One-Sided Critical/Inspection Dimension Annotation

[TK-421]

Current State: We have a tightened tolerance on the high & low side of a dimension and we do a finished good inspection on both the high & low end of that dimension (with Go/No-Go gauges). See screenshot.

Desired State: Remove the tightened tolerance for the high end of that 9.64mm dimension and also denote that only the low end of the dimension needs to be inspected.

We use Solidworks and I can't find a format where I can denote only the low end as a critical dimension for inspection other than using the "MIN" notation, which isn't ideal as we want the high-end to revert to the block/sheet tolerance. From what I've read on these forums, the inspection "oval" is not part of the ASME Y14 standard (I looked in the standard and can't find it either). Do I just list both the high and low tolerances with the dimension in an oval and add a NOTE that only the low needs to be inspected? Is there a better way to reflect this? Thanks for any constructive thoughts/tips!

 

[r6155]

You can write "9.64 min."

Regards

 

[TK-421]

You can write "9.64 min."

Regards

Hi @r6155 — Thanks for the response! The issue is that we don't want to leave the high end of the tolerance unlimited. My understanding is that by using the "MIN" notation, there is no limit on the high end of the dimension. Is this correct? We would like to still keep the block tolerance of +0.38mm on that high end of the dimension.

 

[3DDave]

Previous discussion on the oval: https://www.eng-tips.com/threads/inspection-dimension-solidworks-drawings.290024/

I would give a try to using limit dimensions and then putting an oval around just the one, though I think it still requires a note that this is a one-sided limit and that the value itself is the only acceptable one.

 

[drawoh]

TK-421,

Are you preparing a drawing or working out an inspection process?

It sounds like the original drawing has been correctly presented. Perhaps you need an inspection tool that verifies the minimum dimension.

 

[TK-421]

TK-421,

Are you preparing a drawing or working out an inspection process?

It sounds like the original drawing has been correctly presented. Perhaps you need an inspection tool that verifies the minimum dimension.

It's a little bit of both. We're modifying the inspection procedure to only check the minimum dimension (we use a GO gauge to check low end of ID), but as such we don't want to leave the maximum dimension unlimited (i.e. with only a MIN annotation). It sounds like the option to update the drawing to show Limit definitions for the dimension with only the low end in the oval might be the best way to go. The only down side I see for this approach is that you're not providing the nominal target for the dimension, but we might be able to live with that compromise.

 

[drawoh]

.... The only down side I see for this approach is that you're not providing the nominal target for the dimension, but we might be able to live with that compromise.

It sounds like you are inspecting for the minimum value, and that you want to be below the maximum somehow. Should you care about the nominal value?

 

[TK-421]

Anyone have any idea how to "oval" just the Low end of the limit dimension? The built in Solidworks function will only oval both the high and low limits. Do I have to manually create a sketch object around that dimension?

 

[Garland23]

TK-421, what is the meaning that you intend to convey with the oval? I've often seen it used as a critical characteristic marker, meaning that it has to be inspected and tracked using statistics.
But if that's the intent, then it doesn't make sense to have an oval around a single limit. The statistical tracking is done on the tolerance, and tolerance is defined as the total amount that a dimension is permitted to vary.

 

[pmarc]

Anyone have any idea how to "oval" just the Low end of the limit dimension? The built in Solidworks function will only oval both the high and low limits. Do I have to manually create a sketch object around that dimension?

Simply apply two separate dimensions for the feature:
1. 9.64 MIN within the "oval".
2. 10.02 MAX with "oval" omitted.

I agree, though, that a note would probably be required anyway to explain the meaning of the "oval".