Institute of Engineering Science, Ural Branch of the Russian Academy of Sciences (Ekaterinburg, Russia):

N. A. Babaylov, Cand. Eng., Senior Researcher, Laboratory for Applied Mechanics, E-mail: n.a.babailov@urfu.ru, babailov@imach.uran.ru

Ural Federal University (Ekaterinburg, Russia):

Yu. N. Loginov, Dr. Eng., Prof., Metal Forming Dept., E-mail: j.n.loginov@urfu.ru

CJSC Spidermash, Ekaterinburg, Russia:

L. I. Polyanskiy, Director, E-mail: info@spidermash.ru

In the work, the influence of the technological parameters for roll briquetting on the compaction coefficient and distribution of briquetting pressure along the curly generatrix of the cell cut on the roll of the briquetting press is investigated. The influence of the cell shape on the pressing roll and the size of the gap between the rolls was studied. The paper considers various forms of cells on rolls (or roll bandages) of four different types of the shapes. The purpose of the work is to describe the conditions manifestation of the so-called re-pressing of the briquette back part, leading to the appearance of cracks and destruction of the briquette according to the “dovetail” type. This phenomenon leads to a decrease in yield on the briquetting press and the formation of the return of material that must be involved in the processing of waste. A geometric model of material compaction in the cells of the briquetting press for four different shapes is constructed: pillow-shaped and three conical types. When creating the model, assumptions are made that are commonly used in the formulation of powder rolling problems. The conditions of the problem are fulfilled in a flat setting. In the model, a briquette of arbitrary shape is conventionally divided into several infinitely small volumes. The briquette formation begins in the capture section by densification of the selected volume element, the thickness of which remains unchanged until the end of the briquetting process. Plots of the compaction coefficients distribution along the direction of roll briquetting for the material for the considered cell types are constructed. The obtained data show that for the entire range of gaps between the rollers, the calculated compressibility of the briquetted material in a conical cell is higher than in a cell with a pillow-shaped shape. It was determined that the compaction coefficient in the front of the briquette is noticeably lower. To determine the plot of briquetting pressure along the generatrix of the cell, the method of standards was used, in which the dependence of the compaction coefficient on the briquetting pressure is preliminarily constructed. Then, the compaction coefficient is converted according to the compression curve for the material under study into compression forces. It is shown that to reduce the effect of re-pressing, it is necessary to increase the technological gap between the rollers of the briquetting press.
The work was performed under the theme № 0391-2016-0001 (AAAA-A18-118020790140-5) and with the partial financial support of the Resolution № 211 of the Government of the Russian Federation, contract № 02.A03.21.0006.

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