by Cassandra Balentine
The three-dimensional (3D) print—particularly additive manufacturing (AM)—world relies on a variety of materials for product and part building. Elastomers are rubber-like polymers with elastic features, which are ideal for seals, adhesives, and flexible parts.
3D printing processes that print elastomers include stereolithography (SLA), fused deposition modeling (FDM), multi-jet fusion (MJF), and selective laser sintering (SLS). Each technology has some pros and cons, but Sam Houston, senior manager, Advanced Laser Materials (ALM) global, EOS, says it really depends on the end part and what is needed to choose the right one for the application.
According to Grand View Research, the global elastomers market size was valued at USD $82.41 billion in 2019 and is anticipated to grow at a compound annual growth rate (CAGR) of 4.8 percent from 2020 to 2025.
The firm’s Elastomers Market Size, Share & Trends Analysis Report By Application (Consumer Goods, Medical, Automotive, Industrial), By Type (Thermoplastics, Thermosets), By Region, And Segment Forecasts, 2020 – 2025 report explains that elastomers are elastic polymers that are lightly cross-linked and amorphous along with glass transition temperature. They are classified as thermoplastic, diene, and non-diene. Thermoplastic elastomers (TPEs) block copolymers contain rigid and soft repeat units. Elastomeric parts are produced through three major production techniques—injection molding, compression molding, and transfer molding.
“Rising demand from key application areas coupled with advancements in the processing technologies is likely to propel the market growth during the forecast period. Elastomers are witnessing high demand from the automotive industry on account of the rising need for high-performance and lightweight materials in vehicle production. Key properties, such as high durability, strength, and pliability, allow it an ideal material for a variety of applications in the automotive sector,” says the Grand View Research report.
Several features are in demand when it comes to elastomers, including elongation at break, impact resistance, recyclability, consistency in processability, and post processing, according to Houston.
The most in demand functions of elastomers come down to the application. For example, those that utilize 3D printed, flexible elastomers often require many properties that aren’t traditionally associated with traditional 3D printed materials. Footwear applications demand high levels of durability and fatigue strength, fine features that won’t tear or rip when in use, cleanability, and a surface finish thats aesthetic has to be appealing, shares Jason Rolland, SVP of materials, Carbon, Inc.
“TPEs are used for many different things but most of the time, clients are looking for a certain shore hardness, a method used to characterize how resistant materials are to localized deformation or indentation—more or less, how hard, or soft the material is,” says Houston.
Pareekshith Allu, materials manager, Formlabs, sees a need for materials that are able to print tear resistant and durable to produce intricate surface finishes that are skin-safe in low production times.
Additionally, the ability to mimic injection molded silicones and urethane rubbers with the right durometer are highly in demand. “Effective elastomers should be able to make parts that would be difficult to cast or die cut otherwise, and chemically inert parts with high temperature stability and rebound resilience. This enables users to make seals or gaskets on demand and in the right form and fit for product development or manufacturing,” says Allu.
Demand for the feature sets required of elastomers also come down to the application and end use of a part. However, it often needs to be able to withstand certain conditions such as resistance to fatigue, tears, water, UV, impact, and certain chemicals, as well as be cost competitive to the traditionally manufactured parts, says Houston.
“Demand for these features will always be driven by the end customer and the ultimate performance of the product. Saddles are a good example of having a material that gives designers and engineers new found capabilities in the design process to meet and exceed the demands of their performance-driven users. These capabilities include, but are not limited to, variable density in a single monolithic print, breathable/light weight structures, and new aesthetics and designs that delight the customer,” adds Rolland.
Allu points out the example of casting silicone parts, which is a multi-step and laborious process. “Users usually 3D print two mold halves and inject silicone into the molds to make silicone parts. There is a challenge with designing the molds and it can be an iterative process to get the final parts. This is a slow method compared to 3D printing for quick iterations and prototyping.”
Allu also shares that transfer molding for silicone requires making molds that are then used to inject silicone to make silicone parts. “Outsourcing to service bureaus can take several days to weeks for parts and is very expensive compared to in-house 3D printing.”
Elastomers in Industry
Several industries rely on elastomers as part of their 3D production processes.
Many consumer industries benefit from the unique properties and design affordances of 3D printed elastomers. “Really anywhere that the user needs next-level performance in the areas of comfort, breathability, protection, and novel aesthetics. One area where we’re excited to see growth is in the custom products world. We want to create the systems and workflows that enable mass customization at scale for any purpose. From bespoke fit for helmets across sports, to insoles, to wheelchair seating,” says Rolland.
Houston feels the largest industries utilizing elastomers include lifestyle, automotive, aerospace, and industrial. “We have seen a rise in footwear. The use of TPEs in AM can provide unique lattice structures for a futuristic look as well as great rebound performance needed for the lifetime of the shoe. Many other verticals might use these materials to produce parts such as grippers, gaskets, seals, and latticed cushions.”
Allu also sees increased adoption of elastomers in 3D printing in healthcare, consumer goods, manufacturing, and engineering industries. “This is due to elastomers’ ability to bridge the gap between manufacturing stages, produce fully functional prototypes, manufacturing aids, and end use parts, as well as take full control of their supply chain.”
Within the aforementioned industries, specific applications utilize elastomers. Allu points out that these applications include handles, grips, overmolds, seals, gaskets, masks, damping, shock absorption, rippers, padding, and cushions.
Biomed applications include cartilage, tendon, and ligament anatomy.
In the healthcare and dental industries, labs and clinics look for elastomeric materials that produce patient-specific parts and products, adds Allu.
Rolland says soft robotics is a developing field of technology utilizing Carbon’s elastomers to create soft grippers that can be embedded with electronics, creating a sense of touch. “We have customers using our products on assembly lines to create grips that grab various shaped products for sorting. Our damping materials, like EPU 45, are often used to stabilize sensitive electronics against noisy vibrations.”
Elastomers in Use
We continue to watch the development of elastomers utilized in AM. These are increasingly popular in a range of industries, from consumer to healthcare.
Feb2024, Industrial Print Magazine