[Me...] Posted May 4, 2018 Share Posted May 4, 2018 On the PiWeb report printout, an added "(M)" characteristic is added for each true position call-out. For example: If I have a true position characteristic numbered "15", PiWeb adds another true position characteristic numbered "15(M)" and it has a different result. Can someone shed some light? Link to comment Share on other sites More sharing options...
[Me...] Posted May 4, 2018 Author Share Posted May 4, 2018 This I believe is MMC. Link to comment Share on other sites More sharing options...
[To...] Posted May 4, 2018 Share Posted May 4, 2018 Thanks to Maria Haro Ritchey at Zeiss for the following explanation. --------------------------------------- PiWeb Reporting is also designed to report out statistic calculations. Because of the MMC the tolerance of the true position changes all the time. For some statistic calculation you need a fix value for the tolerance range. So we have to create a result that has a fix tolerance corresponding to the result of the flexible tolerance with MMC. On the attached example: 0.1256 is the tolerance with MMC and 0.05 is the tolerance without MMC. 0.05 / 0.1256 = 0.3980892 is 39.81 %. True position actual with MMC is 0.0020 and 39.81 % of it is 0.0008PiWeb_M_on_TP.jpg Link to comment Share on other sites More sharing options...
[Mi...] Posted May 4, 2018 Share Posted May 4, 2018 So riddle me this Batman since we are on the subject. How do I get ol PiWeb to put out a MMC on a concentricity call out?? I have looked but not really In Depth.... Any ave's to go down?? Link to comment Share on other sites More sharing options...
[To...] Posted May 4, 2018 Share Posted May 4, 2018 Click the MMC option in the concentricity. The report doesn't include the same data a the position though??? Link to comment Share on other sites More sharing options...
[Mi...] Posted May 4, 2018 Share Posted May 4, 2018 ill have to look at this closer. So much going on.... Thanks Link to comment Share on other sites More sharing options...
[Mi...] Posted May 4, 2018 Share Posted May 4, 2018 So looking at the report, something is not adding up. 46.88 (OD @ MMC) - 46.766 (Diam) = .114....(214 Bonus). Where is it getting the .194 FCF calls out Con. of 0.1 of the 46.8 OD back to A datum at MMC. So I have applied the MMC to the 46.80 OD. I have not worked with MMC and Concentricity much so here I am Am I way off base here? Link to comment Share on other sites More sharing options...
[To...] Posted May 4, 2018 Share Posted May 4, 2018 46.800 is not MMC Diameter. 46.720 is MMC Link to comment Share on other sites More sharing options...
[Mi...] Posted May 4, 2018 Share Posted May 4, 2018 I got the tolerance backwards? Its an OD of shaft. I thought the top side if the tolerance is MMC IE 46.88 (46.8 +/- .08) Am I wrong on that.... Link to comment Share on other sites More sharing options...
[To...] Posted May 4, 2018 Share Posted May 4, 2018 Oh My bad. I didn't read it correctly. Actually, I totally missed it. 😃 That is weird. Try using a standard Presentation Printout (the old Custom Printout) I'm curious it is a PiWeb issue. Link to comment Share on other sites More sharing options...
[To...] Posted May 4, 2018 Share Posted May 4, 2018 Mike, You have .080 for the concentricty tolerance. Link to comment Share on other sites More sharing options...
[Mi...] Posted May 4, 2018 Share Posted May 4, 2018 Yea u had me re thinking myself for a minute. Would we agree that my total bonus is .214 ? Im taking the .114 and adding the .1 tolerance from the FCF... Link to comment Share on other sites More sharing options...
[Mi...] Posted May 4, 2018 Share Posted May 4, 2018 yeah I noticed that.. Should be .1 on that. It has since been changed. Might be part of my issue with my figures. LOL. Ill save it for Monday Link to comment Share on other sites More sharing options...
[To...] Posted May 4, 2018 Share Posted May 4, 2018 At least you know why your numbers didn't make sense. You'll be able to sleep this weekend. Link to comment Share on other sites More sharing options...
[Me...] Posted May 4, 2018 Author Share Posted May 4, 2018 Tom, in response to your 1st answer – I understand how the (M) characteristic is calculated but I’m not understanding its’ purpose. Also, the original true position result isn’t correct. If I calculate diametrical true position using the listed X and Z numbers the result is 0.00189737. Not .0020. Even if I round up the result would be .0019. And regardless of the amount of tolerance, the features’ true position will always be this amount. Its’ just a matter of being in or out of tolerance. So I’m not understanding where the .002 comes from, and what the .0008 represents. IE: Why do I need to know what that number is? Link to comment Share on other sites More sharing options...
[To...] Posted May 4, 2018 Share Posted May 4, 2018 Jack, I'm guessing there must be some rounding going on out beyond the 4 places you're showing. In other words the .0003 and the .0009 could actually be larger, thus calculating the TP to the .002 number. That's the only thing I can think is going on. You could try increasing the number of decimal places to 5 or 6 to see if that is true. As far as the (M), it has to do with people who are running SPC. Since SPC requires you to use the tolerance in the calculation and MMC does not produce a fixed tolerance and changes with every part, the calculation for the (M) allows people to process the (M) values for their SPC. At least, this is what I understood from Maria. Link to comment Share on other sites More sharing options...
[Me...] Posted May 4, 2018 Author Share Posted May 4, 2018 After thinking about it for a while, that's kind of what I was coming up with. It's like a ratio to a fixed tolerance, like a normalizing calculation. I wonder if there's someway to turn it off? Link to comment Share on other sites More sharing options...
[To...] Posted May 8, 2018 Share Posted May 8, 2018 Please sign in to view this quote. Not that I am aware of. Link to comment Share on other sites More sharing options...
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