ISO 12308:2017

Overview

ISO 12308:2017 - Plain bearings: Quality assurance of sample types - defines the types of plain bearing sample types exchanged between purchaser and manufacturer and specifies their intended applications, manufacturing process, testing and documentation. It is focused on series production contexts such as internal combustion engines where different sample types (prototype, initial, reference, etc.) are needed for development, approval and ongoing quality control.

Key topics and requirements

• Defined sample types (symbols S1–S6):
  • S1 - Fitting sample: for fitting tests (dimensions only).
  • S2 - Prototype sample: for functional tests and performance development (complete quality testing; quantity typically ≤ 200).
  • S3 - Intermediate sample: partially produced using series processes; used in pilot lots (quantity typically ≤ 20); later replaced by initial samples.
  • S4 - Initial sample: produced under series production conditions to prove conformance (quality characteristics per ISO 12301; quantity typically ≤ 20).
  • S5 - Reference sample: represents desired values for quality characteristics; supplied to purchaser for control tests.
  • S6 - Characteristic modification sample: produced after a specification modification; only affected quality characteristics are tested (quantity typically ≤ 20).
• Inspection and test reports: Manufacturer must supply a completed test report with sample data on dimensions, material and/or performance. The purchaser should share inspection results; test records are retained as agreed.
• Marking: All sample deliveries must be clearly marked as samples by agreement between manufacturer and purchaser.
• Designation: Samples can be designated using the ISO 12308 code (e.g., “Sample ISO 12308 - S4” for an initial sample).

Practical applications

• Use during design validation, pilot production, and production release of plain bearings for engines, gearboxes and other mass-produced machinery.
• Establishing specifications (dimensions, materials, performance) and demonstrating supplier capability before mass production.
• Routine supplier-to-purchaser exchanges for receiving inspection, reference comparisons and targeted re-testing after design changes.

Who should use this standard

• Plain bearing manufacturers and suppliers
• OEMs (automotive, engine and gearbox manufacturers)
• Quality engineers, inspection labs and purchasing departments
• Product and process development teams involved in series production

Related standards

• ISO 12301 - Plain bearings: Quality control techniques and inspection of geometrical and material quality characteristics (referenced for testing requirements).
• ISO 9000 and ISO 3534 - For general quality management and statistical terminology guidance.

Keywords: ISO 12308:2017, plain bearings, sample types, quality assurance, initial sample, prototype sample, reference sample, testing, ISO 12301.