Quality and technical cleanliness

Technical cleanliness gains importance, not least because of the steadily increasing complexity of production processes. A component is described as »technically clean« if it has a sufficiently low level of contamination. To achieve this, undesirable substances (contaminants) are checked and removed from the workpieces' surface to a required, agreed, or possible degree. Likewise, the condition of the component is accurately recorded. Contaminants that occur during production can be particulate or filmic. Examples include particles, chemicals, oils, greases, chips, fibers, oxides, rust, or scale.

Technical cleanliness and non-destructive testing are becoming more important in the manufacturing industry in recent years. In non-destructive testing, the quality of a component is tested without damaging or destroying the workpiece. This means that defective components can be detected quickly and removed from further processing in good time. Both methods now play a significant and success-determining role and are attracting increasing attention.


Fraunhofer IGCV examines how cleanliness requirements concerning downstream processes can gain transparency and efficiency in the future through the development of guideline values.¹ More than 40 companies from different supply chain areas were surveyed concerning internal process steps, applications, and requirements. 77 percent stated that they already carry out quality inspections to record technical cleanliness; nevertheless, there is also a need to leverage optimization potential in technical cleanliness at 63 percent of the companies surveyed. The primary consequences of inadequate technical cleanliness are considered to be a reduction in components' function and service life.

¹ Schweda, S. (2018). Sauberkeitsanforderungen für Folgeprozesse, Journal für Oberflächentechnik, 58(1), pp. 7-9.

Cleanliness analysis, quality inspection, training - our competences

Residual dirt analysis
  • Definition, analysis, and monitoring of technical cleanliness
  • Process development for the determination of coating thicknesses
Quality inspection
  • Non-destructive testing
  • Process monitoring
  • Residual dirt monitoring
  • Development of methods for process monitoring
Cleaning methods
  • Parts cleaning
  • Evaluation and optimization of cleaning processes
  • Selection, design, and implementation of cleaning processes
  • Networked information-based part cleaning (machine learning and artificial intelligence)
Continuing education
  • Consulting and training in the field of technical cleanliness
Technical cleanliness at Fraunhofer IGCV: Our competences
© Fraunhofer IGCV
Technical cleanliness at Fraunhofer IGCV: Our competences

Fields of application

  • According to DIN 8592, cleaning means removing unwanted substances (contaminants) from workpieces' surface to a required, agreed, or possible degree. The end-use or the subsequent process thereby determines the technical cleanliness.

    To clean components, Fraunhofer IGCV uses various processes depending on the cleanliness requirements. Numerous in-house cleaning systems are used, such as an ultrasonic cleaning system, blasting system, CO2 snow blasting system, low-pressure plasma cleaning, or brush wash tables. However, if we need a system that is not available in our inventory, we can fall back on a large partner network. This enables us to design application-specific solutions.

    Production-related contamination is thus efficiently minimized to be able to carry out a successful subsequent process. Examples of such contamination are oil residues that impair the subsequent welding process or oil-grease residues that affect the subsequent painting process.

    The ULTRAREIN project serves as an example of general component cleaning.

  • In additive manufacturing, we mainly deal with the processes of laser beam melting (Laser Powder Bed Fusion, L-PBF for short) and cold gas spraying (DED process). Only metals and no plastics are used as materials. Also, we deal intensively with multi-material processing.

    The big challenge here is that the material also represents the contamination. In additive manufacturing, the material particles fuse with the surface. Conceivably, not all particles have (completely) bonded with the workpiece at the end of the manufacturing process. These can become detached and thus represent contamination in the further production steps. Another challenge is the design of most components. Many are very complex in design so that the cleaning mechanisms cannot reach all surfaces within the workpiece. Current cleaning technologies already reach their limits here.

    Therefore, our goal is to use our research to analyze these structures to develop optimal cleaning processes. To do this, we develop analysis methods that check whether the desired cleaning condition has been achieved. This ensures that the powder material does not later endanger its use, cause damage to the component, or even pose health risks to employees and customers. Also, resources are conserved, money is saved, and rejects are reduced.  

    We also use technologies from non-destructive testing to monitor the quality of the component during the process. This makes it possible to directly detect defective components and remove them from the process at an early stage.

  • In battery production, we deal with various cleaning processes and the quality inspection of lithium-ion battery cells. In doing so, we examine electrode surfaces and the battery separators.

    Particulate contamination on the electrode surface of lithium-ion battery cells can be detected by active thermography. Manufacturing-related contaminations must be removed from the battery separators in a targeted, efficient, and damage-free manner. Different optical test methods do the detection of the contaminations. These methods are constantly evaluated and further developed to ensure quality in battery production.

    Information on Research Fab Battery Cells

  • Connection technology describes the constructive methods of assembling technical structures from their individual parts. Connections can be detachable, non-detachable, or conditionally detachable. Joining techniques can be classified according to physical principles: form-fit, force-fit, and material-fit.

    Our work here is particularly on the preparation of various surfaces for soldering, welding, and bonding. The surfaces must be free of contamination, such as from oils and greases. Otherwise, the weld seams may not form properly, or the adhesive may not work properly. As a result, further processing may not be able to be carried out successfully.

  • The term surface technology generally refers to all technologies that can change surface properties. In this case, the surface of the components must be adapted according to the downstream process.

    Depending on the requirements profile, the surface can also fulfill many other functions. For example, good corrosion resistance, wettability, or paintability are important.

  • Remanufacturing is the industrial process of refurbishing used products. Solutions are developed, for example, to supply motor vehicles and commercial vehicles with spare parts of the highest defined degree of cleanliness and original function in a cost-effective and resource-saving manner. The product performance made available in this way is intended to be equivalent to that of equivalent new production.

    Despite the many established fields of application, there is potential to optimize costs and quality in remanufacturing. This is often caused by the smallest impurities, impairing product quality and even leading to system failures. An example of this is engine damage resulting from insufficient technical cleanliness of a cylinder head. Examples and analyses show that the remanufacturing of old parts can save up to 80 percent of manufacturing costs in individual cases and reduce material consumption by almost 90 percent.

    Typical product segments for remanufacturing are mechanical, mechatronic, and electronic automotive and truck parts or assemblies, such as starters, alternators, engines, transmissions, and brake calipers.

    Our ASPIRE project provides further information on the design of cleaning process chains in remanufacturing.

    Bar chart: Savings potential through remanufacturing (technical cleanliness)
    © Darstellung: Fraunhofer IGCV
    Bar chart: Savings potential through remanufacturing (technical cleanliness)

Aim of our work

By integrating technical cleanliness into the production process, the desired or required product quality can be achieved.

With our work, we bring digitalization and the integration of artificial intelligence and machine learning into the cleaning process chains. With a requirement-based design of the sub-process steps, a more efficient cleaning process chain can be achieved. This not only saves costs and resources but also increases quality at the same time.

Holistic view of process chains in the field of technical cleanliness
© Fraunhofer IGCV
Holistic view of process chains in the field of technical cleanliness

Reference projects



Design of cleaning process chains in remanufacturing to optimize used components up to the quality standard of a new product.



Investigation of selected use cases from the overall additive manufacturing process chain to analyze cleaning and detection methods for their suitability for specific applications.



Development of high-throughput line production systems in additive manufacturing for end-to-end digitization of process chains.



Analysis of different methods of process monitoring with regard to their applicability in the context of mechatronic multi-material processing.



Development of a multi-sensor system to monitor the ultrasonic chain of action to increase cleaning efficiency and save energy and costs. 


Research Fab Battery Cells

Innovative production processes for battery research by means of flexibilization, modularization and sustainable use of resources.

Further projects

Here you will find an overview of various reference projects at Fraunhofer IGCV.


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