HELP! With GD&T for TAPER Feature with radius.

[lkiefer]

I would really appreciated it if someone could look at the attached drawing and give me some thoughts on how so simplify this with GD&T...

I am leaning towards using a Surface profile modifier. Any thoughts will be appreciated.

 

[fcsuper]

It really depends on a lot of different factors. What is the design intent? What is functionally the most critical feature? Can you use the model itself as part of the definition? Can you use Profile tol?

Matt Lorono
Lorono's SolidWorks Resources & SolidWorks Legion

http://groups.yahoo.com/group/solidworks & http://twitter.com/fcsuper

 

[lkiefer]

The most important features are the taper size and the spherical cut size....The position between the two is also critical....The angular tolerance of the taper in relation to the centerline of the part is not as crucial, however still important...

My vendor has asked me if I can use the profile modifier to define these feature as it would be easier to inspect on the cmm...

I simply do not know exactly how to utilize that with this type of feature.

 

[restedup]

lkiefer,

The addition of datum identifiers and basic dimensions properly applied to the drawing would not necessarily 'simplify' the drawing but would lead to a more universal interpretation of your intent.

The lines labelled as C/L have no particular significance on your current drawing and are unnecessary when datum identifiers are added.

 

[fsincox]

I do not often hear, nor do I believe that most people would agree, GD&T makes a drawing simpler. It maybe so, say, if you are using general profile tolerances all over. I do think it makes a better drawing when taking into account the added feature definition. If simpler is your only criteria then you probably are there.
Frank

 

[Belanger]

I guess it all depends on what you mean by a "simple" drawing. I've seen a great number of prints that folks consider "simple" but what the prints really needed was a big red stamp that says "ambiguous."


John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[lkiefer]

Thanks everyone for the feedback....I worded this wrong in my question on...I do not want to "Simplify the drawing" what happeded here is my vendor has asked me if I could use the GD&T Profile in order to "simplify their inspection process due to the CMM"

SO my question is can I use profile of a surface to define these features and if so.....how would I represent it on the drawing?

 

[fsincox]

j-p,
I am not really against using GD&T, here. I am really on the same page as fcsuper, it is hard to apply GD&T properly if you do not know what this does or how it functions.

Surface profile can be used on anything, really. It will really come down to more of an issue of: "is it applied properly", and "is it functionally appropriate".
Frank

 

[Belanger]

Frank -- agreed!

to lkiefer: To apply profile of a surface might be fairly easy. But restedup mentioned the two important factors in his post. Any profile tolerance must be applied to a shape that is already defined with perfect dimensions. These can be displayed on the drawing as boxed dimensions (called "basic dimensions") or for complex shapes you can appeal to the CAD model for the perfect dimensions but the drawing/print should have a note stating something such as, "all undefined features are basic and are defined in the CAD model."

The other key factor is datums. A profile tolerance must have a symbol in the first compartment of the feature control frame, and a number in the second compartment. But any datum letters after that are optional. Without datum references, profile merely controls shape (and often size, too). But it wouldn't control the feature's location relative to the rest of the part. I don't know for your application if that's important to be held to the same accuracy as the shape/size.

If you choose to add datum references, doing so would "anchor" the profile tolerance zone to the bigger picture of what is important to the part. Of course, you would have to determine those datums and label them as A, B, C, or whatever. It might be tempting to call the centerline (the horizontal line in the picture) as a datum, but be careful -- you'd really want to identify the physical feature that the center line derives from as the datum feature.

Sorry so long-winded.

John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems

 

[fsincox]

I would probably use the sphere to locate the taper as the sphere's definition is simpler to define with a constuction ball like your second example. You will need more than that though, this is where function comes in. Is the middle bore of the three stepped bores a spline or something? Is this a handle for a shifter, turn signal or something?
Frank