Browsing by Author "Rabinovich, Y. I."

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    Micro-material handling, employing e-beam coatings of copper and silver
    (Southern African Institute for Industrial Engineering, 2012-05) Matope, S.; Van der Merwe, A. F.; Rabinovich, Y. I.
    ENGLISH ABSTRACT: Van der Waals forces and other adhesive forces impose great challenges on micro-material handling. Mechanical grippers fail to release micro-parts reliably because of them. This paper explores how the problematic Van der Waals forces may be used for micro-material handling purposes using surface roughnesses generated by e-beam coatings of copper and silver on silicon. An atomic force microscope, model Asylum MFP 3 D-Bio with version 6.22A software, was used to measure the forces exerted by the surfaces. A silver coating of 1.41 nm rms surface roughness value is found to exert the highest Van der Waals force, followed by a copper coating of 2.72 nm rms; a copper coating of 217 nm rms exerts the least force. This implies that, in a reliable micro-material handling system, these coatings are suitable for the interactive surfaces of the placement position, micro-gripper, and the pick-up position respectively.
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    Silver, copper and aluminium coatings for micro-material handling operations
    (Southern African Institute for Industrial Engineering, 2013-08) Matope, S.; Van der Merwe, A. F.; Rabinovich, Y. I.
    ENGLISH ABSTRACT: Micro-material handling has challenges accompanying it because of adhesive forces, which make the picking and placing of micro-parts difficult. The adhesive forces hinder the picking of a micro-part, and once picked, they pose even a greater challenge when attempts to release a micro-part are made. Van der Waals forces are part of the adhesive forces and are always present between interacting surfaces in a micro-material handling operation. However, Van der Waals forces can profitably be manipulated in a micro-material handling operation. The paper reveals how the Van der Waals forces can be advantageously used in micro-material handling operations involving silver, copper and aluminium coatings of rms surface roughness values ranging from 0.5 nm to 2.72 nm, which are produced by the electron beam evaporation (e-beam) method. These were found to exert Van der Waals forces ranging from 17 nN to 314 nN, which can be used for reliable micro-material handling operations.