Simultaneous Requirement, does it apply to single holes and patterns?

[fsincox]

I was discussing the simultaneous requirement with someone and looked again at the section on it and realized I was expecting it to be applied among patterns that essentially included a pattern of one hole. Can a single hole be a pattern or more importantly do identical frameworks keep the single hole clocked with other patterns on the part, what say you all??
Maybe this is what CH was getting at when he asked for a definition of a pattern in another thread?
Frank

 

[axym]

Frank,

I say yes. Identical frameworks keep the single hole clocked with other patterns on the part.

There isn't anything in Section 4.19 indicating that sim reqts only applies to patterns. It starts by saying that "a simultaneous requirement is where two or more geometric tolerances apply as a single pattern". So I don't think that there'e anything preventing a single hole from being included in a simultaneous requirement, regardless of what the definition of a pattern is.

The definition of a pattern would apply more to the application of composite FCF's.

This is for 2009 anyway - I don't have 1994 in front of me at the moment.

PS - Figure 4-40 shows two single slots aligned by simultaneous requirements.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[fsincox]

Evan,
Thank you for your input. In the 1982 standard it is stated in the section 5.3.6 "Multiple Patterns Of Features Located By Gasic Dimensions To Common Datums", It constantly refers to "patterns of features". I see now it looks like 1994 added "feature or patterns" to the discription of the "simultaneous requirement".
Good that should help me sell it.
Frank

 

[SeasonLee]

Y14.5M-1994 4.5.12 states:
Where two or more features or patterns of features are located by basic dimensions related to common datum features referenced in the same order of precedence and at the same material condition. …

Attached fig.4-8 from Y14.5-1994 is a good example on your question. Label A is a single hole while label B is a four holes pattern, but they have common datum referenced in the same order of precedence and at the same material condition, so both of them (label A and Label B) are considered as simultaneous requirement, and both of them will be built and inspected on the gage simultaneously since it is simply one way to verify a simultaneous requirement.

Season