[Ev...] Posted June 30, 2022 Share Posted June 30, 2022 I'm trying to get position of multiple 10-32 threads using a true pos gage. Manually probing ~8 points on the gage, then scanning 500 points on two circle paths. I'm then attempting to project the cylinder down to a plane at the bottom of the counterbore, which should create a point, which is what I would be taking additional hole positions from. My scan is shown below. The scan looks fine to me, diameter of the gage is well within tolerance. However, when I project down to the plane in the c'bore, it appears the projection is coming from what calypso is reading as the generated circle paths which is well off of where the actual scan is. This thread will be Datum B, see below, a majority of the other threads have position callouts with Datum B in the DRF. What am I missing here? Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/ Share on other sites More sharing options...
[Ro...] Posted June 30, 2022 Share Posted June 30, 2022 Looks like your Projection is backwards. The first feature is the projected feature. The second is the surface to project to. Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-47984 Share on other sites More sharing options...
[To...] Posted June 30, 2022 Share Posted June 30, 2022 You want to use an Intersection Construction. Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-47986 Share on other sites More sharing options...
[Er...] Posted June 30, 2022 Share Posted June 30, 2022 Unless cylinder length is more than the diameter, I have found scanning with lines to be more accurate. With a cylinder only 0.03 long I am not surprised at the result. Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-47988 Share on other sites More sharing options...
[Ev...] Posted June 30, 2022 Author Share Posted June 30, 2022 Please sign in to view this quote. Good catch, thanks. This wasn't the fix to the issue though. Please sign in to view this quote. Even using an intersection didn't really change anything. Instead of the software using the actual scanned points to create geometry it looks like its using auto generated circle paths. Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-47990 Share on other sites More sharing options...
[To...] Posted June 30, 2022 Share Posted June 30, 2022 Here's a thought. Go back to your projection but this time measure a circle instead of a cylinder. Like Eric said, the short length of the cylinder doesn't make a very robust axis. Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-47992 Share on other sites More sharing options...
[Ev...] Posted June 30, 2022 Author Share Posted June 30, 2022 Please sign in to view this quote. Wasn't super successful with this, if I try to measure the cylinder with anymore length i'll end up shanking out the stylus (0.3mm 😐 ). These are prototype parts, so wondering if they actually are just positionally off. Was hoping a calypso guru would be able to magically make these parts perfect Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-47994 Share on other sites More sharing options...
[Ma...] Posted July 1, 2022 Share Posted July 1, 2022 I see scanned points almost where they should be, but that cylinder and scan paths are at wrong place ( measured point are closer to model then cylinder vs. model ). Or is it bluffing my mind? Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-47996 Share on other sites More sharing options...
[To...] Posted July 1, 2022 Share Posted July 1, 2022 Please sign in to view this quote. I can't count the number of times I've tried or hours I've spent trying to figure out what is wrong with my program only to realize the part is actually out of spec. Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-47998 Share on other sites More sharing options...
[Ev...] Posted July 1, 2022 Author Share Posted July 1, 2022 Please sign in to view this quote. That's what's confusing me.. The scanned points look to be in the correct position but the scan paths are skewed for whatever reason. Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-48000 Share on other sites More sharing options...
[Ev...] Posted July 1, 2022 Author Share Posted July 1, 2022 Please sign in to view this quote. Only downside to just writing it off as 'out of spec' is that our only way to confirm this is to send the part to our customer and have them run their cmm program for verification 😕 Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-48002 Share on other sites More sharing options...
[Ch...] Posted July 1, 2022 Share Posted July 1, 2022 Are your feature nominals off? Your measured points look in the correct place. Your scan path looks off. So this might mean your feature nominals are incorrect? Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-48004 Share on other sites More sharing options...
[Ev...] Posted July 1, 2022 Author Share Posted July 1, 2022 Please sign in to view this quote. Didn't even realize I could change the nominals. Why does calypso just guestimate nominals for a scanned feature? This wasn't pulled from the CAD and it just assigns something that makes no sense. Appreciate it. Link to comment https://qualityforum.zeiss.com/topic/10082-thread-position-whats-happening-here/#findComment-48006 Share on other sites More sharing options...
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