Multiple radius call out
Multiple radius call out
(OP)
Hi,
I have a part that has several radii in it that basically makes this long multiple radius curve, some convex and some concave. I was wondering what the best way to dimension this is. Do you dimension to the center of each radius (or the circle that makes the radius) and dimension the radius, or do you dimension to the inflection points in the curve along with the radius dimension.
I have a part that has several radii in it that basically makes this long multiple radius curve, some convex and some concave. I was wondering what the best way to dimension this is. Do you dimension to the center of each radius (or the circle that makes the radius) and dimension the radius, or do you dimension to the inflection points in the curve along with the radius dimension.





RE: Multiple radius call out
If using surface profile & basic dims I'd probably go with center and radius - but I haven't really thought about i.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Multiple radius call out
"A curved outline composed of two or more arcs is dimensioned by giving the radii of all arcs and locating the necessary centers with coordinate dimensions. Other radii are located on the basis of their points of tangency. See Fig. l-30."
That supports the point of view given above, but as worded, I don't see the language of the standard being binding (not to mention the fact that you might not follow that particular standard)
RE: Multiple radius call out
RE: Multiple radius call out
If there is some value in fully specifying the profile in 2D, making sure that radii callouts originate from their respective dimensioned center-points and using enlarged detail views might go some way towards making the drawing clearer, but I can't say how useful that might be in your case.
RE: Multiple radius call out
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Multiple radius call out
RE: Multiple radius call out
Inspection with a CMM looking at the specific inflection points seems to be of limited utility. Admittedly, I don't have a background in inspection techniques, but I feel you'd need to probe a lot more points to say with any degree of certainty that your part meets the criteria laid out in the drawing.
As far as manufacturing is concerned, if your CNC is set up using CAM software, the 3D model is probably the single most useful piece of information. My only experience is with a machine with a DRO like this
http://www.southwesternindustries.com/images/produ...
where you specify the X,Y coordinates that the tool moves between as well as the connecting radii to specify an outline, but I'm sure there are different ways to set it up
RE: Multiple radius call out
RE: Multiple radius call out