Permanent marking of plastic medical devices represents one of the most complex challenges in the field of industrial traceability. The industry demands absolute accuracy where code legibility must be combined with stringent requirements for biocompatibility and resistance to sterilization processes, without compromising the structural integrity of the device.
UV technology: an innovative approach to marking
“UV radiation has revolutionized the approach to marking medical devices,” explains Mario Palmieri, global head of LASIT Laboratories. “Unlike conventional infrared lasers operating at 1064nm, UV radiation interacts with the plastic material in a fundamentally different way. The higher photon energy of the UV beam allows a photo-physical interaction with the material, significantly limiting the thermal effect that characterizes IR lasers instead.”
Materials and applications in the medical industry
The medical industry uses a wide range of plastics, each with specific applications and marking requirements:
PMMA (polymethyl methacrylate):
- Applications: intraocular lenses, diagnostic devices
- Marking characteristics: requires medium to high powers for optimal contrast
PC (polycarbonate):
- Applications: device housings, transparent components, medical connectors
- Marking characteristics: excellent response to UV radiation
PEEK:
- Applications: surgical implants, sterilizable components
- Marking characteristics: needs specific parameters to preserve biocompatibility
Silicone elastomers (LSR/HCR):
- Applications: tubes, respiratory masks, gaskets, infusion sets
- Marking characteristics: requires extreme precision to maintain structural integrity
PA (polyamide):
- Applications: catheters, medical tubing, plastic surgical instrumentation
- Marking characteristics: focus on resistance to sterilization cycles
ABS medical grade:
- Applications: housing of electromedical devices, disposable components
- Marking features: precise power control to avoid charring
Resistance and validation
Durability of marking is a critical issue. Medical devices must maintain readability of the Unique Device Identification (UDI) code after:
- Repeated sterilization cycles (autoclave, gamma ray, ethylene oxide)
- Exposure to hospital detergents and disinfectants
- Accelerated aging test
- Medical-specific chemical resistance testing
Process control and integrated vision
Quality assurance of marking is based on an integrated vision system that verifies in real time:
- Precise positioning on curved surfaces or complex geometries
- Quality of marking according to AIM-DPM standards
- Readability and contrast
- Absence of thermal damage to the material