Resultant condition

[dtmbiz]

"The virtual condition of an external feature
is a constant value equal to its maximum
material condition size PLUS its applicable
tolerance of location.

The resultant condition of an external feature
is a variable value equal to its actual
mating envelope size MINUS its applicable
tolerance of location."

Considering an external cylindrical feature with a diameter of 10.1 mm to 10.5 mm with a diametrical tolerance zone of 0.1 at MMC; at the LMC the cylinder is dia 10.5 with a positional tolerance of 0.5. The resultant conditon is diameter 10 mm.

What practical application is there for the resultant condition of dia 10, considering it is smaller than the smallest cylinder diameter dia 10.1 ?

 

[axym]

dtmbiz,

In your example, the resultant condition would be 9.6. It's the LMC size (10.1) minus the applicable geometric tolerance (0.1 + 0.4 bonus = 0.5). The practical meaning of resultant condition is the zone in which there is guaranteed to be material.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[Belanger]

Evan nailed it -- but let me throw in this tidbit from the new standard.

The 2009 standard now thinks of RC as a constant value. In the 1994 standard RC was a variable (which was confusing because virtual condition was always thought of as a constant value).

So for the OP's question, we would formerly have said that 9.6 is the "worst-case resultant condition" but now we can just say that 9.6 is the "resultant condition."



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

 

[dtmbiz]

The example given was taken directly from the 94 standard; page 30 fig 2-7, right hand column. I did use a different diameter size.

There is a chart which goes thru some actual size values with the FCF calling out MMC. The chart starts with the MMC value and ends with "LMC", thus my useage of the term LMC in my example. This is not to be confused with the FCF using LMC. Confusing eh?

Isnt the fact that the cylinder's min size is dia 10.1 mm the garuanteed min material?

Its been awhile since I have been on the site and was wondering if you were still on here axym. Appreciate your comment.

 

[axym]

dtmbiz,

Using Y14.5-2009 terminology, the 10.1 is the smallest size that the "unrelated actual mating envelope" could be and the 9.6 is the smallest size that the "related minimum material envelope" could be. JP, does that sound correct? I don't have the standard in front of me.

In geometry terminology, the 10.1 is the smallest size that the "minimum circumscribed cylinder" could be and the 9.6 is the smallest size that the "orientation and location constrained maximum inscribed cylinder" could be.

If the feature was a hole and/or was referenced at LMC, then some of the terms would be switched in some way. ;^)

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca