Meet high cleanliness requirements efficiently

Topic of the month

In many applications, the cleaning of components is a production step that is critical to quality; an optimal solution to this problem requires a suitable product and expertise. When removing non-polar and partly as well polar impurities, solvents such as chlorinated hydrocarbons and modified alcohols are able to achieve high cleanliness requirements in a reliable, efficient and sustainable manner.

When cleaning parts used in the medical industry, DOWCLENE 1601 achieves biocompatible surfaces in accordance with DIN ISO 10993-5, 2009. © Photo: SAFECHEM Europe GmbH

"Equal solves equal" - according to this principle, solvents such as chlorinated hydrocarbons and modified alcohols are the preferred choice for non-polar impurities such as machining oils, greases, waxes and resins.

They are characterised by good material compatibility, so that parts made of virtually any metal can thus be cleaned. At the same time, cleaning is carried out without corrosion, oxidation, chemical burning, matting or other alteration of the surface.

But which solvent is best suited for a particular application? To answer this important question, SAFECHEM Europe GmbH, a subsidiary of The Dow Chemical Company, considers the entire production environment on the one hand because substances carried into the solvent bath play a crucial role.

On the other hand, the CHEMAWARE laboratory services including solvent analyses and oil compatibility tests support the decision process and the optimal combination of the service elements.

The cleaning of complex sandwich and monolithic composite structures prior to bonding is critical to the quality. Therefore, DOWPER MC perchloroethylene is used. © SAFECHEM Europe GmbH

Cleaning using chlorinated hydrocarbons

As a result, for example, DOWPER MC is being used at Gebrüder Kunze GmbH, an important German automotive supplier. This solvent is a virgin, specially stabilised perchloroethylene which has been developed for difficult cleaning tasks and for degreasing metal parts that have a high degree of soiling.

The company produces millions of net shape parts made of steel, stainless steel and aluminium; during their cleaning and degreasing process, a lot of oil is carried into the solvent bath, including chlorinated oils. Due to the distillation process, acids can be formed over time, which may result in corrosion of the cleaning equipment and a reduced solvent lifetime.

To prevent this, SAFECHEM conducted oil compatibility tests with various stabilisers. The stabilisers used are thus optimally aligned to the oil, so that the solvent can achieve a lifetime of several years.

DOWPER MC is also certified for many cleaning applications in the aerospace industry. Aircelle Ltd., a member of the SAFRAN Group uses this solvent for example to clean complex sandwich and monolithic composite structures prior to bonding when manufacturing engine nacelles. The company decided for DOWPER MC based on extensive cleaning tests.

DOWCLENE 1601 and the COMPLEASE Chemical Leasing model are the optimal solution for the cleaning of components for manufacturers of innovative heat exchangers © Photo: SAFECHEM Europe GmbH

Modified alcohols - a versatile alternative

With the distillable solvents from the DOWCLENE 16 series SAFECHEM and Dow have developed modified alcohols which have lipophilic and hydrophilic properties. They are used as an alternative to chlorinated hydrocarbons, hydrocarbons as well as aqueous cleaners.

This includes, for example, the cleaning of complex heat exchanger components at HS Marston Aerospace Ltd., a UTC Aerospace Systems company. HS Marston produces innovative heat exchangers and fluid management systems, which are used in commercial and military aircraft as well as in motorsport and in the electronics industry.

The decision for DOWCLENE 1601 was based on extensive cleaning tests and laboratory analyses. Due to its special formulation the solvent can reliably and reproducibly remove both, non-polar impurities such as oils and greases as well as polar substances such as cooling emulsions and solids like salts and abrasion particles.

In addition to the approval for cleaning applications in the aerospace industry by well-known companies, parts cleaned with DOWCLENE 1601 have been certified by the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) to be biocompatible for medical applications in accordance with DIN ISO 10993-5, 2009.

The DOWCLENE 1621 cleaning liquid was developed for flood and vapour degreasing in combined solvent/aqueous cleaning processes © Photo: SAFECHEM Europe GmbH

DOWCLENE 1611 is a solvent based on modified alcohols with stronger hydrophilic properties. Applications include for example the cleaning of lapped and sintered parts, the removal of adhering polishing pastes, abrasion, and the cleaning of aqueous cooling and lubricating emulsions. The DOWCLENE 1621 cleaning medium was developed for flood and vapour degreasing in combined solvent/aqueous cleaning processes.

It is used, for example, by Germany's leading contract hardening shop Schwäbische Härterei Ulm GmbH (SHU) in a hybrid cleaning system. SHU often misses information about the type and amount of the contaminants on the parts to be cleaned. At the same time, the demands for cleanliness are very high, especially in thermo-chemical diffusion processes such as nitrifying and nitrocarburising.

SAFECHEM offers additional service elements, such as test kits, for all chlorinated solvents and modified alcohols. These enable to easily control the quality of the solvent on site. If necessary, suitable stabiliser concentrates for the re-stabilisation of solvents are available.

CHEMAWARE Solvent Analyses and Oil Compatibility Tests assist in the thorough selection of the right solvent and contribute to process reliability and cost-effectiveness. © Photo: SAFECHEM Europe GmbH

Virtually emission-free operation

Fresh solvent is supplied in the SAFE-TAINER System and used solvent is taken back for professional recycling. In combination with closed cleaning equipment, this safety system developed by SAFECHEM is considered to be the Best Available Technology (BAT) for the safe and sustainable transport, storage and handling of solvents. Special accessories enable practically emission-free solvent cleaning.

Chemical Leasing - a future-oriented solution

Companies from different industries such as the aerospace industry, automotive suppliers and contract cleaners, value the COMPLEASE Chemical Leasing model developed by SAFECHEM as a future-oriented alternative for solvent cleaning. It focuses on the performance of the solvent which is optimised by accompanying services in order to meet the high cleaning requirements of customers towards quality, environmental responsibility and efficiency.

Customers benefit by using less solvent and stabiliser while the cleaning process and the results are being optimised. At the same time users get support from specialists who have long-time experience and deep knowledge about the cleaning process. Due to the fixed monthly leasing fee COMPLEASE customers can exactly calculate their cleaning costs.

DOWPER™ MC, DOWCLENE™, COMPLEASE™, SAFE-TAINER™ and CHEMAWARE™ are trademarks of The Dow Chemical Company ("Dow") or Dow-affiliated companies.