I like the idea of having Datum D be represented by the two holes, I think I would do a composite tolerance there to control orientation tighter than location. My only hesitation with this method would be someone (vendor) making the part mis-interpreting it to be that Datum D is the one hole...
Meaning the planes defined by B and C are oriented to the planes defined by D and E. In other words right now if you draw a line between B and C and another line between D and E the angle between the lines is 0. In real life that won't be the case, right?
I'm making my head hurt because I think i'm making something harder than it needs to be.
I have a Circuit board that interfaces with a heatsink through two pins (part of the heatsink) with a hole (Datum B) and slot (Datum C defined by the width). There is a pattern of holes (two Ø.118 and 4...
I understand how simultaneous requirements would keep the holes and pocket together during inspection but I don't see how a composite tolerance would allow me to tighten the relationship between the holes and pocket while keeping the relationship back to DEF somewhat "looser". Unless you guys...
What if on that same angled face (with the holes) I had a pocket which I wanted to control back to A B C but also control a little tighter with respect to the holes. What's my best route here? Do I setup another set of datums with the holes and then profile the pocket to...
Forgot View A, added to make it a little easier to see the entire picturehttp://files.engineering.com/getfile.aspx?folder=a208cc9c-34d1-45b8-a19b-89cb60882ff9&file=combined2.JPG
Good idea... See attached.
Datum B is a hole
Datum C is the width of the slot
http://files.engineering.com/getfile.aspx?folder=6f94cd82-2497-4e9b-9fd0-e8cbab89db9a&file=combined.JPG
Thanks for the feed back guys.
Datum c is meant to be the short dimension of the slot
The box bolts down on datum a and is aligned to the mounting surface by two pins which go into the hole and slot datum b and c respectively
I was trying to stay away from adding more datums but i see your point
View B attached:
Sorry if there is a better way to do this...http://files.engineering.com/getfile.aspx?folder=dc181664-bbff-43c0-8bfb-a263842ed066&file=ViewB.JPG