Analysing a photo of a mechanical cam

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Discussion Overview

The discussion revolves around the analysis of a mechanical cam from a linotype printing press using an image. Participants explore methods to extract angular displacements, velocities, and accelerations from the image, as well as software options for obtaining coordinate data for further analysis.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about software that can extract coordinates from a 2D image of a cam, suggesting that approximately 500 coordinates could provide a good approximation for analysis.
  • Another participant mentions that a CAD program, specifically Alibre Design Xpress, can import 2D .dxf files into 3D and suggests it might be useful for the analysis.
  • A different participant questions the feasibility of obtaining angular information from a single image, suggesting that multiple time-coded images or operational measurements might be necessary for accurate analysis.
  • One participant proposes using a scale and calipers to take measurements from a scaled-up image, emphasizing the importance of reliable scaling for accuracy.
  • Another participant recommends "spotlight," a freeware created by NASA, but questions whether real-time analysis is needed.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of extracting detailed angular information from a single image, with some suggesting alternative methods and tools while others remain skeptical about the accuracy of such an approach.

Contextual Notes

There are limitations regarding the assumptions about the image scaling and the reliability of measurements taken from a single image. The discussion does not resolve the technical challenges involved in analyzing the cam.

peterAustralia
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hi all

I have an image of a mechnaical cam from a linotype printing press.

I want to get angular dispalcemetns, angular velocities and angular accelerations of this cam from the image.

Is this possible. Does anyone know any software where I can get an image and then get a set of coordinaates of the perimeter for analysis. My rough guess says that if I had 500 or so coordinates I could get a very good approximation of the cam.

so is there any software out there that can get me the coordinates I seek. Is there other software in existence which I can use to analyse the cam. Since this is a 2D image, perhaps a CAD program could analyse the coordinates if they were in dxf format of possibly csv?

my background is coding and web design. This is for a friend who has been working on this 'project; for almost a year and going mad. (yes he has a lot of spare time!). Thus the finer points of mechanical cam analysis and software are actually lost on me

thanks in advance if you are able to help
n peter evans
 
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peterAustralia said:
...perhaps a CAD program could analyse the coordinates if they were in dxf format of possibly csv?

I'm unsure about the analysis part, but http://www.alibre.com/xpress/software/alibre-design-xpress.asp" will import 2D .dxf 's into 3D & its free.

GL hope it helps.
 
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I don't see how you are going to get all of that information from one image of the cam. Do you have multiple images that are time coded or something along those lines?

Is this cam in operation right now? If it is, is there any way one could install even a simple prox probe to take some measurements?

I have, from time to time, used a simple scale with an image to reverse engineer something, but you have to make sure that the scale the photo was taken at is reliable and verifiable. If you had that, then pretty much any 2D CAD package will import an image to work on top of.
 
Tough one. I'd probably be getting the image scaled up, getting it on a drawing board, and using calipers to take measurements at indexed points from the centre at as many positions as possible. Then plot out distance against angle in Excel or some such.

The rest is just a case of some mathematics, but I'm not sure how accurate your initial measurements would be.
 
Check for "spotlight", freeware created by NASA. Do you need to to real time analysis??
 

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