The 3rd edition of VDA 19.1 - What will be new?
The change in mobility, as well as general technological developments in the automotive industry, are not leaving existing standards untouched. Technical cleanliness is also being challenged by new requirements in the course of the shift towards e-mobility, assistance systems and autonomous driving, as well as by general trends in technical cleanliness. A revision of VDA 19.1 is therefore now essential for testing technical cleanliness.
Under the leadership of the Fraunhofer Institute for Manufacturing Engineering and Automation IPA, the TecSa 3.0 industry association has been working on a revision of VDA 19.1 over the past two years. Revision 3.0 has now been produced as a manuscript and will soon be transferred to the yellow print phase. The final edition of VDA 19.1 2025 is expected in November 2025. Today, at least the main objectives and changes of the new edition are known, which we would like to summarize below.
What are the new requirements for technical cleanliness?
The shift towards e-mobility and assistance systems is increasingly confronting technical cleanliness with new issues. The revision of VDA 19.1 is therefore aimed in particular at these new requirements:
- New damage mechanisms (short circuit, clearance and creepage distances, contact resistances, damage to insulation layers, optical blockage, etc.).
- Cleanliness specifications geared towards damage mechanisms (conductivity, hardness, etc.)
- Small particles (< 50μm) (cameras, sensors)
- Dry process chains
- Complex systems with consistent cleanliness limits (HV systems)
- Large and heavy components and testing of functional areas instead of entire components (e.g. battery trays)
What are the main objectives of the revision?
In principle, the structure of VDA 19.1 with its chapters and sub-chapters is to be retained as before; new topics will be integrated into this structure so that references from other documents can largely be retained. Implementation in management or inspection documentation therefore does not represent a major effort.
Since the first edition of VDA 19.1 20 years ago, technical cleanliness has become an established quality feature for the majority of components and systems in the automotive industry. As a result, the testing of technical cleanliness by cleanliness laboratories has also increased significantly and the now large number of laboratories at manufacturers and service providers requires various clarifications and adjustments to trends in order to ensure the comparability of the tests.
The new edition should therefore also precisely describe the fully standardized test procedure - from packaging and delivery of the test specimens to standard-compliant evaluation - and thus avoid any further uncertainties in the customer-supplier relationship. However, VDA 19.1 is also intended to describe the framework conditions for free, case-specific tests.
General information on the cleanliness test method
The purpose of cleanliness inspections can be differentiated for different cases:
- Verification of cleanliness limits: The cleanliness specifications defined as a quality feature in the customer-supplier relationship are checked and documented with the cleanliness test. The specific requirements and parameters for reliable verification are precisely specified in VDA 19.1. For example, the sufficient extraction effect must be verified by means of decay measurement. The “limit value test” with defined or agreed parameters is used here.
- Monitoring for process control: Test methods that provide a large number of results in a short period of time with as little effort as possible and reveal process changes are suitable for this purpose. The requirements for standard tests are generally not applied here. In the previous context, these are “shortened analyses”
- Root cause analysis: As a rule, more specific information on particles, such as the material, is required here. The test methods here usually deviate from the standard test or extended analysis methods such as SEM/EDX or IR analyses are required. These are “advanced analyses”
As a standard, the cleanliness test consists of three stages:
- Extraction of the particles: The particles are detached from the component using liquid cleaning medium, air or adhesive stamps.
- Separation of the particles: The loosened particles are deposited onto a “sample carrier”, the analysis filter or particle trap.
- Analysis of the particles: The analysis filter or particle trap is analyzed optically or using SEM/EDX with regard to quantity, size and material.
Extension of the areas of application and validity
VDA 19.1 will now provide two ways of testing cleanliness limits:
- Standard test for maximum comparability:
With defined start parameters for extraction, analysis filter and standard analysis that can be used without further agreements in the defined application area. - Free test for special questions:
With flexibility in parameters, analysis filter and analysis. These must then be coordinated in the customer-supplier relationship.
Extension of the test methods
The expansion of the test methods takes particular account of the new requirements from the field of electromobility. However, normative gaps in liquid test methods that have been practiced for many years are now also being closed.
Dry extraction
In addition to classic liquid extraction, dry extraction now plays an important role with the inclusion of new dry extraction methods. The previous “air extraction” with blowing off and flowing through is being replaced by dry extraction and now also includes suction and the stamping test in addition to these classic methods.
- Suction now extends the test spectrum, especially for large and bulky components. The test parts do not have to be placed in a chamber or basin during suction extraction and can therefore be extracted without transportation to a cleanliness laboratory.
- The stamping test enables the simple testing of partial surfaces whose cleanliness is specified and can therefore also be carried out directly in production.
Liquid extraction - low-pressure rinsing
In addition to the previous “pressure-rinsing” method, low-pressure rinsing has been added to liquid extraction. In contrast to “pressure-rinsing”, where the cleaning effect is significantly supported by the impulse of the jet, the dissolving effect in low-pressure rinsing is only achieved by the liquid running off the surface. Up to now, low-pressure rinsing has been used in practice with open extraction equipment, i.e. open extraction systems or glassware, because the rinsing pressure specified in VDA 19.1 (starting parameter volume flow 1.5 l/min) is not practicable for this. This means that the previously practiced low-pressure rinsing with < 1 l/min volume flow is now described in the standard. However, the methods are not comparable due to the very different cleaning effects and must be selected specifically and documented accordingly in future.
The analysis - extended criteria and methods
In view of the increasing importance of fibers and particles < 50 µm, the following criteria and methods are being expanded:
Fiber length:
It is often not the individual fiber, but the total quantity of fibers that is functionally critical. It is also not possible to control the fiber length of individual fibers in the process, but only the total amount of fibers. The new criterion “total fiber length” as the sum of the stretched lengths of the individual fibers will make it possible to regulate the total quantity of fibers in the future.
Free light optical analysis:
In addition to standard light-optical analysis for dark and metallic particles >50 µm on white analysis filters, free light-optical analysis now describes the detection of particles <50 µm or light-colored and low-contrast particles. This chapter provides exemplary approaches for the targeted analysis of these special features.
SEM/EDX analysis:
Here too, the SEM/EDX analysis is now described in detail as a standard analysis with defined settings and defined material classes for particles >50µm. Therefore, this SEM/EDX standard analysis does not require any coordination in the customer-supplier relationship. If there are deviating issues, e.g. particles <50 µm or other particle materials, including organic materials, the free SEM/EDX analysis will also provide a framework here.
Conclusion
The 3rd edition of VDA 19.1 brings significant innovations and adjustments that meet the current and future requirements of the automotive industry. In particular, the consideration of new damage mechanisms and the introduction of specific cleanliness requirements for small particles and complex systems represent decisive advances. The expansion of the test methods to include dry extraction procedures and the adaptation of the analysis criteria to the new requirements of modern automotive technology underline the importance of technical cleanliness as a quality feature. Overall, the revised VDA 19.1 provides a solid basis for ensuring technical cleanliness in the changing automotive industry and contributes to improving the reliability and safety of modern vehicles.
Newsletter registration