Profile on a unit basis

[AMontembeault]

ASME Y14.5 - 2009 specified in section 8.3.3.2 that profile could be specified on a unit basis (as a note to the section). In the 2018 version of the standard, this reference has been omitted from the comparable section and there is seemingly no reference permitting profile on a unit basis anywhere. I can't tell if this is an accidental omission, or an intentional deletion.

Part of me wants to accept the practice as a logical extension of the principles, but I was wondering if there might be any good arguments as to why it shouldn't be used and may have been intentionally deleted, which might make me reconsider. Thoughts?

 

[3DDave]

It appears intentional as the related function is now replaced with an explicit callout of the transition between two different profile tolerance widths.

See Figure 11-13 Nonuniform Profile Tolerance Zone With Zones to Smooth Transitions and
Figure 11-14 Nonuniform Profile Tolerance Zone Alternative Practice

Also

11.3.2.2 Zones to Smooth the Transitions. Figure 11-8
illustrates abrupt transitions that occur at the transition
points B and C when different profile tolerances are specified
on adjoining segments of a feature. A nonuniform
profile tolerance zone may be used to smooth the transition
areas. See Figure 11-14.

Note: I think they f'd up the 11.3.2.1 reference in Figure 11-13 and the Figure 11-14 reference in 11.3.2.2

It does not appear to remove the potential for a step in the outline, it just removes the step in the tolerance zone for which they do not specify a blending function.

Gotta do baby steps rather than analyze the entire problem in one go.

One day they will discover how using measurement and control of curvature would be a huge help.

 

[jassco]

Hi, AMontembeault

I don't see section 8.3.3.2 in ASME Y14.5 - 2009. Do you have a different version of the standard?

Best regards,

Alex

 

[3DDave]

11.3.3.2 is in 2018.

8.2.2.2 is in 2009.

Seems like a typo by AMontembeault

 

[Burunduk]

Non-uniform tolerance zones have nothing to do with a tolerance specified per unit length or area, they don't perform the same function.

 

[3DDave]

Non-uniform tolerance zones have nothing to do with a tolerance specified per unit length or area, they don't perform the same function.

In section 8.3.2.2 Non-Uniform Zones to Smooth the Transitions

NOTE: A profile per unit length, similar to that shown in Fig. 5-4
for the control of straightness, may be used to control abrupt transitions
that occur when profile tolerances are specified on adjoining
segments of a feature.

Looks like the committee disagrees.

Also, my own typo sneaked in there, it's not 8.2.2.2, it is 8.3.2.2 in 2009.

 

[Burunduk]

That note shouldn't be under that paragraph. Someone got mixed up between methods to smooth the surface and ways to smooth transitions between tolerance zones (why anyone would need to do the latter when not under the same confusion is a separate question).