The Mill I have is one of those BP Boss mills (R2E3 to be more specific). It runs the Erickson #30 taper spindle and it has no drawbar but rather has the operator engage a spindle brake and using a spanner to unlock the drive dogs so the tool holder can be removed.
Ok, so I have some hefty chunks of steel that I would like to machine out and the features would require me to use tooling that can get about 1.5" DOC at the bottom of the features. I decided to get some fancy 6 flute carbide roughers in the 3/4" diameter variety and take on the metal with that.
First thing I noticed and kind of figured would start showing itself; the spindle motor is only 2hp and cutting at 24ipm with a stepover of 0.040 and that full 1.5" DOC was about all the spindle wanted to handle. If I'm assuming a metal removal power consumption of 1hp per cubic inch per minute, then I am around 1.5hp already and if I would assume 80% efficiency of the system, then I am pretty much at the limit.
So, I may end up making a bunch of these things next year and my machine time would be several hours per unit with the metal removal I am getting. Since I have till the summer to make alterations, I am thinking about modifying the mill with a stronger spindle motor and ditching the vari-speed system. But, before I go and attempt that, I am wondering if the spindle would be fine with the extra metal removal I am asking out of it. Ideally, I am looking for about 3ci/min on mild steel. I would be pretty happy with that. I am just not sure if that spindle is able to handle the extra load or not. I can only imagine that the boss spindles are a little bigger than what's found on the J heads.
By the way, that 6 flute rougher end mill does not bang at all on the spindle and it cuts beautifully. The only thing I did notice was a bit of a high pitch ring coming from the end mill. I dont know if that was just because it's a brand new tool or the spindle is deflecting a little bit.
Ok, so I have some hefty chunks of steel that I would like to machine out and the features would require me to use tooling that can get about 1.5" DOC at the bottom of the features. I decided to get some fancy 6 flute carbide roughers in the 3/4" diameter variety and take on the metal with that.
First thing I noticed and kind of figured would start showing itself; the spindle motor is only 2hp and cutting at 24ipm with a stepover of 0.040 and that full 1.5" DOC was about all the spindle wanted to handle. If I'm assuming a metal removal power consumption of 1hp per cubic inch per minute, then I am around 1.5hp already and if I would assume 80% efficiency of the system, then I am pretty much at the limit.
So, I may end up making a bunch of these things next year and my machine time would be several hours per unit with the metal removal I am getting. Since I have till the summer to make alterations, I am thinking about modifying the mill with a stronger spindle motor and ditching the vari-speed system. But, before I go and attempt that, I am wondering if the spindle would be fine with the extra metal removal I am asking out of it. Ideally, I am looking for about 3ci/min on mild steel. I would be pretty happy with that. I am just not sure if that spindle is able to handle the extra load or not. I can only imagine that the boss spindles are a little bigger than what's found on the J heads.
By the way, that 6 flute rougher end mill does not bang at all on the spindle and it cuts beautifully. The only thing I did notice was a bit of a high pitch ring coming from the end mill. I dont know if that was just because it's a brand new tool or the spindle is deflecting a little bit.