Chemical Focus
to short running life in case of using an aqueous cleaning agent. This would also result in high consumption and expenses for chemistry, water and energy as well as high waste management costs. Additionally the often necessary bath exchanges would reduce the availability of the cleaning machine. n Cleaning of workpieces that are difficult to dry, such as thin-walled and capillary parts, as well as stampings and bent parts. In these cases aqueous cleaning with hot-air drying would consume large amounts of energy and the process time would be much longer. n Cleaning tasks in industries such as aviation and aerospace where process approvals are based on the use of solvents to assure flawless degreasing. n Cleaning of small parts, e.g. in the electronics industry, which requires good material compatibility and a non- corrosive cleaning agent. n Intermediate cleaning steps. On the one hand, to avoid the mixture of different processing media whose removal would mean big efforts later or which in the worst case couldn’t be removed anymore. On the other hand, intermediate cleaning steps with solvents are carried out in order to minimise the amount of oily contamination brought into final aqueous cleaning processes and to extend the life span of the aqueous media. This is often the case in medical device manufacturing.
Sustainable solvent-cleaning The most common solvents in metal forming and processing industries include chlorinated hydrocarbons (CHCs) such as perchloroethylene, and modified alcohols such as Dowclene. They are characterised by good material compatibility which allows these agents to be used for virtually all types of metals. Additionally, cleaning takes place without corrosion, oxidation, discolouration, burning, dulling or other impairment of the part surface. The non-flammable, virgin
perchloroethylene Dowper MC from Safechem Europe, can be used for cleaning and degreasing metal parts with very complex geometries. It contains a special stabiliser that makes
it suitable for heavy-duty applications. Due to the relatively high boiling point of 121°C and the resulting high vapour temperature, even high-melting, oxidised or hardened grease and contaminants can be removed reliably. Additionally, Dowper MC shows minimal surface tension and is chemically very stable. Another advantage of the solvent is
its low evaporation rate. This allows for fast and complete drying of the parts, which results in short cycle times – and they are achieved in the case of geometrically very complex parts as well as of parts made of porous metals, from which trapped moisture is often difficult to remove. Thanks to the possibility of re-stabilsation an operating life of the perchloroethylene of several years can be achieved. With Dowclene 1601 Safechem offers
a solvent based on modified alcohols. It is used as an alternative for chlorinated hydrocarbons, non-halogenated hydrocarbons and aqueous media. Dowclene 1601 offers lipophilic and hydrophilic properties that enable the removal of oils and greases as well as the elimination of polar contaminations, e. g. emulsions or fingerprints, with excellent results. It is also an ideal solution when it comes to difficult applications such as cleaning of heat exchangers, micro- polished parts and expensive precision parts. Dowclene 1601 can be distilled, is non-corrosive and dries quickly and residue-free. Typical applications include cleaning prior to heat treatment, coating, welding, vacuum brazing and bonding.
Fig. 2. Virgin perchloroethylene Dowper MC is characterised by high cleaning and degreasing properties as well as a short drying time – also when it comes to complex geometries.
Fig. 3. Dowclene 1601 enables by its lipophilic and hydrophilic properties to remove polar and non-polar contaminations from complex components.
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