Oct 28, 2008 #1 weisusu Bioengineer Sep 19, 2008 26 What are the rules to locate which features as the primary, secondary, and tertiary datum features?
Oct 28, 2008 #2 KENAT Mechanical Jun 12, 2006 18,387 Weisusu, take a look at ASME Y14.5M-1994 section 4 assuming that's what you work to. Perhaps the most important one that sprins to mind is that they should be selected based on function.. See if any of the stuff here helps: http://www.tec-ease.com/gdt-tips.htm http://books.google.com/books?id=qv...&hl=en&sa=X&oi=book_result&resnum=9&ct=result http://www.draftingzone.com/studyzone/datums.html (you may be able to get guest membership) Again it seems you need to do some reading and hopefully get some training. KENAT, Have you reminded yourself of faq731-376 recently, or taken a look at posting policies: http://eng-tips.com/market.cfm? Upvote 0 Downvote
Weisusu, take a look at ASME Y14.5M-1994 section 4 assuming that's what you work to. Perhaps the most important one that sprins to mind is that they should be selected based on function.. See if any of the stuff here helps: http://www.tec-ease.com/gdt-tips.htm http://books.google.com/books?id=qv...&hl=en&sa=X&oi=book_result&resnum=9&ct=result http://www.draftingzone.com/studyzone/datums.html (you may be able to get guest membership) Again it seems you need to do some reading and hopefully get some training. KENAT, Have you reminded yourself of faq731-376 recently, or taken a look at posting policies: http://eng-tips.com/market.cfm?
Nov 6, 2008 #3 looslib Mechanical Jul 9, 2001 4,205 One of the things that I was taught in GD&T training was to think of the planes in the order you would mount the part in a fixture for inspection. "Wildfires are dangerous, hard to control, and economically catastrophic." Ben Loosli Upvote 0 Downvote
One of the things that I was taught in GD&T training was to think of the planes in the order you would mount the part in a fixture for inspection. "Wildfires are dangerous, hard to control, and economically catastrophic." Ben Loosli
Nov 6, 2008 #4 MadMango Mechanical May 1, 2001 6,992 Related to the original question, do the primary, secondary and tertiary datums have to follow A-B-C order? Upvote 0 Downvote
Related to the original question, do the primary, secondary and tertiary datums have to follow A-B-C order?
Nov 6, 2008 #5 looslib Mechanical Jul 9, 2001 4,205 No You can place the part on C (primary) locate it to A (secondary) and position it to B (tertiary). "Wildfires are dangerous, hard to control, and economically catastrophic." Ben Loosli Upvote 0 Downvote
No You can place the part on C (primary) locate it to A (secondary) and position it to B (tertiary). "Wildfires are dangerous, hard to control, and economically catastrophic." Ben Loosli
Nov 6, 2008 #6 MadMango Mechanical May 1, 2001 6,992 Can someone cite a paragraph reference, I get beat-up about this all the time by our wonderful QA folks. Upvote 0 Downvote
Can someone cite a paragraph reference, I get beat-up about this all the time by our wonderful QA folks.
Nov 6, 2008 1 #7 ctopher Mechanical Jan 9, 2003 17,506 A quick Google search: http://www.tec-ease.com/tips/september-98.htm http://www.mae.cornell.edu/PDF/hbv1/HBVDatums.pdf http://www.succeed.ufl.edu/papers/99/00476.pdf Chris SolidWorks/PDMWorks 08 3.1 AutoCAD 08 ctopher's home (updated Aug 5, 2008) ctopher's blog SolidWorks Legion Upvote 0 Downvote
A quick Google search: http://www.tec-ease.com/tips/september-98.htm http://www.mae.cornell.edu/PDF/hbv1/HBVDatums.pdf http://www.succeed.ufl.edu/papers/99/00476.pdf Chris SolidWorks/PDMWorks 08 3.1 AutoCAD 08 ctopher's home (updated Aug 5, 2008) ctopher's blog SolidWorks Legion
Nov 6, 2008 #8 btrueblood Mechanical May 26, 2004 10,015 Mad, See para. 4.3, at least that's where it was in the '82 std. From that para., "The desired order of precedence is indicated by entering the appropriate datum reference letters, from left to right, in the feature control frame". I.e. the OOP can vary from feature to feature. Upvote 0 Downvote
Mad, See para. 4.3, at least that's where it was in the '82 std. From that para., "The desired order of precedence is indicated by entering the appropriate datum reference letters, from left to right, in the feature control frame". I.e. the OOP can vary from feature to feature.
Nov 7, 2008 1 #9 CheckerRon Mechanical Jun 20, 2006 368 Pretty close trueblood. In Y14.5-1994, paragraph 4.4 "SPECIFYING DATUM FEATURES IN AN ORDER OF PRECEDENCE" covers it. Upvote 0 Downvote
Pretty close trueblood. In Y14.5-1994, paragraph 4.4 "SPECIFYING DATUM FEATURES IN AN ORDER OF PRECEDENCE" covers it.
Nov 7, 2008 #10 MadMango Mechanical May 1, 2001 6,992 Thanks folks, my argument is won for the day. Upvote 0 Downvote
Nov 10, 2008 #11 btrueblood Mechanical May 26, 2004 10,015 Wish my copy of 1994 std. would show up again. Upvote 0 Downvote
