How to chart hole location? Stamping parts with 4 holes each

[roland_lu]

We have a pair of stamping parts with 4 holes each. The drawing calls out that the hole locations are critical. We use a digital probe that can read hole location in x and y direction(y perpendicular to x) to measure the hole location.

I hope somebodies with similar experience can shed some light on how I shall structure the control charts so the operators on the floor can easily and quickly chart the readings?

Thanks for the help!

 

[Ederie - 2007]

Re: How to chart hole location?

Is there a geometric tolerancing call-out for the hole locations,
or do they have standard +/- tolerancing ?
Ed

 

[roland_lu]

Re: How to chart hole location?

it is sort of standard GD&T call-out. I have difficulty use this keyboard to type in the symbols.

basically, like this: Dia. 1.0 MMC [A, B(MMC), C(MMC)]

 

[roland_lu]

Re: How to chart hole location?

the simpliest way I think is to chart x and y separately. However, some information has got lost.

I am wondering if someone in the cove have met the similar situcation before.

 

[Ederie - 2007]

Re: How to chart hole location?

So use the deviation from nominal for the X & Y,
X(squared) + y(squared) = ______ (take the square root) (times 2)
that will give you the number you need. Hopefully it will under 1.0.

You probably don't want the people on the floor using the maxium material call out, tends to complicate things.

Ed

 

[Stijloor]

Re: How to chart hole location?

it is sort of standard GD&T call-out. I have difficulty use this keyboard to type in the symbols.

basically, like this: Dia. 1.0 MMC [A, B(MMC), C(MMC)]

Hi Roland,

I think, I have an idea what this GD&T callout looks like, but is it possible to scan (a part of this) drawing and attach it to your post?

- Does the callout apply to a four-hole pattern?
- Or, are the holes controlled independently?
- The datums and basic dimensions would be of help too.

It is very difficult to help you with just a description of the callout.

 

[Stijloor]

Re: How to chart hole location?

So use the deviation from nominal for the X & Y,
X(squared) + y(squared) = ______ (take the square root) (times 2)
that will give you the number you need. Hopefully it will under 1.0.

You probably don't want the people on the floor using the maxium material call out, tends to complicate things.

Ed

By all means, allow the use if the MMC principle.

Not allowing the use of the MMC principle would make the part unnecessarily expensive.

 

[roland_lu]

Re: How to chart hole location?

So use the deviation from nominal for the X & Y,
X(squared) + y(squared) = ______ (take the square root) (times 2)
that will give you the number you need. Hopefully it will under 1.0.

You probably don't want the people on the floor using the maxium material call out, tends to complicate things.

Ed

If I do that, I will have some misleading information. For instance, the difference between two same readings 0.3 and 0.3 may be 0.6 or 0 or other number between them.

Do you know what I mean?

 

[roland_lu]

Re: How to chart hole location?

to make live easier, I am going for X-MR chart:

X=(x^2+y^2)^1/2
MR=((dx)^2+(dy)^2)^1/2

dx, dy stand for MR-x and MR-y

But is it to much the calculation for the operators? any suggestions?

Thank you for the help!

 

[Claes Gefvenberg]

Re: How to chart hole location?

Not allowing the use of the MMC principle would make the part unnecessarily expensive.

Exactly. First of all, it would mean throwing tolerance away without reason, but even more important is the real beauty of MMC: That it allows you to use a function gauge. I think the operators would like that?

If I do that, I will have some misleading information. For instance, the difference between two same readings 0.3 and 0.3 may be 0.6 or 0 or other number between them.

Not at all, you can do it graphically: All you have to do is to plot the deviation from the nominal positions in x and Y axis into a coordinate system. From then on I am uncertain as we need to see the drawing, but the MMC may provide you with even more tolerance width to play with.

We really need to see the drawing.

/Claes