Single segment tests for the analysis of the core drilling process of concrete materials

Abstract

Diamond impregnated tools, like drill bits or circular saws, are used for the machining of mineral
materials like stones or the compound material concrete. Drill bits comprise several single diamond
impregnated segments which are attached to the top of the tool body by brazing or laser welding
processes. Fields of application of these tools can be found at the construction industry, the stone
processing and the mining industry. The segments consist of a sintered powder-metal matrix and
randomly distributed diamond grains. Hence, the number of exposed grains on the tool surface
varies even for tools of the same specification. To simplify the analysis of the core drilling process
with several segments and therefore diamonds in contact, tests with single segments were carried
out. Thus, the number of exposed grains is reduced to a manageable number. To analyse the
influence of grit size and concentration in diamond impregnated tools on the process behaviour
when machining concrete materials, path-controlled tests on a machining centre were conducted.
High performance concrete (C100) and reinforced concrete were machined and process forces
were measured to quantify the influence of the tool specification. Additional information were
gained by analysing the generated tool tracks.