Creation of Datum Centerplane in a Wedge (flat taper) shape
Creation of Datum Centerplane in a Wedge (flat taper) shape
(OP)
I have a symetrical wedge shaped part and am trying to apply the correct standards for creating a datum plane for it, alot like a V-Block mentioned in other threads. If this were a part with parallel sides I would have a "feature of size" and all would be well, however the taper has seveal dimensions to contol its size and form. Placing the datum on the Basic Angle dimension alone would leave some ambiguity.
Plan A) I apply datum targets (three)to each face of the wedge effectively creating a center plane for which a Datum Feature Simulator could me fabricated. From this plane I will contol position of holes that need to be related to the center of the part.
Plan B) Apply symmetry correctly.
The use of symmetry gets a lot of discussion in various posts, and I would love some feedback as to prevailing use of datum centerplanes in V shaped features.
Thanks,
Jferg
Plan A) I apply datum targets (three)to each face of the wedge effectively creating a center plane for which a Datum Feature Simulator could me fabricated. From this plane I will contol position of holes that need to be related to the center of the part.
Plan B) Apply symmetry correctly.
The use of symmetry gets a lot of discussion in various posts, and I would love some feedback as to prevailing use of datum centerplanes in V shaped features.
Thanks,
Jferg





RE: Creation of Datum Centerplane in a Wedge (flat taper) shape
Or is the functional datum really the mounting holes or some such?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Creation of Datum Centerplane in a Wedge (flat taper) shape
The GDT was not applied well originally and the holes are skewed for lack of correct contol. The holes need to be true position of 0.25mm to wedge centerplane. This part starts life as a casting which also had lack of control for the resultant profile of the wedge faces. I'm concerned that without post machining those faces, applying datums to the faces could create a plane that is not truly centered as well.
Thanks!
RE: Creation of Datum Centerplane in a Wedge (flat taper) shape
Thanks
RE: Creation of Datum Centerplane in a Wedge (flat taper) shape
1. do you care about the tip width varying between the 5.35 and 5.10 as you go from one end to the other?
2. making one side of the wedge flat and controlling the other with an angularity tolerance could be another way to do it. (I always worry that a datum target point I call out may just happen to be at a local depression or peak that may not represent most of the surface, but this may be no different than setting a flat surface on a datum simulator and letting the high points speak for the rest.)
RE: Creation of Datum Centerplane in a Wedge (flat taper) shape
RE: Creation of Datum Centerplane in a Wedge (flat taper) shape
It is not.
If you have an access to Y14.5-2009 book, check out Para. 4.3, especially part (g) and Fig. 4.3 (g) respectively.
The standard allows you to use “complex shape” as a datum and Fig. 4.3 (g) looks very much “wedge-like”.
Standard recommends using Profile to control the wedge itself, and your setup “embracing” the part with datum targets is up to the task.
All together, your redline looks perfectly fine to me. It may need some polishing (I couldn’t find what datum B is), but definitely not illegal.
RE: Creation of Datum Centerplane in a Wedge (flat taper) shape
RE: Creation of Datum Centerplane in a Wedge (flat taper) shape
CheckerHater: Thanks as well, I meant to use the tip dimension with a datum identifier (plane) attached like a slot is against the rules because it alone does not define the shape. I don't have a copy of the 2009 version but my 1994 version
has par 4.67 which shows a highly irregular twisted shape.
Im pretty confident they way I have it will work, thanks for the feed back. Any comments on symmetry?
RE: Creation of Datum Centerplane in a Wedge (flat taper) shape
RE: Creation of Datum Centerplane in a Wedge (flat taper) shape
The goal is to specify the hole axes to be congruent to the wedge shape. The resultant wedge shape(from casting) must be used to define the center plane to which the holes get their reference.
Thanks
RE: Creation of Datum Centerplane in a Wedge (flat taper) shape