Technical cleanliness – Introduction

How important is technical cleanliness, what does it mean, what are consequences of not managing cleanliness of the product and process. We will try to briefly explain this with reference to existing state of the art both from VDA and ISO.

Technical cleanliness – Definition

Technical cleanliness is a standard in industrial production and assembly that ensures the absence of impurities that could impair further processing or function of components and systems.

Technical cleanliness is especially important for industries like automotive, aerospace, microelectronics, pharmaceutical, and medical devices.

Technical cleanliness is measured by extracting and analysing particles from the surfaces of the tested components.

Technical cleanliness can also refer to the purity of electronic components or systems of foreign particles.

Technical cleanliness – Application

The product quality can be quite sensitive to contamination.

Sometimes we can be “lucky”, and the system will fail immediately during next operation or at the customer assembly. Those instances even if disheartening are relatively quick to identify and resolve.

Unfortunately, the influence of contaminants (particles) may not always manifest itself immediately. This will then impact durability of the products / systems leading to premature failure. This will cause increase cost of warranties and in worst case scenario may lead to recall actions if affected systems are safety related.

Due to possible delayed failure occurrence of the contaminated products, it is imperative to understand the level of cleanliness that is expected from our products and be able to check if we meet those requirements.

Requirements for technical cleanliness may originate from your customer specification or GMPs for relevant products and / or manufacturing processes.

Let’s look at some examples of contamination impact on product quality for the automotive industry considering typical components as well as newcomers – batteries.

Regular components and electronics boards

1. Lithium-ion batteries production

Possible contamination with impurities or material weak points generated in cell production of lithium-ion batteries increases the risk of spontaneous internal short circuits (ISC). An ISC can lead to a sudden thermal runaway (TR) of the cell, thereby making these faults especially dangerous.

Technical cleanliness – solution, VDA 19.1, 19.2 and ISO 16232

VDA 19 series covers two areas related to technical cleanliness.

VDA Volume 19.1 Inspection of Technical Cleanliness is focusing on analysis of particles. Volume presents methods of component inspection which needs to be determined individually per different product type and expected cleanliness specification.

VDA Volume 19.2 Technical Cleanliness in Assembly is concerned with technical cleanliness in assembly – environment, logistics, personnel, and assembly equipment – and is to be viewed as a guideline.

The ISO 16232:2018 supplies “requirements for applying and documenting methods for determining particulate contamination on functionally relevant components and systems (cleanliness inspection) of road vehicles.”

ISO 16232 is based on the VDA 19. German standard differs from the ISO 16232 “in the fact that the contents are more detailed” with additional examples included in the standard. In short words VDA 19 series is more comprehensive than ISO 16232.

Article references:

VDA Volume 19.1 Inspection of Technical Cleanliness

Training materials for Skilled Assistant for Technical Cleanliness VDA 19.1

Achieving Technical Cleanliness | VITRONIC

What is technical cleanliness inspection and how is it conducted? – Noyen

Batteries | Free Full-Text | Particle Contamination in Commercial Lithium-Ion Cells—Risk Assessment with Focus on Internal Short Circuits and Replication by Currently Discussed Trigger Methods (mdpi.com)

Technical Cleanliness | VDA 19 | Automotive Manufacturing | Thermo Fisher Scientific – UK