×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

"Simultaneous Requirement"?
2

"Simultaneous Requirement"?

"Simultaneous Requirement"?

(OP)
  I have a customer drawing with some holes controlled with compound true position callouts.  Under the true position block is "SIMULTANEOUS REQUIREMENT".  What does this mean?
  I understand that both parts of the compound true position are simultaneous requirements, but does this need to be spelled out separately, or is this just a redundancy?

RE: "Simultaneous Requirement"?

I have never seen this before. Seems redundant to me. Redundancy is very common.

Chris
Systems Analyst, I.S.
SolidWorks/PDMWorks 05
AutoCAD 06
ctopher's home site (updated 06-21-05)
FAQ559-1100
FAQ559-716

RE: "Simultaneous Requirement"?

(OP)
  Thanks, Chris.  That is what I am thinking, but wanted to be sure that I wasn't missing something.
  It sometimes seems that there are as many ways to interpret the standard as there are people using it.

RE: "Simultaneous Requirement"?

2
"Simutaneous Requirement" is understood in ASME Y14.5M-94 when there would be situation containing various positional tolerances referencing the same datums. This means that there is one (1) checking fixture for all the positional tolerances referencing the same datum in the same mode (MMC)rather than a separate fixture for each positonal tolerance.

I don't believe that many people know this so the Designer in this case stipulated it.

The standard also states that if the Designer required a separate requirement in one (1) positonal tolerances, then the Designer would state "SEPARATE REQ". The one (1) positional tolerance noted must be checked or confirmed separately while the other ones would be checked or confirmed simutaneously.

Hope this helps.

DD

RE: "Simultaneous Requirement"?

(OP)
Thanks again Dingy2!

I really appreciate your take on these questions.

RE: "Simultaneous Requirement"?

So, although it is obviously a "Simutaneous Requirement", it was listed as clarification for the company.

Chris
Systems Analyst, I.S.
SolidWorks/PDMWorks 05
AutoCAD 06
ctopher's home site (updated 06-21-05)
FAQ559-1100
FAQ559-716

RE: "Simultaneous Requirement"?

By Y14.5M multiple composite positional tolerance feature control frames (ptcf) by default create separate requirements even if the datums are in the same order.  If there are 'N' ptcfs then there are 'N' separate requirements.  For example, a four-hole pattern of .106 diameter holes controlled with a composite ptfcf utilizing A/B/C in the top line and A in the bottom line.  Next, consider if there were another pattern of, say, ten .250 diameter holes in the same part having its own ptfcf where A/B/C is also in the top line and A is in the bottom line.

By default, these two requirements are SEPARATE (the note SEPARATE is not needed) indicating that the two hole patterns are independant (and probably do not mate to the same part).  If the ptfcfs were not composite but instead possessed a single line then the requirements would be SIMULTANEOUS by default.

In the composite case, if you don't want the requirements to be separate, then the placement of the note SIMULTANEOUS under either ptfcf overrides the SEPARATE default and makes the requirements simultaneous.

Tunalover

RE: "Simultaneous Requirement"?

Tunalover:

Your notification the simultaneous requirements are defaulted in groups of composite feature control frames kind of threw me as bit. I check the Y14.5M - 94 standard 5.3.6.2 Page 93 and you are partially correct.

Simultaneous applications do apply to the top section of the composite feature control frames (PLTZF) but not the bottom or the (FRTZF). If you know of any other section which is more explicit to you thoughts, please let me know.

I learned something myself on this about the bottom sections of composite feature control frames and I have been training in this subject for 18 years.

DD

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources