Flatness per unit length

[Tunalover]

Folks-
A vendor has told me that the flatness of a specific area on a part is 0.001 inches/inch. How would I state this requirement using a feature control frame? I don't have Y14.5.
Thanks


Tunalover

 

[MechNorth]

Check out this tip from Tec-Ease:

http://tec-ease.com/gdt-tips-view.php?q=158

Jim Sykes, P.Eng, GDTP-S
Profile Services

http://www.profileservices.ca

TecEase, Inc.

http://www.tec-ease.com

 

[pmarc]

Jim,
Some questions to you:
What if required length of the area in direction of dim. 200 was 20 and not 50. How would you specify the requirement?
What if I wanted to define per unit area as 20 x full width of the part? How would you do it?

 

[Belanger]

To the OP -- you need an area, not a length. So you can't really say 0.001 inch per inch. It would be OK to say 0.001 inch per 1X1 area. But make sure that's what they want.

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

http://www.gdtseminars.com

 

[ctopher]

Some more tips:
Flatness GD/T

thread1103-254515

Forum

Measurement

Chris
SolidWorks 11
ctopher's home
SolidWorks Legion

 

[MechNorth]

pmarc,
Neither scenario is illustrated in the standard, but I would look at using the X/Y/Z (uppercase) labels, to show the layout; in the second scenario, I would use the width dimension value rather than "full width X 20".

Flat| 0.1 / 20[X] X 90[Y]

This is an extension of principles, of course; supported by flatness per unit area AND in '09 (integrated from Y14.41 '03), the use of the X,Y,Z vectors based on drawing views. Though I haven't seen anyone do this yet, I don't see any conflict with the standard.

Jim Sykes, P.Eng, GDTP-S
Profile Services

http://www.profileservices.ca

TecEase, Inc.

http://www.tec-ease.com