The demands on the surface quality have increased in recent years, while at the same time higher requirements are placed on the reproducibility, traceability and resource efficiency of the processes. This requires methods adapted to the surface finish.
With the DryLyte process, Rösler Surface Technology offers an innovative solution for the electropolishing of demanding metallic components. In contrast to classic electrochemical polishing processes, automated processing with solid particles containing electrolyte takes place in a dry environment. Acid baths or process liquids are completely eliminated. In addition to a high degree of geometric accuracy and an overall improved surface result, the advantages include a reduced CO2 footprint and reduced disposal costs. The cost-intensive and complex preparation of used process liquids is completely eliminated and the workpieces come out clean from the machining process.
Surface processing faces many challenges. On the one hand, higher requirements have to be met in terms of surface roughness and geometric accuracy of the component, but at the same time the process has to meet economic and ecological criteria. Topics such as energy requirements and resource consumption as well as the avoidance of potentially hazardous substances and waste are increasingly coming into focus. In many cases, reproducible and seamlessly traceable processes are also required. With methods such as manual processing or classic electropolishing with liquid electrolytes, these requirements cannot be met or can only be met to a limited extent. The innovative DryLyte technology from GPA Innova, a partner of Rösler Surface Technology, represents an innovative solution for the reproducible processing of demanding and geometrically complex components made of conductive metals.
Sustainable and efficient grinding processes
The automated process simplifies and standardizes different surface treatments from deburring, smoothing and grinding to mirror-finish polishing and the post-processing of additively manufactured components. Depending on the initial condition of the surface and the required processing result, dry electropolishing can be used as a finishing process in combination with known vibratory finishing, blasting and other pre-grinding processes or alone.
The DryLyte technology is based on the principle of electrochemical surface removal. However, no liquid electrolytes are used for metal removal, but a large number of different sized polymer beads with an integrated electrolyte medium adapted to the application. In contrast to classic electropolishing, no harmful vapors are produced, which necessitate energy-intensive extraction and special protective equipment for the staff. Since material removed from the surface is absorbed by the electrolyte medium, no dust or metal particles get into the environment, as is the case with manual grinding and polishing processes. A stable machining result is achieved over the entire service life of the electrolyte medium.
A replacement is only necessary when the solid electrolyte is saturated due to the metal entry, for which a similar disposal takes place as with the abrasives. The degree of saturation of the electrolyte is recorded by the machine and the operating personnel are constantly informed about the condition and the remaining service life. In this way, it can always be guaranteed that reproducible results can be achieved on the component and that the electrolyte is optimally utilized. This reduces the labor and disposal costs incurred. At the same time, the CO2 footprint of the products is reduced due to the high level of resource efficiency.
Precise machining
With dry electropolishing, the fixed components move slowly through the electrolyte medium, with a homogeneous flow taking place. Depending on the component, internal processing can also be carried out, which is made possible by special electrodes. Due to the process, material is mainly removed from the roughness peaks on the surface. The material removal is therefore comparatively low and takes place very gently. The processed components have a homogeneous surface without imprints, pattern formation or orange peel effects. Even with filigree and complex geometries, there are no micro-scratches or breaks during processing.
Targeted and "controlled" processing ensures that the component geometry of precision parts, such as machine tools and tools for the pharmaceutical industry, is not changed and edges are not rounded. On the other hand, the effective smoothing of the surface minimizes the formation of cracks and craters. Among other things, this results in improved corrosion and fatigue resistance and thus a longer service life for the components. Compared to conventionally electropolished parts, dry polished parts corrode 4 to 15 times slower (the corrosion tests were carried out in a salt water solution with 30 g/L NaCl). In the case of workpieces such as gears used in mechanical systems, the treatment simultaneously improves the sliding properties due to the rapid increase in contact area and an optimal distribution of lubricants on the surface is achieved. Component wear and noise emissions are also significantly improved by better surface quality.
Another advantage of the DryLyte technology is the comparatively short process times. Depending on the application, the initial roughness and the desired result, it can take anywhere from a few minutes to 1.5 hours. The surfaces can not only be smoothed, but also polished to a high gloss in one production step. Very rough surfaces, for example of additively manufactured components, are usually prepared using an abrasive vibratory finishing process.
Versatile applications
The unrivaled and patented process was originally developed for the processing of partial dentures and crowns made of cobalt-chrome and titanium in the dental industry. In the meantime, the dry electropolishing of GPA Innova is also used for the treatment of stainless steel, steel, hard metal, nickel, aluminum and copper alloys as well as other conductive metals in other industries in which high demands are placed on the surface quality, for example in aerospace, pharmaceuticals, mechanical engineering and the consumer and luxury goods industry. In addition, due to its proven biocompatibility, it is also used in medical technology for the manufacture of implants and instruments.
The process design and definition of the process parameters are coordinated with the components and application in Rösler's Customer Experience Center. Various systems for an automated process are available for implementation. This ensures that all parts are processed with defined or validated parameters.
