ISO 13485 and the Paperwork Behind a Qualified Marking Process

ISO 13485 and the Paperwork Behind a Qualified Marking Process

Key Takeaways

• Marking is usually a special process, because you cannot verify a mark’s durability by inspecting it — which mandates validation.
• UDI requirements make the mark a regulatory deliverable, not a convenience.
• Supplier controls extend to resin and additive, since an undisclosed formulation change alters the process.
• Change control is where systems fail, and supplier-initiated changes are the ones most often missed.

A marking process inside a medical device quality system carries obligations that the same process on a general production floor does not. Most of them follow from a single classification decision, and understanding that decision makes the rest of the documentation set coherent rather than arbitrary.

Why It Is a Special Process

Quality systems distinguish processes whose output can be fully verified by subsequent inspection from those whose output cannot. Marking falls into the second category, and the reason is durability.

Inspecting a finished device confirms that a mark is present, correctly formed and currently readable. It cannot confirm that the mark will still be readable after two years of use, after fifty autoclave cycles, after repeated cleaning with hospital disinfectants, or after gamma sterilisation. That property is determined by the process that created the mark, and the only way to establish it is to validate the process rather than inspect the product.

Everything else follows: validation is mandatory rather than optional, the process must be controlled and monitored, personnel must be qualified, and changes must be assessed against the validated state.

UDI Raises the Stakes

Unique device identification requirements make the mark a regulatory deliverable. The identifier must be present in specified form, readable by the intended means, and durable for the device’s intended life. For reusable devices that includes the full reprocessing cycle — cleaning chemistries, ultrasonic baths, autoclave cycles, repeated over years.

Direct part marking on the device itself, rather than on packaging, is what makes this demanding, because the mark must survive everything the device survives. Establishing that requires exposure testing under the actual reprocessing conditions, at the maximum number of cycles claimed, with legibility and code grade measured afterwards rather than assessed by eye.

The Documentation Set, in Practical Terms

• A mark specification defining content, position, size, and acceptance criteria as measurable properties — contrast by a stated method, or code grade to a verification standard with specified conditions — together with the durability requirement and the exposure that defines it.
• Validation records: installation qualification establishing the equipment configuration, operational qualification demonstrating the process window with its edges challenged, and performance qualification demonstrating consistent output under production conditions including material variation.
• Work instructions covering setup, operation, changeover, and what an operator does when output falls outside limits.
• Training records for operators, technicians and anyone who adjusts the process.
• A control plan stating what is monitored, how often, by what method, against what limits, and what happens when a limit is exceeded.
• Calibration records for the instruments that measure mark quality, since an uncalibrated verifier invalidates the data it produced.
• Traceability linking devices to the process records, material lots and equipment configuration in force when they were marked.
• Change control with defined revalidation triggers.

Materials Are Part of the Process

Mark quality and durability depend on the polymer, its colourant and any marking additive at least as much as on laser parameters. That makes these controlled materials within the quality system, with defined specifications, approved suppliers, incoming controls appropriate to the risk, change notification requirements, and lot traceability.

Marking additives used on drug-contact or patient-contact surfaces carry the additional burden of contact material assessment, which belongs in the design file rather than in the process documentation, and which must be revisited if the additive changes.

Change Control Is the Recurring Failure

Audit findings on marking processes cluster around change control, and specifically around changes that nobody in the organisation initiated.

A colourant supplier reformulates. A resin producer adjusts an additive package. A component supplier changes moulding conditions. None of these appear in an internal change log, all of them can move mark contrast or durability, and the notification — where one is sent — typically arrives at purchasing and stops there.

Two controls address most of it. Contractual change notification requirements with suppliers of every material that affects the process. And an internal routing rule that sends every supplier change notice for a validated material to the process owner for assessment, with a recorded decision even where the conclusion is that no action is needed.

The second is trivial to implement and is the single highest-value control in this area, because it converts an invisible external change into a documented internal assessment.

Keeping the Qualified State Real

The practical test of the system is whether the process as it runs today matches the process that was validated. Three habits keep the answer yes.

A periodic comparison of the current equipment configuration, parameters and materials against the validation record. A periodic review of the accumulated change log as a set, since individually minor changes can move a process outside its qualified state collectively. And a review of any recurring defect against the control plan and the FMEA, because a defect the system did not anticipate indicates that the analysis behind the controls was incomplete.

None of these take long. All of them find something eventually, and finding it internally is considerably more comfortable than having it found during an audit or, worse, after a device in the field could no longer be identified.

Contract Manufacturing Divides the Obligations

Where marking is performed by a contract manufacturer or an outside decorating supplier, the quality system obligations do not transfer with the work. The device manufacturer retains responsibility for the process being validated, controlled and traceable, whoever operates it.

That requires the arrangement to be explicit in the quality agreement rather than assumed. Who performs and owns the validation, and who holds the records? What change control applies at the supplier, and what changes require notification and approval before implementation? What process data and traceability records are retained, for how long, and how are they made available? What is the right of audit, and how often is it exercised? What happens to non-conforming product and to the serial numbers or identifiers associated with it?

The gap that appears most often is change control. A supplier improving their own process — new equipment, revised parameters, a different consumable — may reasonably regard it as internal continuous improvement, while for the device manufacturer it is a change to a validated process. Stating that requirement in the agreement, and confirming it is understood, is a short conversation that prevents a long investigation.

Related Reading

• IQ, OQ and PQ for Laser Marking
• When a Process Change Needs Revalidation
• Marking and Decorating in a GMP Cleanroom
• Marking Drug Delivery Devices
• UDI Laser Marking and Sterilisation

Need help with this?

The Sabreen Group provides independent engineering support for quality system documentation and validation for marking processes in device manufacture. Our engineering services team works with manufacturers on process development, material qualification and production troubleshooting. Contact us to discuss your application.

Frequently Asked Questions

Why is marking treated as a special process?

Because the property that matters — that the mark will remain legible through cleaning, sterilisation and service life — cannot be verified by inspecting the finished product. Inspection confirms the mark exists and is currently readable. Only validation establishes that the process reliably produces marks that will still be readable later.

What does UDI add to the requirement?

It makes the mark a regulatory deliverable with defined content, format and durability expectations. The identifier must remain legible for the device’s intended life, including through the reprocessing cycles a reusable device experiences, which turns durability from a quality attribute into a compliance one.

How far do supplier controls extend?

To the materials that determine the process outcome. Resin grade, colourant and marking additive all affect contrast and durability, so these are controlled materials with specifications, approved suppliers, change notification requirements and lot traceability. A supplier reformulation that nobody was told about is a recurring root cause.

What documentation does a marking process need?

A specification defining the mark and its acceptance criteria with measurement methods; validation covering installation, operational and performance qualification; work instructions; training records; a control plan defining what is monitored; calibration records for measurement equipment; traceability linking devices to process records; and change control with defined revalidation triggers.

Where do quality systems most often fail on this?

Change control, and specifically changes originating outside the organisation. A colourant reformulation or a resin additive change arrives through purchasing and never reaches the process owner, so a validated process is running on a material it was not validated with. Routing supplier change notices to the process owner closes the most common gap.

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