Effect of Slime and Dust Emission on Micro-Cutting When Processing Carbon-Carbon Composites

Abstract

Results of theoretical and experimental studies aimed at establishing features of micro-cutting with abrasive grains characterized by active emission of slime and dust particles were presented. The slime particles are just partially withdrawn from the interaction zone and partially change surfaces of the tool and the workpiece of a carbon composite material, in particular, of carbon-carbon and carbon-polymer groups.

The above materials possessing a complex of unique physical and mechanical properties are used in high-tech production though composites remain difficult to process materials. The problems manifest themselves to their utmost in making various apertures, shoulders, cutting of holes, processing edges.

The study has shown that the phenomenon of dust and slime emission in abrasive processing of carbon-based non-dense composites and plastics results from sliding fracture and cyclic weakening of the surface non-dense layer which exhibits quasi-brittle properties under the action of fast-moving micro-indenters. Conditionality of the average slime particle sizes by normal stresses in the cutting zone and the magnitude of protrusion of diamond grains above the cutting surface of the tool was revealed.

Since it was found that the particles formed during cutting are only partially withdrawn outside the cutting zone and the degree of removal decreases with an increase in the processing time, a conclusion on the cause of change in the state of the tool surface was drawn. The remaining slime and dirt change topography of the surface which results in the cutting zone temperature rise to critical values.

It was shown that the use of tools with cyclic advance makes it possible to partially improve the condition of material processing which is relevant for the implementation of the processes of ring diamond drilling, processing with diamond saw blades. It was proved that the intermittent application of areas of the diamond-bearing layer reduces the phenomenon of dirt particle sticking to the surface of the working tool. Thus, the tool stays free of dirt for longer and the machining process is more efficient.

Keywords: abrasive cutting; drilling; oscillation frequency; diamond grain; carbon-based composite material; slime; dust