Electrolyte systems
ECM Technologies has been working with different electrolytes for different materials and has developed different electrolyte treatment systems.
The first generation ECM technology (1950-1990) was not making use of electrolyte cleansing technologies. The electrolyte was used till it was saturated with reaction products as metal ions, metal oxides and hydroxides and in most cases it was contaminated with the toxic Cr(VI). It was in that period impossible to machine with small gaps (<100 micrometer) as a result of the particles in the electrolyte.
By the introduction of membrane filtration systems, particles could be removed from the electrolyte by filtration. Also the pH is controlled to create a constant quality of the electrolyte, the dissolving coefficient of the metal ions is strongly depending on the pH. This value should be as low as possible for all metal ions to prevent plating of these ions to the electrode or to prevent the formation of black or brown oxides on the tool. The conductivity is an important parameter for the ECM process and is strongly depending on the Temperature. Electrolyte systems need to be equipped with a sufficient Temperature control system and electrolyte cooling to maintain a constant electrolyte conductivity.
With ECM, metal is dissolved. When alloys with a certain Chromium content are machined, it is very likely that the Chromium dissolves to the toxic and carcinogen Cr(VI). Reduction agents and other reduction techniques are known to reduce Cr(VI) to the non toxic Cr(III). Cr(III) will form an Chromiumhydroxide and will be filtered out by the electrolyte system.
By applying the above described cleansing techniques and controlling the electrolyte within specified limits it is attributing to the required quality of the part and the process. A precise and reliable ECM process requires a constant quality of the electrolyte to manufacture a constant quality of products.
ECM Technologies has gained knowledge about cleansing systems and electrolyte control. For more information you can send a request by the contactform or send an e-mail to wolters@electrochemicalmachining.com
ECM Technologies is also working on a Cr(VI) sensor to measure the Cr(VI) level in the electrolyte and to control it to a specified level. A prototype of this sensor will be available from September 2010. For more information about the Cr(VI) sensor or services you can send a request by the contactform or send an e-mail to wolters@electrochemicalmachining.com