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Dry Metal Forming: Definition, Chances and Challenges
Frank Vollertsen,Florian Schmidt 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.1 No.1
In metal forming, lubricants are still used to prevent corrosion, to reduce friction, wear and tool load as well as to protect the workpieces and intermediates. In economic and ecological points of view, the challenge is the avoidance of lubricant usage. Within this article we define the term of dry metal forming, a technology which contributes an approach to establish green technology in mass production. Regarding this, the benefits of this technology are shown. Three different approaches exist to achieve a dry forming process: ceramic tools, self-lubricating coating systems and hard material coatings. Concerning this matter, the state of research in dry metal forming is reviewed within this paper.
Marcel Simons,Tim Radel,Frank Vollertsen 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.8
The laser chemical process is a material-removing machining process in the micro range. The process is based on a laserassisted etching process between an electrolyte and a metallic workpiece. Local overheating causes a laser-induced electrolyte boiling process, which limits the laser chemical process window. In order to reduce the laser-induced electrolyte boiling process and thus expand the process window, the laser chemical process is carried out at different electrolyte start temperatures and thus different electrolyte viscosities and surface tensions. The experimental investigations were carried out on Titanium Grade 1 with the electrolytes phosphoric acid and sulfuric acid at different electrolyte temperatures and laser powers to determine the limits of the process window by evaluating the properties of the removal cavities. As a result, the process window is extended at lower electrolyte viscosities. Thereby, the electrolyte viscosities have no influence on the geometric shape of the removal. The extension of the process window is attributed to the fact that a reduction in electrolyte viscosity results in a less pronounced formation of the boiling process, the bubble diameters decrease, and the shielding effect of the bubbles is reduced.