[Dy...] Posted June 26 Share Posted June 26 So, I've been programming now a little over (2) years. I haven't had much formal training other than (2) weeks at Zeiss for the Basic and Advanced classes. Most of the knowledge that I've gained has been through YouTube, or searching forums like Reddit and Zeiss. Though we covered constraints in the Calypso advanced class, I still have difficulties wrapping my head around constraints. I guess I don't see the use if you have restricted all (6) DOF properly? Does anyone have any additional information on constraints that might be helpful? Thanks in advance! Link to comment Share on other sites More sharing options...
[Cl...] Posted June 27 Share Posted June 27 Two things they come in handy for is when reporting size and location. Say you have a very small radii segment of <90° in the XY work plane and you are reporting size, you would constrain location (X & Y). Conversely if you want to report location constrain the features radius. Link to comment Share on other sites More sharing options...
[DW...] Posted June 27 Share Posted June 27 Clark is on the money. When you constrain something in the software, you will notice the actual will become the nominal value. If you have very small portions of a feature to measure, best practice dictates constraining the size or location. Constraining either size or location is going to increase your repeatability without sacrificing the result from an unstable/small segment of a feature. Also in this scenario, you may want to switch to single points instead of scanning. Link to comment Share on other sites More sharing options...
[Mi...] Posted June 27 Share Posted June 27 You have to be careful using constraints though as basically you're making calypso pretend something is nominal. Obviously it's not, or Calypso thinks it's not. For small partial circles, Constraining Radius might help if you have to report the location. Constraining XYZ (Only 2 at a time) might help if you have to report size. To do both you would have to RFP so you have 2 circles to use... one for size one for location. I generally prefer to use other methods to help the CMM find the circle more reliably than relying on constraints. The most common way I end up using constraints is on Cylinders/Cones with a high ratio of Diameter to length, on those I will constrain "Normal Vector" almost by default now so prevent Calypso struggling with calculation Link to comment Share on other sites More sharing options...
[Cl...] Posted June 27 Share Posted June 27 Please sign in to view this quote. I like your use of constraints for cones/cylinders. I will use this going forward, thanks! Link to comment Share on other sites More sharing options...
[Mi...] Posted June 27 Share Posted June 27 Please sign in to view this quote. You can't always use it... When I say a high ratio I'm talking 50mm+ diameter with only 2mm length. Things like that are quite common in our parts. Link to comment Share on other sites More sharing options...
[Cl...] Posted June 27 Share Posted June 27 What if that scenario was reversed? The diameter was 2mm and the length was 50mm+ length? Link to comment Share on other sites More sharing options...
[Jo...] Posted June 27 Share Posted June 27 Please sign in to view this quote. I use a similar method when I want a radial distance from a "fixed" center. It helps identify the form in relation to origin, like a cam or eccentric surface. Link to comment Share on other sites More sharing options...
[Dy...] Posted June 27 Author Share Posted June 27 Please sign in to view this quote. So, in other words, you are saying if i were measuring a small feature of size where the total feature isn't available to scan, I'm telling Calypso to ignore the Actuals and report the size only from the Nominal location? Sorry if my interpretation is inaccurate, I just have to put into layman's terms for my simple mind to comprehend 😕 Link to comment Share on other sites More sharing options...
[Ow...] Posted June 27 Share Posted June 27 See if the attached helps. I put it together a few years ago for an internal class to help explain why constraining is necessary on small radius. If the topic of measuring a small radius is brought up, this will turn into a lengthy discussion like it has in the past because it seems everybody has a different perspective on it. I know it's not exactly what you're asking but, using curve is good way to measure small radius's as well and below is link to a Zeiss page that covers that. https://portal.zeiss.com/knowledge-base?id=1665954Small Radius limitiations on a CMM.pptx Link to comment Share on other sites More sharing options...
[Ch...] Posted June 27 Share Posted June 27 Thanks for sharing Owen, Hmmm, if Zeiss knows the magnification error is multiplied on radii (circles) less than a given amount (<90°), they could default to constraining this automagically in Calypso (and allow user to uncheck constraints if needed). Just a thought, I'll probably have to submit a request. 🤣 Instead of being "tribal knowledge" it would be a "standard" in Calypso. btw, yes I sue this regularly to get accurate radii sizes when needed - works well. Link to comment Share on other sites More sharing options...
[Lo...] Posted June 27 Share Posted June 27 Please sign in to view this quote. That is an awesome way to explain it. I've tried to break it down for years for people, simply. You have done that. Thank You. Link to comment Share on other sites More sharing options...
[DW...] Posted June 28 Share Posted June 28 Please sign in to view this quote. Yes. Link to comment Share on other sites More sharing options...
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