HellstormOP - 26-9-2012 at 09:54
Hello,
currently I am working on an alternative design of a planetary ball mill. Instead of a normal planetary gear, it should contain a normal gear, and a
steel bar with ball bearings that holds the milling jars in place. By this design, I aim to reduce the cost (planetary gears of suitable size are very
expensive) and to increase the performance (my design is dimensioned for around 1400 rpm, having the same or even a larger size than commercial
planetary ball mills, which spin max. 1000 rpm).
The steel bar/arm that holds the milling jars is rotating, while the central gear is stationary. Thus, the gears fixed to the milling jars make the
jars rotate. Now my question is: Is it generally necessary for a planetary ball mill that the milling jars spin in the opposite direction relative to
the sun wheel (in my design: steel bar) or does this not matter at all and the jars normally spin in the opposite direction because of the design of
the planetary gear? If the spinning direction doesn't matter, it will save me a gear between the fixed central gear and the gears of the jars.
Second question: What ratios need to be there regarding the spinning speed of the jars relatively to the sun wheel and regarding the radius of the
milling jars and the radius between the center of the jars and the central axis? I already tried a few basic approaches to that by comparing the
centrifugal forces created by the rotation of the milling jars around their own and the central axis, but I am unsure if this is the right way.
HellstormOP - 28-9-2012 at 12:03
So, nobody knows about the detailed working principle of planetary ball mills?
hyfalcon - 28-9-2012 at 15:21
More complicated then necessary for most purposes.
Here's a picture of what I use, fourth post from the bottom.
http://www.sciencemadness.org/talk/viewthread.php?tid=3957&a...
[Edited on 28-9-2012 by hyfalcon]
HellstormOP - 28-9-2012 at 16:40
Complexity is not an issue, as I already have an almost finished design.
HellstormOP - 30-9-2012 at 10:03
#push#