How to choose the CNC tool to achieve a reduction in surface roughness

As the spindle rotation accuracy is not high and its bearing slide rail surface shape error institutions such as the motion of the beating occurred.

As the spindle rotation accuracy is not high and its bearing slide rail surface shape error institutions such as the motion of the beating occurred , the cutting process inhomogeneity and cutting materials such as discontinuities caused by fluctuations will involve cutting tool, the workpiece shift change, thus the thickness of the cutting , the cutting force or cutting width is changed , so in many cases, these factors may induce the unstable self-excited vibration from the processing system , the amplitude of the relative change in position is more enlarged , which affects knife back to eat the amount of change , so that the surface roughness increases.

It can be seen , to reduce the surface roughness , the area must be reduced residual eliminate BUE scales and spines to reduce the plastic deformation of the workpiece material and the cutting process of the vibration , in order to reduce the residual area , the tool should be compared large nose radius , the smaller angle deputy ; especially the sub angle of 0 ° wiper , very effective in reducing the surface roughness ; but wiper not too long, otherwise it will cause vibration , but the surface roughness increases, generally as long as slightly larger than the amount of feed can . In addition, there is a tool wiper wiper must ensure that the machined surface parallel with the installation , otherwise ineffective.

Rake angle generally have little effect on roughness ; But for large plastic material , the use of large rake angle of the tool is to reduce BUE scales and spines , thereby reducing the surface roughness of effective measures . For example broaching 1Cr18Ni9Ti stainless steel broaches, rake angle from 10 ° ~ 15 ° to 22 , the surface roughness can be reduced to Ra2.5 ~ 1.25um from Raum

And cutting edge flank surface roughness , roughness has a direct impact on the workpiece surface. As the tool surface roughness is reduced, help reduce friction and thus inhibit BUE scales and spines generation, therefore , the degree of growth BUE is different ; therefore all material between the tool and the workpiece material large friction coefficient, bond in serious cases, the surface roughness on bigger. When cutting carbon steel, under otherwise identical conditions , in accordance with the high-speed steel cutting tools , carbide cutting tools , order or titanium carbide -based ceramic cutting tools carbide cutting tools , workpiece surface roughness in turn decreased. But after a high-speed steel cutting tools TiN coating reduces the coefficient of friction and adhesion between the workpiece material and make BUE with barbed scales significantly reduced , thus significantly reducing the surface roughness .

Furthermore, strong wear of the tool will also increase the surface roughness ; particular boundary wear on the secondary cutting edge , on the machined surface roughness is more serious.