Boston Centerless officials have appointed Impact Ireland Ltd. as the exclusive distributor of precision bar products to the medical device market for the Republic of Ireland and the United Kingdom.

“By adding Boston Centerless to Impact Ireland product offering, we enhance the products and services offered to our customers while helping them improve their products and reduce costs,” says Impact Ireland Ltd. Chairman and CEO Don Clarke.

“There could not be a better partner for us in Ireland and the UK,” says David Smith, vice president of business development for Boston Centerless.

Industry appointments

Mark Wright is president and CEO at Methods Machine Tools Inc., assuming all operating functions at its Sudbury, Massachusetts, headquarters and seven direct offices throughout the U.S. and the company’s national distribution network. Wright’s career spans nearly every level of operating responsibilities in a wide variety of industries including software, hardware, machinery, and services.

U.S. Secretary of Commerce Wilbur Ross has appointed Harry Moser and Thomas Dustman to the Investment Advisory Council. As part of the 25-member council, they will advise Ross on issues affecting business investment and economic development. Moser is the founder and president of the Reshoring Initiative. Dustman is Sunnen Products Co.’s director of sales – Americas. “The Investment Advisory Council will help us further develop, adapt, and expand policies to help U.S. and international firms recognize there is no better place to do business, grow, succeed, and create jobs,” Ross says. 

No matter what your industry, disruption in any part of the supply chain impacts every step that follows. For medical manufacturers, healthcare organizations, and patients, recent closures of ethylene oxide (EtO) sterilization facilities could reduce available medical devices.

Issues of safety at Sterigenics’ Willowbrook facility in Illinois first came to light in Spring 2018 after air sampling by the U.S. Environmental Protection Agency (EPA). One of the conclusions of the Agency for Toxic Substances and Disease Registry (ATSDR) noted, “If measured and modeled data represent typical EtO ambient concentrations in ambient air, an elevated cancer risk exists for residents and off-site workers.”

In February 2019, Illinois EPA Acting Director John J. Kim issued a Seal Order for the facility which handled EtO sterilization for 594 types of medical devices. By September, Sterigenics’ Cobb County, Georgia, sterilization plant – periodically idled for upgrades since August – was ordered to remain shut down until obtaining a new accurate Certificate of Occupancy.

In between these two closures, the Michigan Department of Environmental Quality (MDEQ) Air Quality Division began enforcement action when EtO emission levels at Viant Medical’s sterilization plant were higher than expected. By March, the ISO-certified medical device contract manufacturer announced it would be closing its sterilization plant by the end of 2019, stating in a letter that, “sterilization services make up a very small part of overall business model and operations.”

While it may be a small part of Viant’s operations, it’s a key part in the medical device supply chain. By October, two additional Becton Dickinson (BD) sterilization plants in Georgia were facing shutdowns but a last-minute agreement between BD and the state is allowing operations to continue as long as the company installs additional pollution control equipment.

With more than 20 billion sterilized devices sold in the U.S. – accounting for 50% of all devices requiring sterilization – reduced capacity could cause medical device shortages. This threat has kept the U.S. Food and Drug Administration (FDA) busy, working to mitigate or prevent potential shortages. Device manufacturers and healthcare providers have been asked to keep the agency updated on potential supply issues. The agency said it will fast-track sterilization site changes for Class III medical devices, changing review time from 180 days to 30 days. And, in July, two public innovation challenges were held to identify new or alternative sterilization methods (see electron beam sterilization story, pg. 12) and technologies or ways to reduce EtO emissions, details available later this year.

While the U.S. may have averted medical device shortages for now, medical device manufacturers relying solely on EtO should consider available alternatives.

Elizabeth Engler Modic, Editor
emodic@gie.net

Photos: Tangible Solutions Inc.

Many orthopedic implant companies claim their technologies facilitate bone ingrowth (or allow bone growth). Little clinical evidence backs up these claims, other than titanium’s promotion of an environment for bone to grow. Plasma-spray or acid-etched titanium surfaces without substrate porosity, for example, may yield surfaces for initial expulsion resistance (preventing the cage from moving after implantation) and provide surfaces for bone to grow onto, but they yield little long-term ingrowth to provide the best fixation and long-term results.

Industry research has established common pore and strut sizes, however, further challenges must be studied:

• Surface morphology of lattice structures – macro, micro topography
• Lattice type, shape manipulation for optimal initial attachment, long-term proliferation
• Correlation between optimal pore/strut sizes, macro stiffness of structures – preventing stress-shielding, adjacent biological issues
• Manipulation of mechanical properties via computational methods (functional lattice grading, topology optimization)

Many software tools struggle to build the kinds of structures that will lead to the next generation of orthopedic implants. Furthermore, selective laser melting (SLM) machines are becoming more advanced, manufacturing complex structures with strut sizes smaller than 0.100mm (0.004") and features as small as 0.080mm (0.003").

Next-generation software provides tools to harness SLM capabilities, allowing advanced lattice-feature manipulation. Newly developed capabilities allow design engineers to take triply periodic minimal surface (TPMS) lattices and grade them to any ramped structure.

Rather than stop at linear remapping, any geometry representation can be altered in each axis with any complex parametric equation. Complicated models can also be generated via parameters or topology optimization and used to functionally grade structures.

Using the inputs (See Figure 1), the volume lattice can be thickened with the Voronoi lattice input. The amount of thickening can be controlled precisely, given parameterization. Where the Voronoi lattice material exists, the final lattice thickness will be greater. The same principles can be applied when setting up the volume lattice – the cellular point spacing can be ramped via any representation that can be conceived and applied.

Complex lattices can also be transformed from one to another with no definable transition point, potentially limiting single weak shear points. Having the freedom to achieve the strut and pore size that produces biological benefits, and maneuvers the structural elements, allows for complex manipulation of orthotropic properties. This further helps engineers evaluate how bone ingrowth will change the macro stiffness of the construct and how to create lattice elements that provide long-term benefits for biological optimization.

Manipulating the mixed elements is not bound to a linear input. Objects can be mixed using complex structures or primitive models, (See Figure 2) where the same two TPMS lattices are mixed using an oblate spheroid. Where the sphere exists, the cells are a Gyroid TPMS structure, and the design moves from the sphere transitions to a Lidinoid cellular structure with no obvious transition point.

These tools transition complex lattice shapes to external solid features, simulating biological mimicry of bony structure (cortical and trabecular elements) and the seamless organic transition between them. This type of control over the internal and external structures, as well as discrete control of the transitioning elements, can help give implant developers the ability to alter structural properties on a macro and micro level. It also helps them understand how structures alter as bone integrates into them and engineer implants with specific ingrowth factors.

This can be further refined by setting up transition phases from one structural element to another – to define continuous mechanical properties from entirely different structural types.

nTopology https://ntopology.com

Tangible Solutions Inc. https://www.tangible.com

A father and son backyard project will soon see the creation of a life-size, functional Lamborghini Aventador. The car is not entirely 3D-printed but demonstrates the potential of additive manufacturing (AM) for the wider vehicle industry. Kostas Poulios, principal design and development engineer at Pailton Engineering, explains how he used 3D printing in large vehicle manufacturing and whether it could play a role in the production of safety critical parts.

Outside of novelty projects, 3D printing is already an important part of vehicle production. From tooling, parts manufacture, design, and prototyping components, the industry is widely considered a pioneer of integrating 3D printing into design and manufacturing support processes. However, automakers are not producing safety critical vehicle parts with AM.

Steering system

Steering systems are put through intense conditions throughout their lifespan, particularly when used in large vehicles such as military, utility, and commercial trucks. Each part of the system, including the drag link assemblies, steering and suspension ball joints, and bevel boxes must be able to withstand heavy shock loads.

Due to high shock loads, components for steering systems cannot be manufactured with some of the common materials used for 3D printing – at least, not to a useable standard. For instance, Acrylonitrile butadiene styrene (ABS), a thermoplastic filament that is regularly used for fused deposition modelling (FDM), does not provide adequate properties for the manufacture of steering system parts.

Although strong and lightweight, the material is not powerful or durable enough to be used in a steering application. Instead, ABS modelled parts are suitable only for rapid prototyping.

An alternative material would be metal matrix composites (MMCs), composites with at least two constituent materials. Hybrid composites that combine three or more materials provide more strength, as several elements can be combined to improve material properties and ensure the part meets requirements.

For niche steering systems, such as those used in commercial trucks, construction, and military vehicles, MMCs can provide designers with an opportunity to expertly engineer the metal that is used to make their part, while also reaping the advantages of 3D printing. This includes the potential to topologically optimize parts to maximize strength-to-weight ratio. This is particularly advantageous when used in combination with other design tools, such as finite element analysis (FEA).

To manufacture MMC safety critical parts requires selective laser sintering (SLS), a technology that prints components from metal powder. Currently, this method can be costly and time consuming. Looking into the future, when SLS 3D printers become widely available and more cost effective to use, this may change.

As in every optimized steering system, any work outside the conventional manufacturing processes will be more expensive. An exception to this rule would be low production volumes. However, these cases are usually undertaken with the intention of larger volume production in the future.

When considering whether to implement 3D printing into parts production, manufacturers must understand that the advantages might not outweigh the initial cost. This is certainly the current case for 3D printing for safety critical parts. However, the method is valuable in other areas of production.

AM is successfully used in the design phase of safety critical components. For example, Pailton Engineering uses an HP DesignJet to create prototype steering system components from ABS, including ball pins, drop arms, steering wheels, suspension joints, and forgings. In these cases, the 3D-printed part is not used for production but is replaced with a production equivalent once the design is finalized.

At Pailton Engineering, using AM during design provides the design and production engineers with a visual representation of steering parts and assemblies. This helps identify issues and improvements before production begins to provide customers with the correct first-time solution, every time.

Pailton Engineering Ltd. http://pailton.com