【转帖】broken dia and callou

yang686526

broken dia and callout?
there seems to be some confusion here as to the correct callout for a broken diameter.  we have a round plate with a id diameter going through the center.  this id diameter is broken by 4 slots.
is it correct to show the dimensions as "4x Ø5.00" or if its a radius as "4x r2.25"?  or can you just show the dimension without the "4x" and it is assumed the same diameter and feature?
thanks
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the dia will probably be machined as one feature and then the slots added, or machined as one feature after the slots are added, or machined as one feature at the same time as the slots. in any case, it makes most sense to dimension as 1 diameter. tolerance is tighter and if the slots leave more than 180° of the diameter, you can use positional gd&t
yes, depends on how it will be machined. mahcine one diameter, or 4 radii?
i would dim as one dia.
chris
systems analyst, i.s.
solidworks/pdmworks 05
autocad 05
you have 4 features that are coaxial. they should be shown a 4x and then the diameter. it really doesn't make any difference that the processing may only one operation (drilling as an example), one would still end up with four (4) coaxial holes.
to show that they share the same center (if you wish), reflect them in a positional tolerance using mmc but without a datum. this would reflect 4 holes in alignment.
if you wish to have the pattern of 4 holes relative to a datum(s), you could reflect them in positional to the datums.
hope this helps.
dd
i disagree, but maybe i'm not invisioning the part correctly?
ryancr, can you show us a pic of the part?
chris
systems analyst, i.s.
solidworks/pdmworks 05
autocad 05
please look up asme y14.5m - 94, top of page 148, reflecting exactly what i understand as the situation. in this case we have a composite feature control frame with 4 coaxial holes referencing datums a & b. the holes are shown 4x and then the tolerance.
if one does not want the 4 features in the pattern to a & b (bottom section of the feature control frame),look at the top of page 149 showing the 2 holes (different sizes here) relative to each other without a reference datum.
dd
how it's going to be manufactured doesn't drive design intent.....it's the other way around.  it's design intent that dictates the manufacturing process.  i think it would be safe to say that this feature(s) could be dimensioned either 4r.xxx or 4dia.xxx.  the main thing is does it meet the overall design intent and is the dimension scheme clear.
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heckler
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i interpreted the initial question as a hole broken by 4 slots that were parrallel to and intersecting the centerline of the hole. it was the radius comment and that 4 slots left 4 radii or pieces of the hole that threw me in that direction. if the slots intersect the hole perpendicular to or at an angle to the hole they would create 5 pieces of the hole.
so now i'm confused. which is it ryancr? i think we really need some kind of a picture here.
agree, a pic will help.
chris
systems analyst, i.s.
solidworks/pdmworks 05
autocad 05
wgchere is correct.
image a washer, with 4 evenly spaced id slots, which break the id diameter into 4 equal segments (the segments don't need to be equal).  
i believe that the id diameter needs to have a "4x" associated to it, but a coworker does not.
i do disagree that the way the part is manufactured should have anything to do with the dimension call-out.  two different shops may create the part in different ways.  it seems to me that there should be a standard on how this callout is shown.  i always believed that if the dia or radius was broken, that a number went in front of the dimension.
thanks,
can you please show us a pic??
see faq on how to do it.
chris
systems analyst, i.s.
solidworks/pdmworks 05
autocad 05