IQ, OQ, PQ Process Validation for Medical Silicone Components

IQ, OQ, and PQ are three stages commonly used to qualify a manufacturing process. In medical device supply chains, they help show that a process is installed correctly, works across a defined operating range, and can repeatedly produce acceptable parts under normal production conditions.

For medical silicone components, this matters because final inspection may not reveal every risk. A molded valve can look clean but be under-cured. A respiratory seal can pass a visual check but fail compression recovery. An overmolded part can appear bonded but separate after aging. Process validation is used when quality must be built into the process, not sorted in at the end.

This article explains IQ/OQ/PQ from the point of view of custom medical silicone parts: what the terms mean, when validation is needed, what customers usually expect, and how to avoid a validation package that looks complete but does not control the real risk.

What is IQ/OQ/PQ?

IQ means Installation Qualification. It verifies that the production equipment and supporting systems are installed as specified and ready for their intended use.

OQ means Operational Qualification. It asks: can the process make acceptable parts at defined operating limits or worst-case conditions?

PQ means Performance Qualification. It checks whether the approved process repeatedly makes conforming parts under the conditions used in routine production.

For medical silicone parts, IQ/OQ/PQ is usually needed when the finished part’s quality cannot be fully verified by later inspection or testing alone. The validation depth should be risk-based. A sterile fluid-path seal, valve, or tubing connector may need a much stronger package than a non-critical external accessory.

What Customers Want to Know

People searching for IQ/OQ/PQ usually want practical answers, not just definitions. The real questions are often:

• Do we need process validation for this medical silicone part?
• What is the difference between IQ, OQ, and PQ?
• How many runs, lots, cavities, or samples are needed?
• What should be included in the protocol and report?
• Which parameters should be challenged during OQ?
• What makes a PQ run representative of production?
• What changes require revalidation or partial requalification?
• What should the supplier provide, and what remains the device manufacturer’s responsibility?

Start with the component’s function and the consequences of failure. Then assess what inspection can reliably verify. Those findings guide the validation scope within the customer’s quality system.

Before IQ: Define the Validation Baseline

Before writing the protocol, establish the approved design and material specification. Define the critical characteristics and how each will be measured against its acceptance criteria. The baseline must also identify the production cavities and explain how lots will be traced and packaged.

A finished silicone part does not reveal every manufacturing risk. Its cure state or bond strength may depend on processing conditions that cannot be judged from appearance. Establish the production route and inspection method before formal validation; while those are still changing, the team is generally still characterizing the process.

When Validation Is Needed

Consider validation where inspection alone cannot reliably establish conformity. For silicone parts, curing and bonding can create properties that are difficult to verify without destructive testing. Later handling and packaging may also affect requirements such as cleanliness.

Examples include:

• incomplete cure or cure variation
• internal voids, bubbles, or weak areas
• weak overmold bonding
• unstable compression set
• contamination or particle risk
• flash on a sealing edge
• dimensional movement after post-cure
• surface treatment or coating variation
• cleanliness or packaging conditions that cannot be fully verified afterward

If the defect can be fully detected by final inspection with a reliable method, validation may be lighter. If the defect cannot be detected without destructive testing, long aging, or use in the final device, the process needs stronger control and evidence.

Regulatory and Quality Context

For medical device manufacturing, process validation is tied to the idea that special processes must be controlled when the output cannot be fully verified by later monitoring or measurement.

In the United States, FDA’s Quality Management System Regulation became effective on February 2, 2026 and aligns 21 CFR Part 820 more closely with ISO 13485:2016. FDA also publishes process validation guidance that is written mainly for drugs and biological products, but its lifecycle thinking is still useful: understand the process, qualify it, and keep monitoring it during routine production.

For component suppliers, the practical rule is straightforward: the validation plan should follow the device manufacturer’s quality system, risk file, customer requirements, and applicable regulations. A supplier can provide evidence, but the finished device manufacturer usually remains responsible for deciding what validation is required for the device application.

Validation Roles and Responsibilities

The customer or device manufacturer usually defines the intended use and validation strategy, and gives final approval. The supplier provides evidence about how the process operates and how production is controlled. Responsibilities for deviations and change notification should be agreed before work begins.

This division matters because IQ/OQ/PQ can fail as a project even when the molding data looks acceptable. If the customer has not defined the critical function, acceptance criteria, measurement method, and approval route, the supplier may generate records that are technically tidy but not useful for the medical device file.

IQ: Confirm the Setup

IQ is the foundation. It confirms that the manufacturing system is installed and ready for controlled production before process studies begin.

For medical silicone manufacturing, IQ may cover:

• equipment identification, model, serial number, location, and approved use
• injection molding machine, compression press, oven, mixer, vacuum system, trimming equipment, or packaging equipment records
• mold identification, cavity count, revision, surface finish, parting line, venting, and approved drawing revision
• utility checks for electricity, compressed air, cooling water, vacuum, temperature control, and environmental systems
• calibration status for sensors, timers, scales, durometers, calipers, vision systems, gauges, and test fixtures
• software version, recipe control, user access, and data retention for controlled equipment
• approved work instructions, inspection plans, packaging instructions, and traceability methods
• material storage, lot control, shelf-life control, and segregation of medical-grade silicone compounds

If the component requires controlled cleanliness, IQ should also cover the production environment, post-molding handling flow, packaging area, and environmental monitoring records that are part of the validated process.

OQ: Challenge the Process Window

OQ confirms that the process can produce acceptable parts across the approved operating window. The team normally defines nominal settings, upper and lower limits, and any worst-case combinations before OQ begins. Acceptance criteria, sample plan, measurement method, and reaction plan should also be agreed before parts are run.

OQ should not be used as uncontrolled process optimization. If the team is still discovering the basic settings, the process is not ready for formal OQ. Trial work can be useful, but formal OQ should challenge a process window that the team already understands well enough to defend.

For LSR injection molded medical parts, OQ may review:

• A/B material ratio and mixing quality
• barrel, nozzle, runner, and mold temperature
• injection pressure, injection speed, shot size, holding pressure, and cure time
• cold runner or valve gate behavior
• demolding condition and part deformation risk
• flash, short shot, bubbles, knit lines, surface defects, and critical dimensions

For compression molded silicone parts, OQ may review:

• compound weight and preform preparation
• mold temperature, pressure, closing speed, venting, and cure time
• overflow and flash condition
• part removal method and deformation risk
• post-cure time and temperature when required
• dimensional stability after cooling, aging, or post-cure

For overmolded components, OQ should examine whether the approved insert preparation and bonding method work throughout the proposed process window. Confirm that inserts remain correctly positioned and assess bond strength using the agreed test method.

OQ should establish an operating window supported by test results. Identify the parameters that require control and set any necessary alarm or action limits. The evidence must show that parts meet the specification at the challenged conditions.

PQ: Prove Routine Production

PQ confirms that the process performs repeatedly under routine production conditions after IQ and OQ are complete. It should represent the way the part will actually be produced, inspected, packaged, labeled, and released.

PQ should reflect routine production rather than a specially managed demonstration. Use the normal production rate and approved work instructions, with operators performing their usual duties. Include the specified inspection and packaging steps. Some customers request three successful runs or lots; the protocol should justify the number against the risk and customer requirements.

A PQ plan for medical silicone components often includes:

• approved production equipment and released tooling
• production operators trained to approved work instructions
• normal raw material lot control and traceability
• standard production speed, cure condition, demolding method, post-cure process, inspection plan, and packaging method
• one or more production runs or lots as defined by the approved protocol, often with multiple runs for higher-risk components
• sampling that covers cavities, shifts, operators, material lots, and critical dimensions where applicable
• acceptance criteria for dimensions, visual quality, hardness, physical properties, functional testing, cleanliness, labeling, and packaging

Begin PQ only after the manufacturing baseline is established. Changes to the design or process during the study can make its results unrepresentative of the production route being qualified.

How to Define the Validation Scope

The validation scope should be built from the part’s real function, not from the product name alone.

Validation needs depend on what the component does in the device. A silicone seal in a breathing path may need different evidence from the same material used on a non-contact housing. Define that function before deciding what to test.

Useful scope questions include:

• What is the component’s function in the medical device?
• What could happen if the component fails?
• Which characteristics cannot be fully verified by final inspection?
• Which process inputs affect those characteristics?
• Which features need cavity-level or lot-level evidence?
• What sample size and acceptance criteria are justified by risk?
• What change would make the old validation no longer representative?

This is where FMEA, design review, and early supplier review become useful. They help turn a generic validation request into a focused validation plan.

Silicone Project Parameters to Review

Medical silicone validation should focus on parameters that can affect safety, function, or consistency.

Important items include:

• Material control: silicone grade, hardness, colorant, catalyst system, supplier certificate, lot number, shelf life, and material change control.
• Cure condition: mold temperature, cure time, heating balance, post-cure condition, and evidence that the part is not under-cured.
• Dimensional behavior: shrinkage, cavity variation, critical sealing dimensions, flash thickness, trimming effect, and post-cure dimensional movement.
• Cleanliness: production environment, handling, washing if used, drying, bagging, packaging, particle control, and bioburden-related customer requirements where applicable.
• Functional performance: sealing pressure, opening pressure, compression set, pull force, bonding strength, flow behavior, or tactile feel depending on the part.
• Inspection method: gauge suitability, visual defect criteria, measurement repeatability, sampling plan, and acceptance criteria.
• Traceability: material lot, machine, mold, cavity, operator, production date, inspection record, and packaging lot.

For higher-risk medical projects, the customer may also request aging data, sterilization compatibility, extractables and leachables review, or ISO 10993 biological evaluation. These requirements are product-specific and should not be assumed from the raw silicone material alone.

Documentation

A useful validation package should make it clear what was validated, why the evidence is acceptable, and what future changes would require review.

Common documents include:

• validation master plan or project validation plan
• risk assessment and critical process parameter review
• IQ protocol and IQ report
• OQ protocol and OQ report
• PQ protocol and PQ report
• approved drawing, specification, material requirement, and inspection plan
• equipment, mold, fixture, gauge, and calibration records
• training records for operators and inspectors
• material certificates and lot traceability records
• in-process and final inspection data
• deviation records and corrective actions, if any
• final validation summary and approval
• change-control requirements after validation release

The records must identify the part and drawing revision, then link them to the material and production setup used in the study. Include the approved inspection methods and acceptance criteria. This makes it possible to assess whether later changes are covered by the original evidence.

Maintaining the Validated State

After PQ approval, routine production must continue to follow the validated process. Maintain the equipment and train operators to use the approved instructions. Inspection and material records help detect changes, while deviations require documented review and action.

Review any change that could affect the validation evidence before releasing further production. Replacing equipment or repairing a mold may alter the process, as can changes to the compound or post-cure cycle. Updates to inspection and packaging also need assessment. The review determines whether partial requalification or revalidation is necessary.

Conclusion

IQ, OQ, and PQ help turn medical silicone manufacturing from a trial-based activity into a controlled production process. IQ confirms that the setup is ready, OQ challenges the process window, and PQ proves that normal production can repeatedly meet the specification.

An effective validation plan starts with the part’s function and tests the process risks that could prevent it from meeting requirements. Its records should make the approved conditions clear enough to reproduce and provide a basis for evaluating future changes.