A patient-specific cranial flap can be taken from a patient's CT or MRI scan and converted to a CAD file. Oxford Performance Materials then creates a representative shape to fill the area of the bone defect and optimize that shape for load or biofunction, such as to promote natural bone-in growth.
Photo courtesy of Oxford Performance Materials.

SOUTH WINDSOR, Conn.--Oxford Performance Materials (OPM) is building upon its basis as a company that originally produced proprietary, biocompatible high-performance thermoplastics, known as PEKK polymers, and is transforming into one that is on the leading edge of manufacturing technology. Today, the company uses additive manufacturing to produce both biomedical parts that mimic human bone, as well as low-weight, high-performance industrial parts mostly for the aerospace and semi-conductor industries.

Having recently launched two products, OsteoFab^TM implants for the biomedical industry and OXFAB^TM parts for industrial applications, OPM (www.oxfordpm.com) is touting its new approach to manufacturing, dubbed "Design to Constraint," which bucks the traditional way structures are designed. "We're moving to a paradigm where manufacturing limitations are pretty much nonexistent," said company president Scott DeFelice in a phone interview. Instead of being limited by tooling or molding, in which the design engineer is a slave to a prescribed manufacturing method, Design to Constraint offers a paradigm shift where all of a sudden "elegant algorithms" are used to design structure. "When you move to a free-form additive fabrication method, the designer becomes the dominant player and the manufacturing method becomes the slave," DeFelice said.

The small, 17-person company is basically doing structural design "backwards" by incorporating a three-pronged technique that results in the most efficient production of organic structures that can be printed, most notably on the company's new EOSINT P 800 SLS machine. Purchased with funds awarded by Connecticut Innovations, Inc.'s BioScience Facilities Fund, the machine is housed in the company's new 16,000 sq. ft. facility.

"Now we've combined really unique software with our structural material and our additive process to build structures that are designed from an algorithm in a very efficient way," DeFelice said. "It's a combination of all these things that will ultimately turn design on its head. It's a very powerful, real paradigm shift."

A recent example was a cranial flap implant produced using OPM's OsteoFab^TM process, where the OXPEKK-IG® (implant grade) polymer was used to print an implant derived from a CT scan or MRI file for perfect anatomical fit. The OXPEKK® polymers have properties comparable to human bone, and this cranial flap needed to enable bone to grow into the edges. Through the company's "Coherent Implantology Process," fit, form and bio-function are digitally calculated, constructed, and then produced via the SLS process.

OXPEKK-IG polymer for implants has been tested according to ISO 10993. OXPEKK-MG® (medical grade) and -IG products have had thousands of successful implantations, and have been used in devices cleared for medical and implantable use by the FDA, KFDA, ANVISA, COFEPRIS, ANMAT, DIGEMID, and a number of CE-Marked devices.

"What we're talking about is a combination of the material, which is biocompatible and structural; the manufacturing method, which is unlimited; and the software, which designs to constraint," DeFelice explained. "It's those three components which are basically the coherent method of design." In the biomedical world, it's called "coherent implantology," where anatomical function and biomechanical strength combine to meet specific morphological needs that will allow vascular or bone growth.

The company initially started selling its OXPEKK® biomedical polymers as bars or pellets about seven years ago. These polymers are reported to offer radiolucency, density and stiffness similar to that of bone, and abrasion resistance.

Compared to metals, polyketones are much more pure, DeFelice said, with no ions or particles coming off that would compromise people's bodies. "Metal is coming under a lot of pressure for a lot of reasons, and the science is getting very strong so that we're seeing the adoption of more pure materials into the market," he said, adding that OPM's polymers have an FDA Master File. "The polymers are definitely at a point to change a lot of things and PEKK is certainly, I would say, leading that evolutionary change."

Because OPM is combining material science with process science, DeFelice likens his company to Apple rather than Microsoft in that it is a "collector of interesting technologies and we are able to combine those things and innovate around them to bring technologies together that create new solutions." Pushing these technologies forward has led to what DeFelice calls "ground-breaking innovations," and the enhanced SLS capability positions OPM to lead innovation in biomedical technologies. The company recently exhibited at the American Academy of Orthopedic Surgeons (AAOS) meeting in San Francisco, where they highlighted their polymers and introduced the OsteoFab^TM process. "For us, it was the first time out of the box with this technology after six years in development," DeFelice said. "We had some surgeons come up to us who were blown away."

The release was most profound for those in the medical industry who were able to recognize that the implants exhibited were free-form fabricated, additive, structural, and created by an algorithm.  "People who understand structure and design, and understand a particular industry, whether it's medical or aerospace, are stunned," DeFelice said, adding that the company can achieve 50 to 75 percent weight savings on aerospace parts.

The OXFAB^TM technology for industrial parts offers highly chemical resistant, heat resistant, and lightweight products that combine advanced polymers with additive fabrication techniques. A design allowables database and OPM's proprietary design algorithm are used, enabling function to determine structural form to maximize strength, flexibility, and weight as required. The design is then printed via SLS manufacturing directly from the digital file.

"Innovation to us means that we're going to improve human sustainability and we're going to deploy a lot of interesting strategies to get there, whether that means we're going to make aircraft lighter or make implants last longer," DeFelice said. "I mean there are already people running around now with OsteoFab^TM implants who would not have had such elegant solutions before."

DeFelice added that OPM is currently in some "important discussions with strategic players" in the medical industry to take advantage of this new OsteoFab^TM technology. He is also working to form a non-profit group called Foundation for Orthopedic Reconstruction (FOR) to work in conjunction with some large orthopedic companies to offer implants and surgery to people who have had traumas, such as accidents, disease, or domestic abuse. It is part of a "social mission" that DeFelice said encompasses his company's vision to improve the human condition.

"We evolved from a company that was selling plastic scrap to China for twenty cents a pound, to a company that moved into engineered polymers, into a company that moved into high-performance materials, into a company that continues to seek out the technologies that create more value," he said. "And as the basis of everything, we're going to be addressing those questions of human sustainability."