HOLE PATTERN POSITION CONTROL- FCF SUGGESTIONS

[Vimalmechs]

Hi all,

Please have a look on the PFA.
My Functional requirement is, I want to control the movement of hole pattern.” Pattern should be parallel to DATUM A or B or together, holes should shift together and hole pattern can move within .04 dia zone.

1) All the holes should be within .04 dia zone .
2) Hole pattern should move together. pattern rotation is not allowed more than .010 zone. Movement should be parallel to A DATUM or parallel to B DATUM or BOTH.

I have implemented FCF based on my requirement. Any one please highlight that any alternate options are available to achieve the same?

Vimal VV

 

[Vimalmechs]

hI, please refer this attachment instead of previous one.

 

[Belanger]

What you've shown does achieve the requirements stated. However, in most practical applications, it would be advisable to include the front or back face of the plate as a datum, and make in the primary datum.

Also, which GD&T standard are you using? (ISO or ASME)

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

 

[Vimalmechs]

My part is a sheet metal.Thickness is not a concern for me.Thats why i have avoided.
I am using ASME.

Vimal VV

 

[Belanger]

No, you need to include the face of the part as a primary datum. And actually, a thin part such as sheet metal needs such a datum even more! This is because it would be difficult to establish the primary plane from such a thin edge as your current datum A. Think about the stability, or wavering of the plate in and out of the picture as drawn now.

So re-write datum feature A as the back face, datum feature B as the bottom edge, and datum feature C as the left edge. Then the only changes to the composite feature control frame would be to add datum C to the upper portion, and add datum B to the lower portion.

If you have a copy of the ASME standard, the datum references would look much like the callout in Figure 7-39 of the 2009 edition, or Figure 5-20(e) of the 1994 standard.

You might also consider an MMC modifier after the tolerance values, but this depends on the function of the holes.

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

 

[Vimalmechs]

Thanks JPB.

 

[Vimalmechs]

Thanks JPB.