Overview
ISO 12302:2017 - Plain bearings - Quality characteristics - Statistical process control (SPC) defines which dimensional quality characteristics of plain bearings can be regulated and controlled using statistical process control (SPC). It applies to most plain bearing types (except thick-walled half-bearings) and focuses on variables (measurable dimensions), explicitly excluding attribute-type inspections. ISO 12302:2017 is intended to be used alongside ISO 12301 and supports manufacturers and customers in establishing SPC-based production control for plain bearings.
Key topics and requirements
- Scope and focus: Covers dimensional variables for plain bearings; attributes (qualitative pass/fail) are not addressed.
- SPC methods: The specific statistical techniques to achieve process control are not mandated - methods are to be mutually agreed between the manufacturer and customer.
- Selection of characteristics: Clause 5 requires manufacturers and customers to select which quality characteristics will be subject to SPC, based on intended function and application.
- Geometric quality characteristics: Clause 6 provides a matrix classifying characteristics as preferred (“yes”), optional (“(yes)”), unsuitable (“no”), or not relevant (“-”) for different plain bearing types. Typical dimensional characteristics listed include:
- Wall thickness and outside diameter
- Inside diameter and width
- Flange diameter, flange thickness, and flange perpendicularity
- Line and point measurement tolerances, crush height, straightness, etc.
- Material quality characteristics: Clause 7 notes that material-process control depends on process knowledge; manufacturers determine which material parameters should be monitored statistically to meet customer requirements.
- Documentation and agreement: The standard emphasizes agreement between manufacturer and customer on which characteristics and SPC methods will be used.
Applications and users
- Manufacturers of plain bearings - to define SPC programs for production control and process capability monitoring.
- Quality engineers and process engineers - to select dimensional characteristics for statistical monitoring and to implement control charts and sampling strategies.
- Purchasing and procurement - to specify SPC requirements in supplier agreements and technical orders.
- Inspection and metrology teams - to align measurement plans with SPC-controlled characteristics.
Practical uses include establishing control charts for critical bearing dimensions, reducing process variability, demonstrating ongoing compliance, and improving first-pass yield for bearing production.
Related standards
- ISO 12301 - referenced normative standard for plain bearing quality control techniques and inspection of geometrical and material characteristics.
Keywords: ISO 12302:2017, plain bearings, statistical process control, SPC, quality characteristics, dimensional variables, ISO 12301.