ISO 7870-8-2017 PDF

Full title and description

Control charts — Part 8: Charting techniques for short runs and small mixed batches. This International Standard gives methods for applying regular variables control charts when production consists of short runs or small mixed batches and the effective subgroup/sample size for monitoring is often one; it supplies charting techniques and practical guidance to help users detect and understand process variation in those situations.

Abstract

ISO 7870-8:2017 describes ways of applying regular variables control charts to short runs and small mixed batches where the sample size for monitoring is restricted to one. It provides a set of tools for plotting and interpreting process-focused charts that can monitor similar characteristics across different items or different characteristics on the same item on a single control chart, to support better management of sources of variation.

General information

• Status: Published / Confirmed.
• Publication date: April 2017 (ISO edition 1:2017-04).
• Publisher: International Organization for Standardization (ISO); also published as national adoptions (for example BSI).
• ICS / categories: 03.120.30 (Application of statistical methods).
• Edition / version: Edition 1 (2017).
• Number of pages: 31 pages (ISO bibliographic record).

Scope

This part of ISO 7870 gives charting techniques and guidance for using variables control charts in production situations characterized by short production runs or small mixed batches where routine subgroup sampling is effectively limited to a single observation. It focuses on process-focused charts rather than product-focused acceptance criteria and addresses how to plot, monitor and interpret data when different characteristics or different items are tracked together on a single chart. The standard clarifies applicability and limitations compared with charts intended for larger subgroup sizes.

Key topics and requirements

• Methods for constructing and interpreting variables control charts when subgroup size is one.
• Charting techniques that allow monitoring of similar characteristics across different items or multiple characteristics on the same item on a single chart.
• Guidance on identifying and understanding sources of variation in short runs and small mixed batches.
• Recommendations on data plotting, limits estimation, and practical restrictions compared to standard control charts for larger sample sizes.
• Notes on when other parts of ISO 7870 apply (for subgroup sizes larger than one).

Typical use and users

Used by quality engineers, process engineers, statisticians, and production managers in industries with frequent changeovers, short production runs or many small mixed batches (for example specialised manufacturing, custom machining, small-series assembly, and some laboratory processes). Also used by consultants and trainers working on statistical process control (SPC) implementation in low-volume or mixed-product environments.

Related standards

ISO 7870 is a multipart series on control charts. Other relevant parts include earlier and related parts of ISO 7870 (for example parts covering specialized charts, EWMA charts and other charting techniques). National adoptions and related SPC guidance documents (for example BS ISO editions) may be available; see the ISO bibliographic entry and the series listing for cross-references.

Keywords

control chart, SPC, statistical process control, short runs, small batches, mixed batches, variables chart, monitoring, process variation, ISO 7870.

FAQ

Q: What is this standard?

A: ISO 7870-8:2017 is Part 8 of the ISO 7870 series; it specifies charting techniques for control charts when production involves short runs or small mixed batches and monitoring is typically based on single observations.

Q: What does it cover?

A: It covers methods for applying regular variables control charts in contexts with subgroup size = 1, guidance on plotting and interpreting process-focused charts that may combine measurements from different items or characteristics, and limits and applicability compared with charts designed for larger subgroup sizes.

Q: Who typically uses it?

A: Quality and process engineers, statisticians, production managers, and consultants working in low-volume, short-run or mixed-product manufacturing and similar environments where traditional subgroup sampling is impractical.

Q: Is it current or superseded?

A: As published, ISO 7870-8:2017 is the first edition (2017). The ISO bibliographic record shows it as published and subject to ISO review cycles; users should check national or ISO catalogs for any later confirmations or revisions.

Q: Is it part of a series?

A: Yes — ISO 7870 is a multipart series on control charts; Part 8 is one of several parts addressing different chart types and specialized techniques (other parts cover specialized charts, EWMA charts, etc.).

Q: What are the key keywords?

A: control chart, SPC, short runs, small batches, mixed batches, variables chart, process monitoring.