Cutting edge analysis of an indexable insert

Microgeometry of the cutting edge influences tool life, stability of the cutting process, chip formation, surface quality and not least heat load and force load.The form of the cutting edges is one important feature with a large influence on the machining process. The topography of the cutting edge can be captured using 3D surface metrology by Confovis. Cutting edge geometry can be derived from the surface topography as well as all characteristic parameters. 

Shape measurement using focus variation

A profile series made up of 150 individual profiles was created. The cutting edge parameters can be determined using the average profile.

R = 5.4 µm Radius of the cutting edge
ß = 67.9° Wedge angle
K factor = 1.08   This shows that the cutting edge has been protracted to the free surface.
Δr = 3.9 µm Incorrect height
Distance from the point of the upper edge to the straight cutting point
Sα = 7.2 µm  Distance from the relief point of the free surface to the straight cutting point
Sγ = 7.8 µm  Distance from the relief point of the chipping surface to the straight cutting point
 

Chipping on the straight cutting edge on the corner

A profile series with 25 profiles was created along the cutting edge. After the shape is removed, the average profile shows the chipping. The parameter Pt (total height of the profile) can be used as the dimension for the chipping.

Profile roughness of the rake surface according to standard DIN EN ISO 4287/4288 and DIN EN ISO 13565

The roughness according to standard DIN EN ISO 4287/4288 and DIN EN ISO 13565 was measured by means of confocal microscopy. The polished rake surface can only be measured with the confocal method of structured illumination.

For determining the roughness parameters according to DIN EN ISO 4287/4288 and DIN EN ISO 13565, the ripple is removed using λc= 0.25 mm Gaussian filter (for the values according to DIN EN ISO 4287/4288) or a double Gaussian filter (for the values according to DIN EN ISO 13565). The results are demonstrated in the following table:

Roughness of the surface on the cutting surface according to DIN EN ISO 25178

The cutting surface of the indexable insert indicates a chip breaker. That is why no large measurement surface can be used to determine the extensive roughness. An evaluation according to standard DIN EN ISO 25178 was carried out for the following area:

The measurement was filtered with a 2.5 µm S filter and the shape of the chip breaker was removed. A parameter table for the roughness parameters can be created with the MountainsMap at the click of a mouse button using the resulting S-F surface.