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Hehehe thats not bad, it has certain advantages, like probably making it easier to have the probe tip's angle to the flux at 90 degrees in more cases, and being able to easily design a feedback circuit for positive-positioning of the turning axis, anyway.
However it gets pretty weird if the sample area requirement of "1 cubic mm, +/- .25mm" is kept, as we now are talking "angular" and not "linear" increments; and a way of compensating on the fly must be be used since this creates pie-shaped "wedges" and not a square grid. Although i suppose some kind of "spiral scanning" scheme could possibly work if this can be done accurately enough (we would probably need to use a reduction gear on the turntable's Stepper to get it fine enough when reading near the outer perimeter). There would always likely be a bit of a "wedge" shape, but if the "non-linearity" is small enough it won't matter.
But several of the possible ways of "pre-plotting" a Run / Scan that i've thought of so far; that eliminate the cubic area taken up by the magnet or magnet groups so they are excluded from the plotting sequence, would probably not work in that case
As far as the body of the Plotter being a problem with interfering with the magnetic fields, it is a possibility; and that is one of the reasons i liked having it suspended over top of the target, at a fair distance (like 1.5 to 2 feet). i do not think the "X" traveling shaft can be anything but steel at least 1/2" in diameter (because it must not flex at all.. The "Y" traveling being done on precision wheel bearings riding steel tracks at either side of the unit that move the entire "X" traveling assy.), but the main frame of the thing and the legs that suspend it could be thick aluminum. Also the arm for the "z" axis, which would be the closest part to the target, can be aluminum as well... And be fairly long and thin (allowing the main body to be far enough above the target area not to interfere), since with such an arrangement the arm would be hanging straight down with a minimum of mechanical stress on it (another reason why i liked the idea of a little stepper motor driving a finely geared rack-and-pinion arrangement to move the "Z" arm up and down, is that it is probably the lightest way to do it so it doesn't put too much weight on the traveling shaft).
However it gets pretty weird if the sample area requirement of "1 cubic mm, +/- .25mm" is kept, as we now are talking "angular" and not "linear" increments; and a way of compensating on the fly must be be used since this creates pie-shaped "wedges" and not a square grid. Although i suppose some kind of "spiral scanning" scheme could possibly work if this can be done accurately enough (we would probably need to use a reduction gear on the turntable's Stepper to get it fine enough when reading near the outer perimeter). There would always likely be a bit of a "wedge" shape, but if the "non-linearity" is small enough it won't matter.
But several of the possible ways of "pre-plotting" a Run / Scan that i've thought of so far; that eliminate the cubic area taken up by the magnet or magnet groups so they are excluded from the plotting sequence, would probably not work in that case
As far as the body of the Plotter being a problem with interfering with the magnetic fields, it is a possibility; and that is one of the reasons i liked having it suspended over top of the target, at a fair distance (like 1.5 to 2 feet). i do not think the "X" traveling shaft can be anything but steel at least 1/2" in diameter (because it must not flex at all.. The "Y" traveling being done on precision wheel bearings riding steel tracks at either side of the unit that move the entire "X" traveling assy.), but the main frame of the thing and the legs that suspend it could be thick aluminum. Also the arm for the "z" axis, which would be the closest part to the target, can be aluminum as well... And be fairly long and thin (allowing the main body to be far enough above the target area not to interfere), since with such an arrangement the arm would be hanging straight down with a minimum of mechanical stress on it (another reason why i liked the idea of a little stepper motor driving a finely geared rack-and-pinion arrangement to move the "Z" arm up and down, is that it is probably the lightest way to do it so it doesn't put too much weight on the traveling shaft).
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