Abstract
This article considers the improvement of a technology of dowel-nail ballistic pointing on the basis of mathematical modeling and the development of new designs of a tool and products with new forms. Rational parameters of a tool used to produce dowels with a grooved rod have been found. The authors have shown the strain rate intensity distributions and normal stresses in cross-sections of a dowel point along the length of the deformation zone for an incomplete rolling process. Tool force variations at dowel knurling in the vertical axis line along the length of the deformation zone have been obtained. The manner of the force variations with time on both dies indicates the uniformity of the blank ponting process. Pilot production of dowels with a smooth surface of a rod has been carried out; rational parameters of a cross-wedge rolling tool have been derived. The authors have shown the possibility of import-substitution of constructional expanding dowels (anchor bolts) with their designs based on retention of an item in a pre-drilled hole in a concrete structure. A diagram has been studied and a new design of a roller-segmented-die tool has been proposed. The tool is designed for simultaneous thread-rolling and surfacing. The construction is made of a roller and a segmented die, each of the parts designed as a thread and shaping surface. The novelty of this construction lies in the fact that a shaping surface of a roller is built with several operating parts while a shaping surface of a segmented die is built with one operating part. The operating parts include pick-up and deformation zones which are made eccentrically against the tool axis, as well as a gauging zone which is arranged in line with the tool axis with a profile following the contour of the end-product. The application of the roller-segmented-die tool also enhances improvement of dowel-nail pointing efficiency if compared with flat-plate knurling. Four applications for utility models have been submitted.
Keywords
Import-substitution, dowel, modeling, DEFORM 3D software package, cross-wedge rolling, dowel-driver.
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