You make a valid point, but limited to something that should be and eventually will be symmetrical. I was thinking in terms of a workpiece (or assembly) of some odd shape that will have a monstrous imbalance before during and after the cut. Cutting such a part in extreme slow motion is one solution, but often that will result in an intolerably low SFM or intolerably high production time.
You would agree, methinks, that the closer you can bring the part into balance, even a very rough balance for example by bolting a bob weight to a rotating fixture or even just a face plate, the faster you can spin it for the needed operation.
I have followed this with interest and right off the bat let me say I know nothing about the physics of off balance rotating objects.
BUT I did find this explanation on the web.
What is an unbalanced wheel?
An unbalanced wheel is any device capable of repeated rotation in which
any given point along the circumference is either
A. prone to stop in a given position along that circumference as opposed to
any other, regardless of the amount of force inputed into rotating the
wheel, or
B. prone to rotate indefinitely according to the principle of having a
constant and recoverable force which acts on one half of the wheel more
than the other.
OK, presuming I understand this to mean that in an unbalanced rotation condition, the rate of rotation varies at any point on the circumference?
What I am leading up to is if you have a spindle that has an encoder, and you capture the anticipated position on several points on the circumference, due to imbalance, the following error on the spindle will vary, and the captured positions will vary.
Although Mach per-se is a bit of overkill to achieve this, if you already had, say Mach with a Galil card, Galil has a feature called high speed capture that possibly could be used with a high speed capture input, lets say you had 4 sensors on the spindle input to the high speed capture, they could be referenced off of the marker pulse so you could identify the quadrant that required the 'Bob' weight, which if the system works, could be done initially at low rpm?
Actually I just though of a method that may not need sensors, this is the use TE tell error at given positions at degrees of rotation.
Of course I could be right out to lunch with this theory, if so please ignore it.
Nosmo.
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