Unknown Symbol...
Unknown Symbol...
(OP)
I've come across a symbol that I have not seen and cannot seem to find any info on... Particularly the "Circle U" followed by .0000? Any help to decipher would be great.
See attached pic of the frame.
Thanks
See attached pic of the frame.
Thanks





RE: Unknown Symbol...
<http://ask.yahoo.com/20011109.html>
RE: Unknown Symbol...
Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group
RE: Unknown Symbol...
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 08
ctopher's home (updated Aug 5, 2008)
ctopher's blog
SolidWorks Legion
RE: Unknown Symbol...
It refers to the distance from the surface a profile tolerance is offset. A distance of 0.000 means that the tolerance is bilateral.
This does away with having to draw a phantom line to denote which side a profile tolerance is applied to.
When the people fear their government, there is tyranny; when the government fears the people, there is liberty. - Thomas Jefferson
RE: Unknown Symbol...
V
RE: Unknown Symbol...
I'm not sure how they are going to handle it in the new Y14.5 release, but it probably won't change much.
By the way, "U" stands for "up", or outward from the surface.
When the people fear their government, there is tyranny; when the government fears the people, there is liberty. - Thomas Jefferson
RE: Unknown Symbol...
RE: Unknown Symbol...
Powerhound, GDTP T-0419
Production Supervisor
Inventor 2008
Mastercam X2
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: Unknown Symbol...
When the people fear their government, there is tyranny; when the government fears the people, there is liberty. - Thomas Jefferson
RE: Unknown Symbol...
The first time that I saw the Circle-U symbology was about 10 years ago in the GM Corporate Engineering Addendum. It has since been adopted into Y14.41, and is included in the draft of the upcoming Y14.5.
This symbol presumably came about because of the non-associative nature of the offset chain lines stipulated in Y14.5 to indicate unilateral and unequal bilateral zones. When the geometry was moved or changed, the offset curves didn't move and you could easily flip from a unilateral +ve to a unilateral -ve tolerance zone without ever noticing.
Unfortunately I don't think most cad packages are up to date on this symbology, so you may not even be able to use it yet. For those that can, and want to use the symbol, you can use the control and either directly below the FCF or in a note or corporate addendum invoke the Circle-U per ASME Y14.41-2003.
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: Unknown Symbol...
To clarify my thought pattern on this, I refer to "inward" as relative to the surface indicated, thus inward on the surface of a hole would make the hole bigger, because the direction is toward the material; same thing with "outward", which would make the hole smaller, being away from the material. Same intent, different symantics.
In my own defence, I did point out that the standard specifies the symbol for "only unilaterally and unequally disposed applications" (paraphrased directly from the standard).
I guess it's time to take a refresher course... on this and on Communication 101. ;)
When the people fear their government, there is tyranny; when the government fears the people, there is liberty. - Thomas Jefferson
RE: Unknown Symbol...
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: Unknown Symbol...
The definition given in Y14.41 actually says "outward". It makes no mention of adding mass or anything like that. Whether the feature is male or female makes no difference. I don't know what makes you think this. What's being controlled is the surface of the feature and inward of the surface means only one thing...into the part surface. Outward means away from the part surface. This is clearly illustrated in Y14.41-2003.
What you said about adding mass is not wrong but it complicates the issue when phrased like that. Maybe I'm just not that smart. ewh got it right with his simple illustration.
Powerhound, GDTP T-0419
Production Supervisor
Inventor 2008
Mastercam X2
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: Unknown Symbol...
Yes it does say outward from the surface. I use the convention "the portion following the circle-u is the portion that goes to the side that adds mass" because I typically get people trying to say it makes the feature smaller, or it makes the feature larger, depending on what kind of parts they're used to thinking of. "Outward" from a surface could be taken to mean radially outward (i.e. the circular feature gets larger) which makes a difference then whether it is a male or female part. Figure 10-18 in Y14.41 actually has an error as it shows the offset to the inside (correct) while showing the dimension lines to the outside. I use the mass analogy for teaching MMC & LMC also, so it's a natural mental continuation for students. Most people that I've taught have pick up the idea of adding mass quicker than understanding what outward "from the surface" means, and using a common concept helps to get the basic idea across efficiently. It's too easy sometimes to get into the rut of communicating things the easy way rather than the correct way.
Tks for the corrections. Like I said, it's been a long day.
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: Unknown Symbol...
1. Abbreviation of uracil
2. The symbol for uranium.
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 08
ctopher's home (updated Aug 5, 2008)
ctopher's blog
SolidWorks Legion
RE: Unknown Symbol...
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: Unknown Symbol...
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 08
ctopher's home (updated Aug 5, 2008)
ctopher's blog
SolidWorks Legion
RE: Unknown Symbol...
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: Unknown Symbol...
Powerhound, GDTP T-0419
Production Supervisor
Inventor 2008
Mastercam X2
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: Unknown Symbol...
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: Unknown Symbol...
Powerhound, GDTP T-0419
Production Supervisor
Inventor 2008
Mastercam X2
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II