The increase in spending demonstrates how the competitive landscape in additive manufacturing continues to intensify and customer demand continues to grow. Zehavit Reisin, Vice President of Rapid Prototyping at Stratasys, explains how material developments are proving key to overcoming specific industry challenges and supporting the growth of additive manufacturing.

In addition to innovative hardware, advanced software and strong strategic partnerships, the area of material development is crucial for additive manufacturing. In the past, manufacturers focused on rapid prototyping, the initial core business of this technology. The requirements were simple, often requiring only fit checks and testing. In recent years, as the demands for realism, fit, functionality and color have increased, so has the potential for applications. Users are now using the technology to create complex and robust production tools, as well as manufacturing aids for the production area and even robust end products. In many ways, additive manufacturing materials are the prerequisite for providing designers, engineers and manufacturers with specific solutions to their challenges.

Each prototype goes through a very specific life cycle: concept review, design validation and functional testing. Rapid iterations at low cost are required in the concept review. A grade of "sufficient" is sufficient for the quality requirements here. Design validation, on the other hand, requires components with high dimensional stability that neither bend nor deform, as well as smooth surfaces. In many cases, the final appearance of the component is tested at this stage, so color, transparency and opacity are also important. In functional testing, component performance is critical and requires materials with improved mechanical, thermal and, in some cases, chemical properties. Here, it must be ensured that the materials can withstand the environmental conditions in which the end product will be used.

But of course, every application faces unique challenges, not to mention the huge differences in industry-specific and legal requirements that need to be taken into account when developing materials.

Healthcare

The healthcare sector is expected to spend $1.3 billion on 3D printing in 2018^.3 Today, many hospitals are using 3D printing to improve patient care and surgical treatment. Hospitals such as the Queen Elizabeth in Birmingham, England and the University Hospital Basel in Switzerland have achieved significant time and cost savings in the production of 3D printed medical models using PolyJet technology. The Queen Elizabeth was able to save an astonishing £20,000 per procedure and reinvest this in other areas of the hospital. In addition, the University Hospital of Basel is reducing the average operation time by more than a third: in both hospitals, 3D printing is playing a crucial role in improving patient care.

Today, patient-specific models are 3D printed and allow the surgeon to visualize the anatomy and practice the procedure on the patient-specific model. Using advanced full-color mulit-material 3D printers, models can be colored to identify critical structures. By combining different materials, functionality can be enhanced. This allows doctors to effectively practice, plan and prepare for complex and vital surgeries. However, one of the biggest challenges in healthcare is the development of anatomically very realistic models that closely resemble human tissue. This poses several challenges, from the geometry of the printed model to the need to use multiple, very different materials in a single printing process. Take our skin, for example: it is incredibly soft, yet robust - and any 3D printed model must be able to replicate this. Every day, industry pioneers are working to find this balance and produce such materials. One of the most notable solutions to these challenges is BIOMIMICS™ from Stratasys. Launched in late 2017, the 3D printing solution now enables the realization of high-precision, anatomically correct vascular, cardiac and bone structures that meet a wide range of clinical requirements. BIOMIMICS is mainly used by medical technicians as well as training and educational institutes to create realistic models that provide a more accurate assessment of anatomy than cadavers or animals.

In turn, some medical professionals require materials that are lightweight, durable or biocompatible and suitable for long-term contact with the human body. There are many other challenges associated with this, such as sterilization and certification. Manufacturers of medical devices, for example, require materials that can be sterilized using technologies that are already widely available and easily accessible. Typically, our customers use some form of high-temperature autoclave, so we ensure that our materials can withstand these temperatures. This is what drives our industry forward every day. Customers around the world are already using our materials in combination with world-class hardware and industry-recognized software to produce efficient, cost-effective and accurate tools for clinical testing and applications.

Aerospace

High temperatures and strict approval regulations are not only found in the healthcare sector. They also play a major role in the aerospace and railroad industries. These industries are naturally subject to strict regulations. The components often have to withstand the toughest conditions and increase efficiency and performance at lower costs. The most important question is always whether the material meets the stringent FST (flame, smoke and toxicity), heat release and chemical sensitivity requirements. As a result, complex and specific material properties are required to ensure passenger safety.

In recent years, media attention has focused on aerospace manufacturers who are using additive manufacturing to replace heavy metal parts with durable, significantly lighter alternatives made from 3D-printed thermoplastics. Working closely with its customers, Stratasys has developed a configuration and process methodology that enables outstanding reproducibility. One of the results of this collaboration is the high reproducibility of the Ultem 9085 material, which has a high strength-to-weight ratio and is also FST compliant. Hardware solutions in combination with Ultem 9085 developed for specific industry problems, such as our Aircraft Interiors Solution, now enable aerospace companies to certify multiple components for use in aircraft much faster.

Automotive engineering

With demands for improved fuel efficiency, constant environmental and political pressure, the automotive market is also facing constant challenges. These are quite different from those in the aerospace industry - while aircraft components are subject to strict flammability requirements, automotive components must be crash-proof - proof that components must meet the requirements of the respective operating environment.

Material development is one of the ongoing tasks at Stratasys. Among other things, engineers are working on higher chemical resistance for fuel contact and an optimal combination of strength, ductility and toughness for longer life. New materials, such as our recently introduced carbon fiber-reinforced nylon 12, are enabling new applications in the automotive industry. 3D printed composites offer the strength of metal and the light weight of plastic. Additive manufacturing not only offers the ability to produce lightweight components, but also to optimize the power-to-weight ratio through complex geometric designs using advanced software and hardware capabilities. This would not be possible with other methods.

These benefits are underlined by users across the automotive industry, including Formula 1 racing team McLaren, which operates in the demanding and high-performance world of motorsport. Using Stratasys' FDM additive manufacturing technology, McLaren produced a new race car wing in less than two weeks during the last Grand Prix season, using a 3D printed ULTEM 1010 mold tool and saving significant time compared to traditional methods.

Similarly, Volvo Trucks in France is using its FDM solutions to develop durable yet weight-optimized clamps, mounting fixtures, brackets and tool holders for its production facility in Lyon. Volvo Trucks estimates the cost of 3D printing customized ABS thermoplastic parts for direct use in the factory in small quantities at just €1/cm³, compared to €100/cm³ to produce the same part in metal. Crucially, Volvo Trucks has reduced the time to design and manufacture certain traditionally metal assembly line tools by more than 94% - from 36 days to just two days by using Stratasys' FDM additive manufacturing technology.

In view of the automotive and aerospace industries, we have identified one of the main challenges facing the transition to additive manufacturing today. The application focus is shifting more and more from rapid prototyping to tooling to finished production parts. As this trend continues, we need traceability to ensure a secure and reliable supply chain. We have already ensured this with the aforementioned ULTEM 9085 material and continue to work closely with our key customers to meet their demanding current and future requirements.

What happens next?

The requirements of these industries are not only determined by material development. Our customers also value our innovations in hardware and software as well as our expertise, training and industry-specific solutions. Every development is a leap forward for additive manufacturing. The more accurately a material replicates the mechanical, thermal and chemical properties of the end product, the more likely it is to meet the requirements of the end product. The design process becomes more efficient. In production, material properties are crucial for functionality, consistency, surface smoothness and traceability. For this area, material development is a top priority and a constant challenge. We are constantly recording the requirements of our customers and promoting innovations in our laboratories. This allows us to stay close to the needs of the market and therefore the greatest requirements.

With several industries set to spend millions on 3D printing this year, the need for customized and advanced materials will continue to grow. As the industry continues to innovate and meet these demands, additive manufacturing will find its way into more and more companies.

Zehavit Reisin, Vice President of Rapid Prototyping at Stratasys / am

^{1https://www.statista.com/statistics/590113/worldwide-market-for-3d-printing/}

^2IDCWorldwide Semi-annual 3D Printing Spending Guide

^{3https://www.statista.com/statistics/590113/worldwide-market-for-3d-printing/}