Additive manufacturing has been one of the most talked about and anticipated breakthroughs in part making in the last 50 years. Not since the advent of computer numerical control has a new manufacturing technology been so disruptive. The transition from subtractive to additive manufacturing, however, has been slow. Multiple factors are at play, but a major one is the limited working envelope and restricted size of printed parts. A new generation of equipment promises to change this—and change the economics of additive manufacturing in the process.

For suppliers of components for commercial applications in areas such as point-of-sale retail, public transit systems and the hospitality industry, one size will not fit all—and companies that urgently need to “isolate to protect” are faced with tough choices. Injection molding requires very expensive tooling, while thermoforming and rotational molding are better, but still expensive. Fabrication from semi-finished resin stock is widely used at present, but the elimination of tooling costs is offset by high labour and raw material cost. In addition, fabricated components are generally restricted to simple geometric shapes, which can be difficult to integrate into complex structures. Even if volumes can justify technologies like injection molding, tooling takes time to develop and qualify.

Large-format additive manufacturing is a natural fit since parts can be made quickly, and from durable materials that can be cleaned and sterilized.

Frank Marangell, president of additive equipment maker BigRep America, sees the challenges triggered by the COVID-19 crisis first-hand.

“At first, the market was moving to mass customization, specialization and localization. We had several orders that came in because the company couldn't get their tooling during the beginning of the crisis.  One even bought a printer because they couldn’t get their large injection molded part out of Italy. I think supply chain challenges are going to cause things to move faster and in that direction.”

This also plays into the hands of the U.S. re-shoring movement. In the current manufacturing environment, supply chains are strained or broken and injection molds that were previously purchased in Asia won’t be arriving in American facilities anytime soon. If the pandemic settles into a pattern of seasonal infection spikes and lockdowns, global supply chains for business-critical inputs such as molds and tools may become unsustainable.

“Despite the pandemic, many industries like consumer goods, home and furniture are actually growing nicely,” says Marangell. “Even midsize companies that were succeeding with injection molding are now looking at alternatives because they can’t buy a Chinese-made mold. This is changing attitudes in European as well as U.S. companies.”

The COVID-19 pandemic has created an urgent need for big, specialized parts in the shortest time possible. From an engineering perspective, environments where close proximity is common, such as transportation, restaurants, architecture and public spaces, may require extensive retrofit to create physical barriers to social distance patrons into small, discrete groups. The redesign phase will be a ground-up rethink of how everything in society works, from ridesharing cars to movie theatres.

The crisis has cut out much of the bureaucratic overhead often seen in manufacturing. According to Marco Mattia, product owner of BigRep’s Engineered Solutions business unit, “a lot of bureaucracy is collapsing. When it’s an emergency situation, you don't need to go through a lot of hoops to develop new approaches to solve problems. The innovation is much more agile now that people realize and understand how AM works and can help reduce lead times and cut costs.”

Making jigs and fixtures using traditional manufacturing methods is timely, expensive and nearly impossible to make changes after designs are finalized. Additive manufacturing completely inverts the design for manufacturability paradigm. Instead of rendering, thinking and simulating multiple revisions to refine a part for production, it’s possible to simply print it, deploy it and see if it works. This has two advantages: one is that it is faster; the second is the ability to rapidly deploy alternative solutions while the design is perfected for eventual production use.

Another advantage large-format additive provides is in printing large quantities of smaller parts in a batch.  For example, Mattia has managed to print as many as 72 parts simultaneously.  On a smaller desktop, this would have required someone to constantly monitor the printer and remove each individual part and restart the build.  With the large-format printer, you set it and go.

“At the beginning of the pandemic, we focused mostly on face shields, masks and connectors—all small-scale objects,” Mattia continues.  “BigRep’s large-format printers not only allow you to print large parts, but a large quantity of smaller parts on one machine at the same time, unlocking even more potential for customers with our machines.”

The face shield project also highlighted another advantage of additive for PPE part making: customization.

“What we realized is that some of our clients who we donated the shields to have an issue. If one of the nurses wore a face shield, maybe the next day a colleague would pick it up and wear it. The fact that they were identical and interchangeable was not always good,” says Mattia. “So, we collaborated with Schneider to make them customizable. It was a parametric solution, a script that runs once when the user types a name. We were able to print 70 at a time, but each one was personalized.”

Personalization of PPE for medical purposes is just the tip of the iceberg. Going forward, the ability to brand protective equipment will be attractive to restaurants, salons or any retail environment with a branding opportunity. Unlike injection molding, this is a matter of code—not a mold insert—and adds little or nothing to the part cost.

Materials and Surface Finish are No Longer a Constraint

Some forms of additive manufacturing have severe limitations on the availability of materials. BigRep’s open source large-format FFF machines offer a variety of materials including ASA, ABS, Carbon reinforced PET, PLX, BVOH and PVA (for easily removable support structures), PLA and several PA grades as well as TPUs and high temperature engineering materials .

Like conventional plastic processing, commodity grades are the volume leaders, but unlike traditional molding processes, dissolvable support structures using BVOH allow the printing of delicate, fragile parts without a lot of post-processing. For medical PPE purposes, several material options can support impact resistance requirements such as sterilization.

Critics of large-scale additive manufacturing using filament-based technologies often cite surface finish as a barrier to widescale adoption. The industry is approaching this from multiple angles, including a serious effort to drive the part design community to rethink how they define a “good” surface. The Class A finish popularized by the automotive and consumer goods industry is changing. Matte and semigloss finishes are appearing on expensive production automobiles, and in consumer goods the popularity of over molded soft touch TPU’s and TPE’s has driven a shift in consumer thinking about surface finish.

While Mattia embraces the look of FFF parts, surface finish and processes are available for applications that need it. BigRep recommends several technologies including sanding, plating and painting to achieve a good finish.

These days, there is also another imperative: Sustainability. In many markets, recyclability is a regulatory imperative, and in others it’s a selling proposition. In every case, it’s a factor that part designers consider when choosing a material. With FFF 3D printing, the materials are well-characterized commodity and engineering thermoplastics, most of which are recyclable using conventional technologies. This is an increasingly important factor even in industrial applications, as Europe has led a global push toward product lifecycle management that requires manufacturers to end-life their own products with little or no waste.

“We have a biodegradable ABS-like material, called PRO HT. The nice thing about it is that it doesn't harm the environment and can even offer better characteristics than commodity ABS does. I heard something months ago, which still sticks with me: every 3D printed part that was ever made still exists, and that's scary. Because I've been around the industry for more than a decade, and I think about how many parts were printed by all the manufacturers and all the customers. And they're either in use or in some landfill somewhere.”

Disposable or not, volume is key. For millions of parts, injection molding is difficult to beat. For one part, cutting and forming is king, although additive is changing this equation. For moderate volumes, however, additive manufacturing—and particularly FFF—is the best cost-optimized solution for fast, consistent parts in volumes from one to a hundred. The major limiting factor has been part size, which BigRep addresses with a very large one-cubic-metre working envelope.

Is there a single factor to help companies implement large-format additive manufacturing? For Marangell, he notes that the process starts with motivated people. “You'll always need an expert. You need a champion to be passionate about the change of technology inside their company. From there, the possibilities are endless.”

For more information on BigRep America and large-format additive manufacturing, click here.