Why are the requirements for technical cleanliness always increasing?
Because parts and components are growing increasingly more complex and smaller, limited by ever-shrinking tolerances, and exposed to greater loads, while the maintenance and inspection internals are continuously being extended.
What is meant by technical cleanliness?
The cleanliness of technical components according to defined contaminant limiting values. Contamination such as from dust, dirt, particles, fibers, or grease and oil films on a part, component, complex systems, or surfaces that could cause functional failure or surface imperfections.
Which standards and norms are applicable for technical cleanliness?
ISO 16232 parts 1-10, VDA 19.1 Residual Dirt Analyses, VDA 19-2 Assembly Cleanliness, ZVEI Technical Cleanliness in Electrical Engineering.
Which analytical procedures are described by VDA 19.1?
1. Standard analysis with gravimetry and/or light-optical analysis
2. Extended analysis methods (process optimization, cause research like SEM / EDX, LIBS, Raman and IR-spectroscopy, light-optical determination of particle hight and microcomputer tomography
3. Shortened analysis (is used in detailed coordination between customer and supplier)
What is meant by an extraction procedure?
Removing particles from parts and components This is described very well in VDA 19.1 and also in ISO 16232.
What extraction procedures are there as a rule?
According to VDA19.1, they include injection, ultrasound, rinsing, agitation, dissolving (preparation before extraction procedure), air extraction (air jet extraction/air throughflow extraction)
What areas are the most common sources of contaminants, and where are the greatest risks of contamination located?
Production and assembly processes, contaminants from packaging materials, particle carryover from personnel, and environmental effects.
How are clean areas and clean rooms classified and grouped?
According to VDA 19.2, the areas are divided up into so-called cleanliness levels SaS0-SaS3. SaS0 = unregulated area, SaS1 = clean zone, SaS2 = clean room, SaS3 = very clean room.
What does the CCC code mean?
The CCC code is a classification system for cleanliness limiting values and usually stipulated on drawings and order specifications. CCC stands for component cleanliness code; see under ISO 16232.
What is meant by a dispersibility diagram?
In VDA Vol. 19-2 Assembly Cleanliness, “dispersibility diagram” is portrayed to help in selecting a suitable room concept to counteract the ability of particles to disperse.
What is a particle trap?
So-called particle traps, set up and activated at various working heights, are used for determining the environmental contamination of specific working areas during a defined period of time. A particle trap has a sticky surface on which particles and other types of contaminants settle. The surface of the particle traps is subsequently analyzed in a laboratory, and the values are logged.
How is the testing frequency established?
Based on our experience, decisions and considerations related to analytical results that involve maintaining limiting values, or even when these are exceeded, must always be based on a trend evaluation. Increasingly more OEMs and large-scale T1 suppliers in the automobile industry also share this view. That is why a defined escalation procedure has been established in many factory standards. Testing frequency is oriented to the respective “contamination level” in production or assembly. To this end, it is necessary to conduct and evaluate multiple analyses from different production and assembly batches. It is on the basis of these results that warning and intervention limits are to be determined and the testing frequency established.
What does blank value mean?
The blank value is the quantity of contamination originating from the “basic contamination of the cleaning equipment.” This needs to be determined and duly noted for every sampling in order not to generate false results from the extraction actually taken from the components.
What is meant by a decay curve?
The decay curve is a qualification measure to determine and confirm the correct extraction method and its setting parameters.
What is a Basic Clean Check?
Basic Clean Check refers to a method developed by TopQM Systems back in 2007 for the purpose of determining the actual quantity taken from production and assembly processes with respect to the existing level of cleanliness and portraying the optimization measures in a purposeful and meaningful way. Many companies use it to launch a targeted “cleanliness offensive” in order to face the challenges of increased customer demands in a structured and systematic manner. It is extremely important to regard the entire process and logistics chain and to incorporate it in the risk assessment.