[pa...] Posted January 23, 2023 Share Posted January 23, 2023 Hello all, I have a .020in wide slot to probe (self center probing single points). I fear I will break the very thin styli (.45mm shank x .5 in long). Is it ok to use a 20 mN measuring force? The tolerance is a .015in profile and I can live with a .001-.002 imprecision. The calibration tells me a .0008 S value, can I trust this value with such a small measuring force? Probing dynamics is 50%. Thank you Link to comment Share on other sites More sharing options...
[To...] Posted January 23, 2023 Share Posted January 23, 2023 Test it with a ring gage. Link to comment Share on other sites More sharing options...
[pa...] Posted January 23, 2023 Author Share Posted January 23, 2023 The context is not the same though, since the part I am probing is a baked metal injection molding process part and there is no risk on the ring gage of detecting false points like in the narrow slot with rough sides I'll try that for sure anyways, thank's Link to comment Share on other sites More sharing options...
[Ri...] Posted January 23, 2023 Share Posted January 23, 2023 Please sign in to view this quote. I'll let someone else chime in, but I would think that you would need to get the head specifically tuned for that low of a measuring force. I know the software will allow you to set it that low, but honestly I don't even know if it is measuring that low. The spec sheet shows 50mN as the lowest value. Can you give more details about your styli? a 0.45mm diameter shank isn't as brittle as you think it is. You say it is 0.5" long (12.7mm), but is that the length of the shank or the overall length of the styli? You have a slot that is 0.5mm wide. You would need a probe much smaller than 0.5mm. I'd personally set Probing Dynamics lower than 50%. But remember that Probing Dynamics is just the factor of the speed it approaches the surface from the Retract Distance. If you have a very low Retract Distance, you will hardly notice a difference. I've measured tiny surfaces with tiny probes before with great success. Your Sigma Value sounds high, but you are using too many different units, so I don't know if that is Metric or Inches. High for Metric, and unacceptable for Inches. Link to comment Share on other sites More sharing options...
[Mi...] Posted January 23, 2023 Share Posted January 23, 2023 Unit conversion complicates answering your question. We use many 1mm dia. probes ranging from 17mm to 30mm in length, both M5 on XT and M3 on XXT machines and to be perfectly honest most of the time the probing force is left at default, on XXT we sometimes have to use Sensitive. XT we just slow down the feature, and use any of the various methods available to help find small features/holes. Missing bore/Material detection, Secondary alignments, Measurement Ref, etc. I don't think setting the force that low is your answer. Link to comment Share on other sites More sharing options...
[pa...] Posted January 23, 2023 Author Share Posted January 23, 2023 Please sign in to view this quote. Hello again. The .45mm shank (only) is 9.5mm long. The ruby was removed in order to reach the bottom of the slot. We are probing in direction of the shaft only, not sideways and we care less about precision here. The Sigma is high for that reason. Thank's again Link to comment Share on other sites More sharing options...
[pa...] Posted January 23, 2023 Author Share Posted January 23, 2023 Please sign in to view this quote. What is that spec sheet? I don't know about it and I would like to get it if possible. Link to comment Share on other sites More sharing options...
[Ri...] Posted January 23, 2023 Share Posted January 23, 2023 Please sign in to view this quote. I'm super confused. Why would you remove the ruby?? A CMM is not a height comparator. Please buy a 0.3mm styli in order to reach the bottom with an actual stylus. Link to comment Share on other sites More sharing options...
[Ri...] Posted January 23, 2023 Share Posted January 23, 2023 Please sign in to view this quote. Link to comment Share on other sites More sharing options...
[pa...] Posted January 23, 2023 Author Share Posted January 23, 2023 Please sign in to view this quote. It is because the slot is too deep, we would shank on the second bigger shaft that is used to hold the 0.3mm ruby. The tiny shaft right next to the 0.3mm ruby is very short. So yes, for that sequence, no need for usual CMM precision, we use the CMM because it is already measuring other features on the part. Link to comment Share on other sites More sharing options...
[pa...] Posted January 23, 2023 Author Share Posted January 23, 2023 Ok, I have measured a "perfectly" flat surface with a flatness tolerance, both with a ruby probe at 100mN et our new shank with ruby removed at 20mN. I end up with almost the same results, .0002 apart. It is fine for us. I also measured a wider slot with the same 2 stili, same conditions for each and I got the same results. I guess it's good enough for that specific job. Thanks a lot for the comment, but if someone can forward the document were it states a measuring force of 50mN minimum. Thanks again! Link to comment Share on other sites More sharing options...
[Th...] Posted January 23, 2023 Share Posted January 23, 2023 If you have access to the Zeiss Portal, there's a list of documents you can download from it. Any of the tactile sensor categories will link to the contact sensor manual. All the specs are in there.sdp.PNG Link to comment Share on other sites More sharing options...
[pa...] Posted January 24, 2023 Author Share Posted January 24, 2023 Please sign in to view this quote. Oh thank you so much, I have just downloaded the document and I see the "0.05 to 1 N / continuous" for the Vast Gold. Link to comment Share on other sites More sharing options...
[Da...] Posted January 26, 2023 Share Posted January 26, 2023 Are you qualifying the probe without the ruby?? what type of qualification are you using? Link to comment Share on other sites More sharing options...
[pa...] Posted January 26, 2023 Author Share Posted January 26, 2023 Please sign in to view this quote. Yes, with 50mN force, 30% dynamics, spherical calibration. I know it doesn't make sense but cylindrical calibration does not work for whatever reason. We obtain a sigma of .0007. Link to comment Share on other sites More sharing options...
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