Your demonstration at 3:48 was so good! I'm blown away by the quality of this series that everyone can watch for free on TH-cam! What a time to be alive.
Thank you very much for sharing all your knowledge! I hope you can get those busy guys (Adam and Josh) to make more microcast podcasts! Thank you thank you thank you!
Quite nifty as always! I'm very much digging this series. & I strongly agree that Fourier anything(series, analysis, transforms & their inverses, discrete or not etc.) are among the most useful & powerful ideas ever. As they're used in engineering of ALL kinds. I'll never forget how totally blown away I was when some of these things started to really sink in. If only Jojo could see his rather simple ideas being used in our modern world as both conceptual AND actual machinery(especially software/hardware).
Regarding putting an indicator on the shinny surface and it not telling you much about error , please pass that along to used machine tool buyers. That and the five puck test on grinders both seem to get used a lot but machine dealers to sell not great machines to the uninformed
Awesome. ... now I get to beat my frustrations out of me in the gym while listening to machining ASMR😊 We use LVDTS on our massive steam control valves upstream om our main steam turbines. And our condenser bypass steam valves. Because steam flow has such a direct an big impact on Reactor power be need to have high control feedback on these valve positions.
The question at 8:17, I'm not the best as describing things, but I am fascinated by these sorts of precision videos. My guess as to at least why its not a pure sine wave is because measuring it from a fixed point, it may be in line with the center of the sphere twice per revolution, but that means it will be measuring the artifact offset from the center twice as well. Your peaks and valleys of the sine wave would be correct for a pure sine wave but the middle portion would be off more the more runout your artifact has.
Furry signals = fourier transforms ❤ What's the title/source of Bob's thesis you refer to several times? Like the 22:26 "FFT result of the 128 rev. test"
Any info on that capacitive gauge sensor? Is it available as standalone sensor with analog output or full measurement system is needed? I am looking for something in mere mortal price range. Not afraid of hardware firmware development but seems lot of theory available on net but no standalone sensor source.
Where can i learn more about how size of interferance fit effects bearing axial clereance, and how to calculate minimum shaft size depending of spindle speed? thanks:D
In regards of ADC: What about an oscilloscope? Modern, even cheap scopes have resolution of 12bits. With a hilarious degree of oversampling you'll be able to eke out extra 4 bits no problem (just make sure the memory depth is adequate). Given where you are going, my guess is you'll need a scope anyway...
You'd still have to deal with clocking the rotation, and actually doing the Fourier analysis. Sure like mine can do Fourier, but you can't selectively choose bins and IFFT. I mean the best scope I've used is only 20k so maybe a really good one can do that - but then I wouldn't be willing to bring it into the machine shop XD
@@electrowizard2000 Apparently I was not clear. I meant using a scope as an ultra-high speed, decent precision, multichannel digitizer. You just dump your perfectly synchronized readings (quadrature, rotation sensor and what not) onto your USB stick, to be analyzed on a PC.
Is there a way to dynamically compensate for these runoff errors, such as using a voice coil attached to a mass, which inputs the exact opposite force to counteract the error on the spindle? Or is this this impractical?
Active magnetic bearing spindles basically do this to keep alignment all the time with electromagnets. However unless you are working on a very high precision spindle or if you have very large predictable synchronous forces that you can cancel it is mostly impractical.
I'd imagine the data analysis would be even easier if you can set up two gauges at approximately 90 degrees offset from each other, to treat as combined complex-valued samples -- given that the FFT is a natively complex-valued concept. Though you'd probably need a preprocessing step similar to removing the n=1 eccentricity, where you put the second measurement through a linear transform that minimizes the n=2 frequency component, to cancel out the error in that sensor's relative placement.
Re: it's not pure sinusoidal - thinking out loud here - it must be due to the radius of the artifact, right? A R=0 artifact would have to be perfectly sinusoidal (obviously not realizable). A R=inf artifact would give perfect sinusoidal motion too.. Hmm. I think it's that the indicator has a small size in the insensitive direction, it isn't measuring the tangent of the artifact. As the artifact moves in that insensitive direction we get still a sensitive direction effect from the artifact's curvature. So larger artifacts would have less effect. If the runout == artifact radius R, you'd indicate at 0 and 180 are +2R, -2R as expected, but at 90 degrees you'd measure 0 (just kissing the edge) instead of the closest side being at +R because the artifact has completely moved away from the contact point of the indicator.
I think it's not purely sinusoidal because the indicator isn't always normal to the surface. If you remove all runout, the indicator is perfectly normal throughout the entire rotation (on a perfectly round artifact). However, if the artifact has some runout, the point of contact of the indicator won't be in line with the center of rotation and the center of the circle. The smaller the runout, the smaller the angular deviation from normal. I hope that makes sense, and I'm really only going off of an image in my head so there's a not-so-small chance I'm wrong.
Your demonstration at 3:48 was so good! I'm blown away by the quality of this series that everyone can watch for free on TH-cam! What a time to be alive.
Thank you very much for sharing all your knowledge! I hope you can get those busy guys (Adam and Josh) to make more microcast podcasts! Thank you thank you thank you!
I like the googly eyes on the millimess
Fourier FTW!
@@andrewharmon9839 hell yea
Highlight of my week, thanks for putting the time and thought into these vids.
@@rodfrey thanks, very glad you enjoy them
Quite nifty as always! I'm very much digging this series. & I strongly agree that Fourier anything(series, analysis, transforms & their inverses, discrete or not etc.) are among the most useful & powerful ideas ever. As they're used in engineering of ALL kinds. I'll never forget how totally blown away I was when some of these things started to really sink in. If only Jojo could see his rather simple ideas being used in our modern world as both conceptual AND actual machinery(especially software/hardware).
Awesome series! I'm making a list of all the topics promised "for later" - there is no escape.
What a fantastic lesson in measuring actual error! Bravo!
I really hope you cap off this series with a video or two showing the implementation of everything on your diamond turning lathe
Most certainly need to watch this again when all parts is out
Regarding putting an indicator on the shinny surface and it not telling you much about error , please pass that along to used machine tool buyers. That and the five puck test on grinders both seem to get used a lot but machine dealers to sell not great machines to the uninformed
I'm waiting for the collaboration project with Mr. Renzetti! This is mostly over my head, but well done!
Awesome.
... now I get to beat my frustrations out of me in the gym while listening to machining ASMR😊
We use LVDTS on our massive steam control valves upstream om our main steam turbines. And our condenser bypass steam valves. Because steam flow has such a direct an big impact on Reactor power be need to have high control feedback on these valve positions.
The question at 8:17, I'm not the best as describing things, but I am fascinated by these sorts of precision videos. My guess as to at least why its not a pure sine wave is because measuring it from a fixed point, it may be in line with the center of the sphere twice per revolution, but that means it will be measuring the artifact offset from the center twice as well. Your peaks and valleys of the sine wave would be correct for a pure sine wave but the middle portion would be off more the more runout your artifact has.
Furry signals = fourier transforms ❤
What's the title/source of Bob's thesis you refer to several times? Like the 22:26 "FFT result of the 128 rev. test"
Any info on that capacitive gauge sensor? Is it available as standalone sensor with analog output or full measurement system is needed? I am looking for something in mere mortal price range. Not afraid of hardware firmware development but seems lot of theory available on net but no standalone sensor source.
Will the theory described in these videos be applied to making new amazing parts?
Where can i learn more about how size of interferance fit effects bearing axial clereance, and how to calculate minimum shaft size depending of spindle speed? thanks:D
In regards of ADC: What about an oscilloscope? Modern, even cheap scopes have resolution of 12bits. With a hilarious degree of oversampling you'll be able to eke out extra 4 bits no problem (just make sure the memory depth is adequate). Given where you are going, my guess is you'll need a scope anyway...
You'd still have to deal with clocking the rotation, and actually doing the Fourier analysis. Sure like mine can do Fourier, but you can't selectively choose bins and IFFT. I mean the best scope I've used is only 20k so maybe a really good one can do that - but then I wouldn't be willing to bring it into the machine shop XD
@@electrowizard2000 Apparently I was not clear. I meant using a scope as an ultra-high speed, decent precision, multichannel digitizer. You just dump your perfectly synchronized readings (quadrature, rotation sensor and what not) onto your USB stick, to be analyzed on a PC.
Is there a way to dynamically compensate for these runoff errors, such as using a voice coil attached to a mass, which inputs the exact opposite force to counteract the error on the spindle? Or is this this impractical?
Active magnetic bearing spindles basically do this to keep alignment all the time with electromagnets. However unless you are working on a very high precision spindle or if you have very large predictable synchronous forces that you can cancel it is mostly impractical.
I'd imagine the data analysis would be even easier if you can set up two gauges at approximately 90 degrees offset from each other, to treat as combined complex-valued samples -- given that the FFT is a natively complex-valued concept. Though you'd probably need a preprocessing step similar to removing the n=1 eccentricity, where you put the second measurement through a linear transform that minimizes the n=2 frequency component, to cancel out the error in that sensor's relative placement.
Привет, спасибо за видео, мне очень интересна эта тема😊. Можеш сказать на какую камеру ты снимаеш?
Really good ! Thanks!
Can you just add an out of phase sine wave and adjust its amplitude to mi imize the RMS error over one rotation?
I guess the shape of the runout curve is a cicloidal. Which for small run-outs is almost the same.
Re: it's not pure sinusoidal - thinking out loud here - it must be due to the radius of the artifact, right? A R=0 artifact would have to be perfectly sinusoidal (obviously not realizable). A R=inf artifact would give perfect sinusoidal motion too.. Hmm. I think it's that the indicator has a small size in the insensitive direction, it isn't measuring the tangent of the artifact. As the artifact moves in that insensitive direction we get still a sensitive direction effect from the artifact's curvature. So larger artifacts would have less effect. If the runout == artifact radius R, you'd indicate at 0 and 180 are +2R, -2R as expected, but at 90 degrees you'd measure 0 (just kissing the edge) instead of the closest side being at +R because the artifact has completely moved away from the contact point of the indicator.
Also I'd love to see this video using a 360 degree camera algorithm using the artifact
I think it's not purely sinusoidal because the indicator isn't always normal to the surface. If you remove all runout, the indicator is perfectly normal throughout the entire rotation (on a perfectly round artifact). However, if the artifact has some runout, the point of contact of the indicator won't be in line with the center of rotation and the center of the circle. The smaller the runout, the smaller the angular deviation from normal. I hope that makes sense, and I'm really only going off of an image in my head so there's a not-so-small chance I'm wrong.
@adammontgomery7980 yeah if you used a test indicator for sure. I was thinking more the capacitive style which stays on centerline.
@@electrowizard2000 th-cam.com/video/XXdlVlzxBjk/w-d-xo.htmlsi=UMrn8q7etg7vR-cN this is the same concept.