A laser focus on safety and traceability

Surgical instrument manufacturing is one area where the benefits of laser marking, and laser welding have, over the last two decades, become common place. However, the extensive use of new materials and different stainless steel grades, with the added requirement for performance and corrosion resistance, create challenges. Many manufacturers (even large international companies) make mistakes that can be avoided. 

The manufacturing of surgical instruments and medical devices demands a unique combination of precision, cleanliness, and reliability. Marking needs to be permanent, high contrast and without a crevice being formed by the laser marking process. Laser welding needs to be neat, with minimal surface distortion, and no discolouration. Usually with a very discrete, consistent weld seam.

Laser marking, welding and machining have revolutionised the surgical instrument industry. These techniques enable manufacturers to create durable, traceable, and biocompatible products essential for patient safety and regulatory compliance. This article explores the pivotal role of laser marking and welding in the modern production of surgical instruments and medical devices and looks at some of the steps companies are taking.

Laser marking in medical manufacturing

Laser marking is a process in which a focused, high-intensity laser beam interacts with the surface of a material, creating a permanent mark without physical contact. Medical-grade materials — such as stainless steel, titanium, and various polymers are commonly marked using laser processes, but what has been learnt in the last two decades? What mistakes have been made and how can these be avoided?

Types of laser marking techniques

• High frequency marking (often also called annealing): This non-abrasive process alters the colour of the material, usually to create a jet-black surface mark, mainly used for stainless steels. The result is a smooth mark ideal for surgical tools.
• Engraving: A more aggressive laser marking technique, laser engraving ablates or vaporises a small portion of the material, creating a recess or groove. This method is generally considered not acceptable for surgical instruments as it creates a crevice where dirt or debris can collect.
• Carbonisation and foaming: Frequently used for polymers, these processes change the surface chemistry to create legible marks, machine readable codes, or graphics.

It should be added that research into the safe laser marking advocates the use of shorter pulse width / high peak power lasers, to avoid higher heat input that can damage the passive layer and surface chemistry of stainless steels. There has also been good research into the surface composition using new advanced surface testing techniques, to help understand exactly what happens to stainless steels when they are laser marked – in particular, to the changes that occur to the localised chromium content, and the resistant strength of the passive layer.

Commonly used fibre lasers typically have pulses around ten times longer than most DPSS (Diode Pumped Solid State) lasers, without the advantages of the high peak powers, so problems have occurred using the fibre laser technologies that are more commonly available now. So, newer laser technologies are not necessarily better for every application. 

Stephen Henry, a Director at Sciamed, an international supplier of laser instrument marking systems states that, “We have heard first hand from a number of companies of problems that they’ve had through using the wrong laser technologies. So, not only do we sell the systems built around proven safe laser technologies, but we advise and train users in the correct use of laser settings and their effects – which is very important to mark instruments safely’.”

The benefits of laser marking include:

• Permanency: Laser marks are highly durable, resistant to wear, sterilisation processes, and harsh chemicals.
• Precision: Lasers can create extremely fine, detailed marks, including Data Matrix codes for instrument traceability.
• Biocompatibility: Unlike some other marking, printing or labelling processes, lasermarking does not add foreign substances or adhesives, ensuring that the instrument remains safe for surgical use. 
• Cleanliness: Laser marking is a non-contact and non-contaminating process, which is vital in environments requiring the utmost hygiene.
• Traceability and compliance: Regulatory bodies such as the FDA and EU MDR require Unique Device Identification (UDI) for medical devices. Laser marking provides a reliable way to apply these identifiers in a readable and enduring way.

Research we performed has identified an energy threshold where laser marking changes from a mark that can be easily removed by basic abrasion, to a permanent mark that withstands basic abrasion, and most commonly used chemical processes, passivation treatments and sterilisation. 

There are laser marking additives that can be applied to parts and materials before laser marking. However, detailed information of their exact composition is unclear, and these can create marks that alter the surface composition and the morphology of the instrument, which leads to concerns over their suitability. 

Applications of laser marking

The scope of laser marking in medical manufacturing is broad:

• Instrument identification: Serial numbers, batch codes, and manufacturer information are permanently marked for traceability and quality assurance.
• Branding: Logos and trademarks are applied to ensure authenticity and deter counterfeiting. The addition of correctly marked high contrast logo type inscription often gives a positive brand appeal to a well manufactured instrument.
• Calibration marks: Graduations and scales on instruments are laser-marked for precision and durability.
• Barcodes and data matrix codes: These enable automatic data capture, inventory management, and compliance with global regulatory requirements for Unique Device Identification.

Laser welding in medical manufacturing

Laser welding uses the intense energy of a focused laser beam to join two or more pieces of material, typically metals or thermoplastics. The process is highly controlled, enabling the formation of strong, hermetic, and contamination-free joints. Types of laser welding techniques include:

• Conduction welding: The laser heats the material just enough to cause localised melting at the interface, fusing the components together. This is ideal for thin walled or delicate parts.
• Keyhole welding: Higher power densities create a “keyhole” effect, allowing for deeper penetration and stronger joints, often used in devices that require robust sealing.
• Spot and seam welding: Spot welding is used for discrete points, while seam welding creates continuous bonds along a joint. Both are essential in assembling small components and housings. Both pulsed and continuous wave (CW) laser welding systems are available, with the former giving spot sizes and weld seams as small as 0.2mm wide. Often used with a shield gas (such as Argon), the resultant welds are bright in appearance and require little or no reworking, after welding, to remove discolouration.

Laser welding systems are now quite compact and easy to use, and some can run from single phase electrical supplies too, as the efficiency of these systems improve. The most popular laser welding systems have integrated powered movement axis controls allowing parts to be safely and easily manipulated during laser welding. 

High quality consistent results are easily achieved, and the use of filler wires are not always required. As most surgical instrument and medical device welding applications involve smaller parts and thinner weld seams the power requirements tend to be lower, which often keeps the system cost low too. 

The benefits of laser welding include:

• Precision and control: The focused energy of lasers allows for extremely precise welds with minimal thermal distortion, essential for small or sensitive components.
• Cleanliness: Laser welding is a non-contact process, reducing the risk of introducing contaminants or particulates.
• Hermetic seals: The process can create airtight and watertight seals, crucial for implantable devices and fluid-handling systems.
• Material compatibility: Lasers can weld dissimilar materials and thin or complex geometries that are difficult to join with traditional welding methods.
• Reduced need for post-processing: High-quality welds often require little or no finishing, speeding up production and ensuring consistency.

Applications of laser welding

Laser welding is indispensable in manufacturing medical and surgical products such as:

• Surgical instruments: Scissors, forceps, clamps, and needle holders often feature laser-welded joints to ensure longevity and structural integrity.
• Implantable devices: Pacemaker housings, cochlear implants, and neurostimulators rely on hermetically sealed cases to protect delicate electronics from bodily fluids.
• Catheters and endoscopes: Laser welding joins thin-walled tubing and precisely assembles miniature optics or sensors into device tips.
• Microsurgical Tools: The fine control of laser welding supports the assembly of intricate, high-precision devices used in ophthalmic or neurosurgery.

In the production of cardiac pacemakers, laser welding is used to close titanium housings after sensitive electronics are installed. The resulting welds are hermetic and biocompatible, ensuring that the device can function reliably for many years within the body. Secure leak free joints can be created without introducing adhesives or other additional materials to a part, that might compromise biocompatibility.

Challenges and considerations

While laser marking and welding offer many benefits, there are important considerations:

• Material selection: Not all materials respond equally to laser processes. Some plastics and coatings may degrade or emit hazardous fumes under laser exposure.
• Process validation: Medical manufacturing is subject to stringent validation and documentation. Laser systems must be precisely controlled and monitored to ensure repeatability and compliance with regulatory standards.
• Cost: The initial investment in laser systems can be significant, although often offset by increased throughput and reduced maintenance.
• Training: Operators need training to use laser equipment safely and effectively in the production environment.

Regulatory and quality assurance aspect Regulatory agencies such as the US Food and Drug Administration (FDA), the European Medicines Agency (EMA), and others require strict traceability and quality control for medical devices. Laser marking supports Unique Device Identification (UDI), while laser welding provides documentation of critical process parameters important for audit and validation purposes.

Both laser marking and welding processes should be subject to rigorous testing, when used in medical device and surgical instrument manufacturing. Laser marks must remain legible and durable after repeated sterilisation and use, while laser welds are often inspected using microscopy, leak testing, and mechanical stress tests etc.

Future directions

As medical devices become smaller, more complex, and dependent on advanced materials, the role of laser processing will continue to grow. Emerging trends include:

• Integration with automation: Robotics and automated inspection systems are increasingly paired with laser workstations to enhance throughput and consistency.
• Smart marking and traceability: Advanced marking strategies, such as micro-engraving and invisible identifiers, offer new ways to ensure authenticity and track devices throughout their service life.
• Ultrafast lasers: The use of novel laser sources enables processing of new materials with even greater precision and minimal thermal impact, while more expensive indications are that ultrafast laser technologies will become more popular.

Conclusion

Laser marking and welding have become essential tools in the manufacture of surgical instruments and medical devices. Their unmatched precision, cleanliness, and ability to meet demanding regulatory requirements have elevated the safety, traceability, and overall quality of modern medical products. As the healthcare industry advances, the continued evolution of laser technologies will further enhance the possibilities for innovation and patient care.