. The slow adoption in these sectors has been despite the fact both thirst for the lower weight components that additive manufacturing makes possible.
That may soon be about to change, however, and Canadian shops serving the aerospace and automotive sectors would be wise to take notice. The time to consider serious investments in additive manufacturing capabilities will soon be upon us. Already all major OEMs have additive manufacturing divisions and are testing additive manufacturing solutions in complex designs.
Over the next five years, SmarTech and General Electric forecast the global AM market to reach $US 5.4 billion. Consulting group IDC Canada expects the number of production-oriented additive manufacturing solutions in the field worldwide to grow 25 per cent a year till 2025.
What’s driving the increased investment in additive manufacturing from the industrial sector? Certainly, there have been innovations in the machinery, including improved controls and process monitoring, increased power, parallel processing, and automated material handling. The 2019 Wohler’s report on the additive manufacturing industry identified more than 30 manufacturers offering well over 100 models of metal additive manufacturing equipment. The maturing of production techniques such as binder jetting technology and wire arc additive manufacturing is also important. More on those later, but first let’s examine how one of the most basic of changes can have the largest of impacts. It’s a story with an important Canadian connection.
Aluminum alloys have a high strength-to-weight ratio, which, as already mentioned, is a critical factor in the automotive and aerospace industries. Yet although a growing percentage of automotive and aerospace parts are made with aluminum, the use of aluminum in additive manufacturing, especially for production of end user parts, has been limited by the performance of the aluminum powders available today, says Tim Greene, research director with IDC Canada. Powder Bed Fusion, currently the dominant additive manufacturing process in the industry, is highly dependent on the process consistency of the feedstock to produce reliable parts. The aluminum powders used for additive manufacturing, however, were developed for use in traditional manufacturing processes rather than being specifically designed for additive manufacturing. Uneven shapes and sizes in the powders and high levels of oxides create inconsistencies in the additive manufacturing process which can impact the strength of the finished parts. Manufacturers are thus compelled to increase the design margin in the parts they produce and reduce production speed to counteract the negative effects of these inconsistencies.
“How can we increase the reliability and reproducibility of the parts that we are actually manufacturing? This to me is a big issue, to reassure all the final users of those additive manufactured parts that the parts will sustain both the life and the performance that we are looking into,” says Dr. Mathieu Brochu, a professor at McGill University who conducts research in the field of metal additive manufacturing.
Ensuring better consistency and speed for metal additive manufacturing is where the Canadian connection comes in. Ottawa-based Equispheres is a manufacturer of patent-pending aluminum powders, aimed at the automotive, aerospace and defense industries. Its powders are produced by an atomization process it says creates uniform spherical particles with characteristics specifically suited to the additive manufacturing process.
“On the feedstock side, we need improved melting behaviour, reduced layer variability and reduced contamination. So we want feedstock that is going to allow us to really push the boundaries without starting to see instability in the melt and defects growing as we push faster,” says Evan Butler-Jones, director of applications engineering, at Equispheres. “How that flows together is that these properties of the powder, such as sphericity, smoothness, uniform size, free of fine, and low oxygen content in the powder itself, what that leads to in the processing is improved flowability, which leads to greater spread density, more even spread, less moisture adsorption, so you’re getting less hydrogen-oxygen contamination in the powder, and better chemical stability. And when you combine all those things, what that means is that we get a very consistent melting and solidification behaviour… Because we can do that we are able to get very high increases in production speed or we can get lighter but stronger parts, built more consistently and quickly.”
Recent testing conducted with additive equipment manufacturer Aconity3D, using its AconityMINI printer, demonstrated Equispheres’ feedstock can print three times faster than traditional powders and achieve part cost reductions of 50 per cent, according to both Equispheres and Aconity3D.
The part printed, designed by Aconity3D specifically for additive manufacturing, was the Aconity SCAN, a core component of the company’s machinery optical set up.
“The part integrated water and pressurized air channels for cooling the electronics that are mounted at a later stage. Only with additive manufacturing is it possible to build these cooling channels in such an effective way,” said Martin Buscher, head of testing facilities, Aconity3D. “What we did next to further increase our processing of the part is that we built the part onto a base plate and then additively built up the part. The base plate then can be remounted onto a milling machine and we have a reference position for the post processing of all the surfaces.”
At the start of this year, the Federal Economic Development Agency for Southern Ontario announced it was providing Equispheres with a $3.5 million repayable contribution to help it accelerate production of its metal powder materials. Equispheres is bringing online additional high-speed commercial reactors to manufacture its aluminum powders.
“Equispheres aims to enable industrial 3D printing to compete with traditional manufacturing. Our metal powder technology dramatically reduces the cost of 3D part production such that it is economically viable in volume manufacturing applications such as automotive,” says the company’s CEO, Kevin Nicholds.
The other major development showing potential to turn additive manufacturing into a high-volume manufacturing process for metalworking is the maturing of equipment technology. The development of production-oriented binder jetting additive manufacturing systems has the potential to deliver much greater production speeds than laser-based systems, says IDC Canada’s Greene, adding that compatibility of enhanced feedstocks such as the ones developed by Equispheres with binder jetting solutions will produce even more gains.
Binder-jetting solutions use inkjet print head technology, ejecting millions or even billions of chemical binder out of a print head onto a spread layer. Some binder-jetting technology vendors are promising production speeds up to 100 times faster than with leading power-bed fusion systems, Greene points out in a white paper he has authored. Another benefit of binder jetting is the ability for stacking parts to increase production speed. Binder jetting technology makes it possible to stack multiple layers of parts on top of each other in the build box, nesting them within all three dimensions of the printer’s build volume. This makes it possible to manufacture multiple parts at the same time.
At the other end of the production spectrum are developments with wire arc additive manufacturing. Until recently, this technology had been limited to plastics and smaller-sized parts made with metal powders. However, recent breakthroughs are facilitating new ways to overcome common challenges associated with the production of large metal components for a variety of industries such as aerospace, automotive, oil and gas, and construction and mining.
Wire arc additive manufacturing combines gas metal arc welding (GMAW) with sophisticated automation, explains Mark Douglass, business development manager with Lincoln Electric Additive Solutions. The process involves the use of 3D CAD software and the application of a robotic arm with a GMAW torch, which puts down successive layers of melted wire feedstock onto a multi-axis positioner to form a single, fully formed part. The process is ideal for parts larger than a basketball and can be readily scaled to several metres.
“By utilizing additive manufacturing, what would normally take months to produce a casting or forging can be reduced to weeks. This significantly reduces lead times for prototypes and finished products,” Douglass states in a white paper he authored. “In one case involving the production of a mould tool for aerospace composites, the application of additive manufacturing was found to shorten delivery times by as much as 60 per cent compared to traditional manufacturing.”
The combination of layered manufacturing and flexible automation also makes for much greater design freedom when it comes to complex geometries. For example, complicated, multipart structures can be reduced to a single part, saving time and the nowadays risky requirement to source parts from multiple vendors. There is a Canadian connection here as well.
While using its 3D printing technology improved lead times, the size of the parts it was dealing with – including a hollow blade propeller five feet in diameter and large automotive stamping dies and moulds — and the complexity of some of the designs created measurement challenges.
“The fact that we were going to make very large parts, measuring in feet and weighing sometimes thousands of pounds, meant that a coordinate measurement machine was not going to cut it,” Douglass says.
So the Euclid, OH company, which was launched mid-2019 by well-known industry parent Lincoln, looked at alternatives. It decided 3D scanning fit the bill because the technology could provide a full 3D surface model of the part in question. That model could then be compared to the original CAD model. The company eventually settled on Levis, Quebec’s Creaform and its hand-held MetraSCAN 3D technology. Creaform’s MetraSCAN 3D features 15 laser crosses making it capable of tackling large scanning areas. It has a measurement rate of 1,800,000 measurements per second.
“It is very fast. We can measure our parts in a manner of minutes,” says Douglass, adding that MetraSCAN’s easy portability addresses Lincoln’s need to take the measurement tool to the part since its parts are large and heavy to move.
Speed, accuracy, reliability: When additive manufacturing and its supporting technologies are capable of consistently delivering on all three of these attributes, their acceptance among Canadian jobs shops serving the lucrative aerospace and automotive sectors is sure to add up. SMT