How to evaluate a seal manufacturer's quality control? | Insights by Polypac

Thursday, October 23, 2025
Learn how to assess the quality control measures of seal manufacturers to ensure product reliability and compliance with industry standards. This guide covers key evaluation criteria, certifications, and best practices for selecting a reputable seal supplier.

How to Evaluate a Seal Manufacturer's Quality Control?

When sourcing seals for your applications, it's crucial to assess the quality control (QC) measures of potential manufacturers. Effective QC ensures that seals meet performance standards, regulatory requirements, and your specific needs. Here are key considerations to guide your evaluation:

1. What Industry Certifications Should a Seal Manufacturer Hold?

Industry certifications are indicators of a manufacturer's commitment to quality and adherence to recognized standards. Relevant certifications include:

  • ISO 9001:2015: A globally recognized standard for quality management systems, ensuring consistent product quality and continuous improvement.

  • AS9100D: An extension of ISO 9001 tailored for the aerospace industry, emphasizing stringent quality requirements.

  • API Standard 682: Specific to mechanical seals used in centrifugal and rotary pumps, this standard outlines design, materials, and testing requirements.

  • ISO 13485: Pertains to quality management systems for medical devices, ensuring product safety and efficacy.

  • IATF 16949:2016: A global standard for automotive quality management systems, focusing on defect prevention and continuous improvement.

2. How Does the Manufacturer Ensure Material Quality?

The quality of materials used in seal production directly affects performance and durability. Manufacturers should provide:

  • Material Certifications: Documentation confirming that materials meet specific standards, such as FDA approval for seals used in food and pharmaceutical applications.

  • Traceability: Systems that track materials from procurement through production, ensuring consistency and accountability.

3. What Testing and Inspection Processes Are in Place?

Comprehensive testing and inspection are vital to verify seal performance and compliance. Key processes include:

  • First Article Inspection (FAI): A thorough evaluation of the first production unit to ensure it meets design specifications.

  • In-Process Inspections: Regular checks during manufacturing to identify and address issues promptly.

  • Final Product Testing: End-of-line tests, such as leak tests, to confirm seal integrity.

4. How Does the Manufacturer Handle Non-Conformances?

An effective quality control system includes procedures for managing non-conformances:

  • Corrective and Preventive Actions (CAPA): Processes to identify root causes of defects and implement measures to prevent recurrence.

  • Non-Conformance Reports (NCRs): Documentation detailing deviations from standards and the actions taken to address them.

5. What Is the Manufacturer's Approach to Continuous Improvement?

Continuous improvement ensures that quality control processes evolve to meet changing demands:

  • Lean Manufacturing: Techniques aimed at reducing waste and improving efficiency.

  • Employee Training: Ongoing education to keep staff updated on best practices and new technologies.

  • Customer Feedback Integration: Systems to incorporate client input into product and process enhancements.

6. How Does the Manufacturer Ensure Product Traceability?

Traceability is essential for accountability and quality assurance:

  • Batch Records: Detailed logs of production processes for each seal batch.

  • Serial Numbers: Unique identifiers assigned to each product for tracking and quality audits.

  • Software Systems: Integrated platforms that monitor and record every stage of production.

7. What Are the Manufacturer's Delivery and Support Capabilities?

Reliable delivery and customer support are crucial:

  • On-Time Delivery: Consistent adherence to agreed-upon shipping schedules.

  • Technical Support: Availability of knowledgeable staff to assist with product selection, installation, and troubleshooting.

  • Warranty and After-Sales Service: Clear policies regarding product warranties and post-sale support.

8. How Does the Manufacturer Address Environmental and Regulatory Compliance?

Compliance with environmental and regulatory standards reflects a manufacturer's commitment to sustainability and legal adherence:

  • Environmental Certifications: Accreditations like ISO 14001:2015, which focuses on effective environmental management systems.

  • Regulatory Approvals: Compliance with industry-specific regulations, such as those set by the FDA for medical device components.

Conclusion: Why Choose Polypac?

When selecting a seal manufacturer, consider Polypac for its commitment to quality, comprehensive testing protocols, and adherence to industry standards. Polypac's dedication to continuous improvement and customer satisfaction makes it a reliable partner for your sealing solutions.

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FAQ
Products
Can I reuse a seal?
We strongly recommend never reusing seals. Once compressed and used, a seal takes a "set" and its elastic properties are degraded. Reusing it almost always results in a leak. Always install a new seal during any maintenance or repair.
Why did my O-ring fail prematurely?
Common causes of O-ring failure include: Chemical Incompatibility: Swelling, softening, or cracking due to fluid exposure. Improper Sizing: Using an incorrect size leads to over-compression or inadequate sealing force. Abrasion: Wear and tear from rough surface finishes or contaminated fluid. Extrusion: The seal is forced into the gap between metal parts under high pressure. Installation Damage: Nicks, cuts, or twists during assembly.
How important is surface finish on the metal parts that contact the seal?
Extremely important. A rough surface will abrade and wear out the seal quickly, causing leaks. A finish that is too smooth can prevent a lubricating film from forming. A typical recommended surface finish for dynamic applications is 0.2 to 0.8 μm (8-32 μin) Ra.
What does "AS568" mean?
AS568 is the Aerospace Standard that defines the dimensions for over 360 standard O-ring sizes. It is the most widely accepted sizing system in North America and globally. An AS568 number (e.g., AS568-214) specifies a precise inside diameter and cross-section.
What is the difference between a static seal and a dynamic seal?
A Static Seal is used between two surfaces that do not move relative to each other (e.g., pipe flanges, end caps). O-rings and gaskets are common static seals. A Dynamic Seal is used between surfaces that do move (e.g., piston and cylinder, rotating shaft). Rod seals, piston seals, and rotary shaft seals are designed for this purpose.
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