In the wrong place, even the lightest contamination can have dire consequences - from a large number of production rejects, through costly reworking, right up to production stoppages.

Technical cleanness requirements for workpieces are increasing sharply, with no end in sight. But there is no magic formula for achieving precisely defined residual soiling values on the surface of components; each cleaning task needs a specific solution. Factors determining process choice include materials, contaminant, component geometry, degree of cleanness required (both film and particulate soiling), and production throughput.

Companies in engine and gear manufacture have used individual part cleaning for many years, as the geometries and strict cleanness requirements make targeted treatment of channels, boreholes and surfaces necessary. There’s also a trend towards individual part cleaning in other parts of the automotive supply industry, driven by stricter cleanliness requirements as well as avoidance of damage from parts handling.

The increasing level of automation in modern manufacturing should prompt increased use of individual part cleaning, providing the process can run inline; optimum workflow depends on matching and intergrating the various manufacturing and intermediate cleaning steps. Individual part cleaning is also set to increase where it offers logistic advantages, for example if downstream processes require components to be in a specific position. Batch processes also have potential here, as they offer the advantage of high throughput for mass-produced parts, and thus represent a lower proportion of the total production costs for a workpiece.

Functional surface cleaning

The targeted cleaning of ‘functional surfaces’ and component sections - such as sealing surfaces, laser-welded surfaces or pre-assembled and preserved parts - with CO2 snow jet, laser or plasma processes - is currently a niche sector. However this will become increasingly important, due to the often drastically different cleanness requirements of workpieces - for example the need for a specific surface quality of defined parts or sections for downstream processing steps.

In such cases, classic water-based or solvent-based cleaning can often be very costly, as the entire component has to be cleaned to the strict standard of the functional section. As cost pressure in manufacturing processes increases, targeted functional surface cleaning offers time and cost savings; and if it can be integrated into the manufacturing process, the clean surface can be provided ‘just-in-time’ eliminating any measures to keep parts clean after cleaning and during transport.

Easy-to-handle cleaning fluids

Fluids, solvents and water-based fluids will continue to be important, and the economic and ecological requirements of the user will help determine which solutions are used. The easiest to handle are those used in multi-stage or combined cleaning processes, such as immersion cleaning, ultrasonic treatment and injection flood washing. With water-based fluids the trend is towards solutions that can remove heavy soiling at low temperatures. This means shorter treatment times, and conserves energy and water.

With solvent-based cleaning, the introduction of polar solvents has helped make processes faster and easier. These fluids can remove both non-polar soiling, such as grease or oil, and polar contamination, such as water-based coolants and lubricants, salts, burrs and other particulate material in a single wash. Cleaning fluid treatment is also set to become increasingly important; matched filtration and separator systems extend the useful life of the cleaning fluids, increasing the quality, profitability and environmental friendliness of the parts cleaning process.

Cleanness tests becoming more important

Cleanness checks of material surfaces are now significant in quality-oriented manufacturing. Non-destructive methods of analysis with high accuracy and reliability are needed to check the cleanness of surfaces on components and functional areas. These methods must also be able to work fast, preferably at full production speed, to allow deviations from specified values be detected quickly. Trends in plant and process engineering; the direction of developments in cleaning fluids; methods of analysis allowing the effectiveness of cleaning processes to be checked both efficiently and reliably in terms of residual particulate and film soiling - all are addressed at parts2clean, the Trade Fair for Cleaning in Production from the 28th through the 30th of October in Stuttgart.

www.parts2clean.de