Creating medical marvels with laser technology

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Keely Portway explores the use of lasers in medical device manufacturing, including how they have played their part since the start of the pandemic

Amada Weld Tech uses fibre lasers and femtosecond lasers in the manufacture of stents. (Image: Amada Weld Tech)

Lasers have been used in manufacturing across industries for decades. In more recent years, the flexibility and precision of the technology has led to them being increasingly used to make medical devices.

Many of these devices contain electronics and are generally made of different metals with different characteristics that have been welded together. Fibre lasers are often used for this task, thanks to their ability to create a strong enough weld seam so that medical device manufacturers can be assured their product will be safe for long-term use.

Laser-based additive manufacturing has also come to be more widely used in the medical sector. It can produce almost any shape, even very complex and intricate structures.

The benefit here, in terms of safety and longevity, is that it reduces the need to manufacture a product in multiple parts.

Ramping up ventilator production

The use of lasers to manufacture medical devices has accelerated even further in the past year, due in no small part to the pandemic. In the UK, for example, a consortium of UK industrial, technology and engineering businesses from across the aerospace, automotive and medical sectors, came together to produce medical ventilators for the UK’s National Health Service (NHS), under the collective name VentilatorChallengeUK.

The consortium has spent the past year working together to deliver the Penlon ESO 2 and Smiths Parapac plus ventilators to the NHS. Ventilators consist of numerous components that require either laser welding, laser marking, or a combination of both to manufacture. Such components include: power supplies; air compressors, pumps and bellows; pressure regulators; valves; electric motors and motor controllers; pressure, oxygen and flow sensors; heat and moisture exchanging filters; and air and Hepa filters. Each consists of sub-components, and are typically manufactured separately, then combined before being shipped out to medical settings. Many companies involved in the VentilatorChallengeUK stepped up production of such parts and components over and above – and in some cases, instead of – their core business.

Engineering firm Renishaw was a founding member of the consortium and has been mass-producing critical components for medical ventilators. The company has dedicated a significant part of its UK manufacturing sites in Gloucestershire and South Wales to producing precisionmachined components for the two different ventilators, with both sites running seven days a week.

Marc Saunders, director of group strategic development at Renishaw, explained: ‘Ventilators are sophisticated medical devices and we felt that our capabilities would be best applied to helping scale up the production of designs with existing technologies. We soon realised that many other industrial companies were thinking the same way and that we would need our combined capacity and capabilities to achieve this endeavour.’

Renishaw was one of a network of suppliers co-ordinated by the consortium. Other members included: Accenture, Airbus, AMRC Cymru, Arrow, DHL, Ford, GKN Aerospace, Haas F1, HVM Catapult, Inspiration Healthcare, McLaren, MercedesAMG F1, Meggitt, Microsoft, Newton, Penlon, PTC, Racing Point, Renault Sport Racing, Rolls-Royce, Siemens UK & Siemens Healthineers, Smiths Medical, STFC Harwell, STI, Thales, Unilever, Williams Advanced Engineering and Williams F1.

Many of the participants, like Renishaw, were using their capabilities to make ventilator components for the first time. However, it is not the first time for the firm when it comes to manufacturing for medical applications, being a renowned supplier of in-lab dental CAD/CAM systems, and also leveraging its expertise in metal 3D printing for the manufacture of dental frameworks. The company additionally has experience in producing neurological products such as medical devices, software and surgical robotic systems for procedures such as deep brain stimulation for Parkinson’s disease, and stereoelectroencephalography for the treatment of epilepsy.

Renishaw has demonstrated how additive manufacturing can be used in the production of spinal implants. (Image: Renishaw)

Renishaw has previously demonstrated how additive manufacturing can be used in the production of spinal implants, in collaboration with Irish Manufacturing Research (IMR) and manufacturing software company nTopology. For the project, IMR designed a representative titanium spinal implant, aimed at the cervical spine, using nTopology’s generative design software. IMR then manufactured the implants using Renishaw’s RenAM 500M metal additive manufacturing system. The technique was beneficial in producing spinal implants with lattice structures, which could otherwise prove difficult to achieve. This infrastructure is lightweight, and can be optimised to meet the required loading conditions, plus, it has a greater surface area, which can aid integration of the prosthetic device into the body.

To prepare for the work on the ventilators, the firm temporarily shut its UK manufacturing facilities to introduce additional measures to protect the welfare of its employees. ‘We reorganised our factories to increase spacing, as well as zoning areas to restrict movement around the sites,’ explained Gareth Hankins, director of group manufacturing. ‘Hygiene regimes were enhanced to minimise the potential risk of the spread of infection. Our staff responded magnificently to this challenging situation.’

The VentilatorChallengeUK project concluded in July, after more than doubling the stock available to the NHS. During that time, ventilator peak production exceeded 400 devices a day, with the shortest time taken to achieve 1,000 ventilators being three days. Despite global competition for parts combined with lockdown challenges, the consortium sourced parts from more than 22 countries, with the furthest distance travelled by a single part being 5,226 miles.

The consortium achieved full MHRA approval for the Penlon ESO 2 device in just three weeks, becoming the first newlyadapted ventilator design to be given regulatory authorisation as part of the UK Government’s fight against the virus. It went on to secure a CE mark.

‘It was an extraordinary few weeks, with so many companies from different fields aligning on a single goal and pulling together so effectively and so quickly,’ said Saunders. ‘The consortium’s key message is that “every ventilator produced is a life saved” and Renishaw is proud to be playing its part in this vital endeavour.’

Battery backups

Amada Weld Tech has also turned its welding expertise – using both lasers and other welding technologies – to aiding the fight against the pandemic. As a key supplier to both the medical and battery industries, the firm has been listed with the UK government as a supporting manufacturer for the production of ventilators and medical systems, which it helped increase the production of.

According to David Van de Wall, laser sales manager for the company, one of the biggest challenges for hospitals is electrical power failure. This is because backup generators offer the first line of defence, so, in the case of total or extended power failure, battery technology is critically important to life-sustaining care. Therefore in May, Amada Weld Tech increased its strategic partnerships with manufacturers of battery modules, used in vital life support systems such as ventilators. In addition to such systems needing a reliable battery backup in the event of a total power failure, battery power ensures essential support and monitoring can be maintained safely as patients are moved between wards.

 

Welding technology has been vital for the production of battery packs for life support systems throughout the pandemic. (Image: Amada Weld Tech)

Amada Weld Tech provided technology, including its high duty DC resistance welding power supply and parallel gap weld heads, to battery pack manufacturers rushing to increase production as the pandemic took effect.

Van de Wall said that the demand for ventilators exceeds the production capacity of typical ventilator manufacturers, and acknowledged that manufacturers who usually produce other products have found themselves switching production over to meet the increase in ventilator demand.

‘Manufacturers already using advanced welding technologies are typically well poised to switch their production over to ventilators, because there is extensive welding demand in all of the aforementioned ventilator components,’ he said.

Laser marking, laser welding, resistance welding, hot bar bonding and micro arc welding are all used in some way during the manufacture of these components.

In light of this, the company committed to providing manufacturers with additional welding technology, as well as support to existing customers looking for ways to adapt their existing technology to new applications.

‘Adaptation to facilitate rapid ventilator production is a critical component of response to the pandemic,’ remarked Van de Wall. ‘Superior welding technology, in particular, will be an important piece of this puzzle, now and moving forward.’

Superior stent manufacture

Like Renishaw, Amada Weld Tech was not new to the medical devices field, having previously worked with many medical device experts to supply laser welding, laser marking and laser cutting technologies. One area of expertise is making stents, the elastic structures made from metal or polymers that are implanted into the human body to give support to blood vessels, food pipes and other organs.

These structures are manufactured from raw materials in the form of sheets, ribbon, wire or tubing, with the latter two most widely used. Laser cutting is commonly used to remove any excess material and create the desired flexibility. Lasers can also be used to automate wire cutting for wire stents, with such wires often joined using laser welding. Amada Weld Tech supplies laser systems for all of these tasks. 

Laser cutting of stents has developed rapidly in line with demands from the medical device industry,’ said Van de Wall. ‘It is possible to laser cut extremely complex shapes in 1 to 25mm outer diameter tubes, with walls as thin as 0.2mm. Together with the trend to further reduce strut dimensions from about 110µm down to merely 60 to 85µm, these requirements demand an accurate laser cutting system.’

Amada Weld Tech works with fibre lasers and femtosecond lasers for this purpose. ‘We found these to be the most capable types of lasers for our customers’ demands,’ said Van de Wall.

‘The average power required for smallscale tube-cutting applications is, in most cases, relatively low. Most stainless steel stents are typically cut with 200 to 500W fibre lasers, with higher power levels needed only for nitinol.

Femtosecond lasers typically range between 10 to 50W average power. Power levels alone do not indicate much, however, as the cut quality, the speed of the movement system and the heat load on the stent typically dictate that the maximum power that can be used is significantly lower than the maximum power of the laser.’

A helping hand

Across the Atlantic, GE Healthcare helped lead the charge in aiding the pandemic effort. The company’s additive manufacturing division initially used its expertise to create 14,000 face masks for hospital ships and Navy personnel.

In its Madison, Wisconsin, facility the firm also leveraged 3D printing to ease supply chain bottlenecks and speed up ventilator production.

‘GE Additive has offered their capacity to help print ventilator parts,’ said Jimmie Beacham, executive chief engineer for advanced manufacturing at GE Healthcare.

‘Many of their customers have also offered up their excess capacity to us. Everyone is very willing to help us with the capacity, once we design the additive parts.’

Initially, the firm focused on the more immediate tasks, such as training new workers, strengthening supply chains and bringing in new equipment. But longer term, it aims to use technologies such as 3D printing to further speed up production.

Once again, GE is not a newcomer to medical applications, having used its technology for several different products in this area.

Most recently GE Additive collaborated with Tsunami Medical on the Giglio Interspinal Fusion System, which was designed for lumbar diseases with an indicated segmental requirement. The system focuses on developing implants that are almost ready for use, straight from a metal additive manufacturing machine. Giglio consists of an interspinal spacer device and the necessary tools for its positioning and fixing in a minimally invasive operation.

GE Additive’s direct metal laser welding technology was used to create the Giglio Interspinal Fusion System. (Image: GE Additive)

Five mobile, articulated pieces enable the extraction of fins for anchorage to the vertebrae. A surgical operation makes an incision for the passage of the device. This is correctly positioned using a guide wire stretched from the insertion point. Once the device is positioned, it is tightened by a special tool, together with the guide wire.

It is here that Tsunami was able to take advantage of GE Additive’s direct metal laser welding (DMLM) technology in a number of ways. For instance, it offers the ability to create precise geometries, including gears and mechanical moving parts, on a very small scale, with no assembly needed.

Case study: Hypotube manufacturer makes full use of laser processing

Cambus Medical, in Galway, Ireland, has become a global market leader in medical device manufacturing through targeting and achieving excellence in a very specific area: hypotubes and related components (such as catheter shafts) for manufacturers of percutaneous transluminal coronary angioplasty (PTCA) catheters.

In addition to its unique PTFE (Teflon) coating capabilities, Cambus is expert in using a broad range of manufacturing technologies, including laser cutting, laser welding and laser marking, together with traditional technologies such as electrical discharge machining (EDM), passivation and injection molding.

According to Barry Comerford, Cambus co-founder and CEO, lasers play a key role in everything the firm makes.

Why lasers?

The development and refinement of PTCA in the 1980s brought about a revolution in the treatment of coronary artery disease (CAD). The founders of Cambus had several years’ experience supplying components for this purpose, before deciding to start their own company in 2006.

‘Our PTFE coating system was certainly the catalyst for starting our business, but from the very beginning laser processing was one of the main enablers,’ Comerford explained. ‘Lasers were just appearing in PTCA work and our first customer wanted a “cutting edge laser-made” product. So we made a bold decision to spend a substantial part of our start-up cash on two Rofin (now Coherent) machines: a StarCut Tube laser cutting machine and a StarWeld (now the Select series) laser welding system.’ Both machines are still running today.

‘Not only did laser technology give us our first customer, it also gave our fledgling business a credibility for cuttingedge products, which older technologies such as EDM could not,’ Comerford continued. ‘Soon we were picking up business in areas ranging from PTCA devices to related components, such as pressure sensing guidewires. And today we also have a growing business in structural heart products, such as TAVR and TAVI.’

Cutting slots on a tubular component to enable flexible delivery

The company has always worked closely with its customers in developing custom and standard products based on delivering the highest levels of performance, in terms of torque, trackability, flexibility, lubricity, inflate and deflate times and so on. In addition to catheter shafts, Cambus Medical also produces many high-precision micro component solutions, speciality needles and wire assemblies utilising the impressive range of laser and non-laser technologies employed in the business.

Strong market growth

In addition to welding, drilling and cutting, many Cambus products require marking, for functional and/or identification purposes. Since all its products are for single-use applications, they don’t need black marking based on ultrashort pulse (USP) lasers. Instead they rely on conventional marking with a fibre laser that provides a cost-effective solution for directly marking the metal or for coating removal.

Thanks to continuous strong growth across each of the above applications, Cambus now operates seven Coherent StarCut Tube series laser cutting machines, six Coherent Select series welding machines, and five laser marking systems.

Some of the diverse microcomponents manufactured by Cambus, thanks to the flexibility and versatility of laser processing

Cambus has stayed very loyal to Coherent for three primary reasons, according to Comerford: ‘First, we benefit from having uniform equipment: the same hardware, the same software, and most importantly the same results. We handle contracts from single units up to full volume manufacturing, therefore we need consistent quality and tolerances, as well as high yields. Machine reliability is just as important; we typically operate with two four-day 40 hour shifts plus a weekend shift. And we still operate our original 2006 machines! We work these machines hard and so we really depend on the superhigh reliability and prompt quality service we get from partnering with Coherent. And lastly, these machines are very versatile and user-friendly, enabling Cambus to provide a quite diverse product offering, in terms of size and shape, as well as a huge range of batch sizes.’

The StarCut Tube machines are self-contained CNC-style automated systems featuring up to four cutting axes and a user-friendly GUI. Today these are available with a choice of a microsecond fibre laser for high throughput, or a femtosecond ultrashort pulse (USP) laser for the ultimate surface quality, or even both lasers in a hybrid machine. The use of a granite cutting platform is a key feature that ensures high precision, so users can cut struts as thin as a human hair, while processing tubes up to 30mm diameter, as well as cutting flat stock.

The Select series of welding systems are multi-axis (linear and rotary) manual welders that support semi-automated and automated operation: either joystick control or fully-CNC programmed. All parameters can easily be adjusted without any special know-how via a multifunctional joystick and large colour touchscreen.

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