Can pad printing help overcome medical device marking challenges?

Eric Purviance, sales manager, TouchMark a Delphon Company, outlines the challenges that pad printing can overcome when marking medical devices. 

Printing on medical devices is more challenging than ever. Pad printing is an ideal choice for medical device marking because it enables printing high-quality images within the precise tolerances required by the medical device industry. This article covers the benefits of using pad printing methods to overcome medical device marking challenges.

Why is device marketing important?

Devices related to medical and healthcare, such as catheters, syringes, handles, housings, shafts, tubes and connectors, come in all shapes and sizes and are manufactured from a variety of medical-grade plastics. Precise, permanent marking of these devices with unique identification, units of measure and/or device placement lines is vital to protecting patient health. However, this critical step faces some challenges:

• Plastics used to manufacture the devices often have low surface energy, making permanent ink adhesion difficult.
• Both the devices and the polymers from which they’re made have grown more complex.
• Medical devices are often irregularly shaped, with intricate topographies. 

The solution: Pad printing. In this technique, an image is transferred from a silicone pad onto a 3D object. This technology, together with highly specialized fixtures and process control, allows for more precise markings than inkjet or other types of printing. Capable of transferring prints onto substrates with photographic accuracy and line definition down to 0.0003 in. pad printing has become part of the overall medical device manufacturing process.

Pad printing considerations

Inks and ink adhesion. Medical-grade plastics can be lubricious, with low surface energy, and may contain additives that prevent ink from adhering. Pad printing contract manufacturers specialising in medical devices have long worked to develop ink-selection methods and pre- and post-print processes that ensure a permanent ink-to-substrate bond. For example, effective pre-treatment raises the surface energy of medical-grade polymers (e.g., PEEK, polyimide, nylon, acrylic, polycarbonate, polystyrene), modifying surface tension and promoting ink adhesion without affecting substrate integrity.

Inks used with medical devices are subject to strict guidelines: they should meet Class VI requirements and be resistant to harsh sterilisation processes. Additionally, medical-grade inks used on catheters, tubing, syringes, and other medical components must comply with FDA standards for products coming in physical contact with the human body. To ensure permanent adhesion, the ink must be optimally cured.

Difficult-to-print devices. Medical devices take on all shapes and sizes. For example, narrow width microcatheters are used to insert devices for minimally invasive procedures as they can navigate complex vasculature within the human body. They range in diameter from 0.70-1.30mm and typically require 360-degree markings. Precise placement of these markings in the right location is imperative to catheter function, requiring a highly skilled print process.

Other medical devices can be textured with irregular shapes and concave or convex surfaces. Creating the right print process to ensure high-quality markings requires a pad print provider with extensive experience, proprietary equipment, and high-quality manufacturing capabilities. The final goal is a repeatable pad printing process in which every part looks exactly as the designer intended.

Quality control, safety, and traceability. Effective quality-control systems are essential to medical device pad printing. Maintaining a documented quality assurance system for adherence to the processes and procedures outlined in ISO 9001:2015 standards ensures that customer devices consistently meet design specifications and FDA requirements. Quality systems that cover product traceability to batch level, incoming material inspection, maintained lot integrity, ink adhesion tests (standard and customer specified), and final inspection reports are hallmarks of qualified medical device pad printers.

Device safety is also paramount. Contamination is always a concern, and certain materials must not come into contact with medical devices. Pad printing is often performed in a clean environment to achieve medical device manufacturing cleanliness standards and ensure consistent quality monitoring.

Pad printing contract manufacturers are also required to provide full traceability of all inks, additives and pre/post-treatment processes used. In the event of product recalls, this information helps identify sources of contamination or other concerns.

Conclusion

Pad printing is a valuable contract manufacturing service for medical device original equipment manufacturers. To ensure success, look for an ISO-certified partner that will work directly with you to adhere to tight specifications, and has traceability and quality control systems in place to ensure proper, permanent medical device marking.

 [EP1]The pad is 3D, the image on the cliché is 2D, if that is what you meant.