Anyway, what could be happening?

The coarser the grain, the more kinetic energy, but less grain flow. Perhaps with large grains the kinetic energy is the significance variable over the DOC, but with the smaller ones the greater importance is the density of grains that making the cut.

Excuse me Sir. But you are really sure that this tendency is exact? How many repetition tests with each grain size are you make for draw this diagram?

I think that you need to use the statistical tool named power of the test.

I've taken 27 iterations at each level. Though the percentage influence as analysed using Analysis of variance is very less, I wanted to know what might be the phenomenon behind the fluctuation.

Excuse me, but the difference between DOC at 80 and 100 grain size have significance?

In another sense, and since my point of view, three grain size may be are a little bit to ensure a tendency.

Anyway, what could be happening?

The coarser the grain, the more kinetic energy, but less grain flow. Perhaps with large grains the kinetic energy is the significance variable over the DOC, but with the smaller ones the greater importance is the density of grains that making the cut.

Hi,

I think Daniel is on the right track, If you assume each cutting point on each grain is capable of removing approximately the same amount of material at any given moment, then the more grains you have in the stream the more material gets removed. With a smaller grain size you will have more cutting points in the stream until the size of the grain affects the size of the cutting points to an extent that they are no longer capable of removing the same amount of material because of point size. The obvious test is to reduce the grain size further say to 120 then 150 and see if the trend continues.

Regards,

Andy

Thank you Daniel for your insight, even am of the same thought but there are articles which suggest that the grains on their first impact on the work piece are broken into smaller grains, in that case the size of the grains is insignificant. The grain size plays a very significant role when we consider the material removal rate, but am unable to relate it to the depth of cut. And the kinetic energy approach to the solution is considerable when we reason out the first half of the trend line, but the second half is still remains unjustified.

Thank you Andrew, that's a valuable solution. I need to extend my work for finer grains and analyse whether the trend still continues.

Thank you Sir.

Dear Sir. If you want, can you upload a boxplot diagram make with all the measured values?. DOC versus grain size. With this information we can made more comments.

Thank you Sir.