Abstract
Cutting tools with carbide inserts operate under harsh conditions that can cause cracking and failure, as their strength directly depends on the stress-strain state. The study was conducted to determine of the influence of the angle of installation in the holder of brazed carbide plates of cutting tools on their stress state was investigated. Experimental studies using the method of photoelasticity are characterised by high sensitivity, non-destructive effects, clarity, and speed of results. The study was carried out on the polarisation-projection unit PPU-7 using physical models of carbide plates made of optically sensitive material ED-6, which were attached to the holder with different installation angles. The resulting isochrome and isokline photographs made it possible to assess the actual visual picture of the existing stresses. During the experiment, the cutting tool models were loaded using a specially designed stand that simulated the cutting force. The principal stresses were calculated by the method of difference of tangential stresses for the selected insert installation angles. It was proved that the angle of attachment of the carbide insert to the holder undoubtedly affects the distribution of stresses in it during metalworking. A quantitative relationship has been established between the angle of attachment to the holder and the magnitude of internal stresses acting in the carbide plate. The highest stresses σequ occured in the cross-section of the cutting blade of a carbide insert regardless of the angle of attachment to the holder. The lowest level of acting stresses along the measurement points in three zones along the width of the carbide insert when attached to the holder at an angle of -30° was found. With connection angles of 15°, 0°, and -15°, critical stresses occur in all investigated areas across the width of the plate along the measurement points