Flatness of a theoretical plane + Weird Parallelism

[Stbasser91]

Hi guys,

I have a constructed plane made from the two planes of a groove. The customer wants the flatness of that constructed plane.
But the constructed plane does not constit of the single points of the two planes. Is there a way to get that flatness?

The next issuse is about the parallelism. The part has six grooves on its outer diameter and a hole that is above one of the grooves. The datums are A (plane), B (outer diameter), and C (hole above the groove). The parallelism contains these three datums. And that is what irritates me. Two of the constructed planes are parallel to the C-datum. But the other four aren´t. So I don´t see a way to report the parallelism of all six constructed planes.

[JEFMAN]

1 : Construct a feature set with PL1.HIT[1..PL1.NUMHITS] and PL2.HIT[1..PL2.NUMHITS] then construct another plane and dimension the flatness.
2 : a parallelism with 3 datums ?????????? A location, ok, not a parallelism !

[Stbasser91]

1. When I do that I get a plane that is perpendicular and in the middle of the two planes.

2. Right?? Thats excatly what I thought. I´ll a few days, maybe someone knows something.

[AndersI]

Flatness of a constructed plane is zero, as flatnes is a physical property.

Combining the two planes as JEFMAN suggests assumes that the planes are directed the same way, located at the same height. The two sides of a groove are opposite, so this wouldnt work.

The only way I can think of is collecting *exactly* opposite points on the two planes, create midpoints, and create a plane BF from the midpoints. But what would the result *mean*??

Might be better with a CZ FORM dimension?

[JEFMAN]

I thought it was two planes separated by a groove

[AndersI]

Actually, it might be - the thought never occurred to me.

[Stbasser91]

@Andersl is right. I mean the Two planes of the groove. Not the planes seperatet by a groove. That´s what makes it so difficult. I know how to connect two seperate planes that are on the same level.

I am now in a conversation with the customer. He agreed to use a common zone. Can I apply that to two planes that are not on the same level?

[AndersI]

I am now in a conversation with the customer. He agreed to use a common zone. Can I apply that to two planes that are not on the same level?

You can create a set of the hits of the two planes to do a FORM dimension of the groove (like a WIDTH feature). You can't get a FLATNESS dimension.

As I said earlier:

The only way I can think of is collecting *exactly* opposite points on the two planes, create midpoints, and create a plane BF from the midpoints. But what would the result *mean*??

[NinjaBadger]

Hi guys,

I have a constructed plane made from the two planes of a groove. The customer wants the flatness of that constructed plane.
But the constructed plane does not constit of the single points of the two planes. Is there a way to get that flatness?

The next issuse is about the parallelism. The part has six grooves on its outer diameter and a hole that is above one of the grooves. The datums are A (plane), B (outer diameter), and C (hole above the groove). The parallelism contains these three datums. And that is what irritates me. Two of the constructed planes are parallel to the C-datum. But the other four aren´t. So I don´t see a way to report the parallelism of all six constructed planes.

Sounds like they really want angularity, not parallelism.

[Ego Murphy]

Hi guys,

I have a constructed plane made from the two planes of a groove. The customer wants the flatness of that constructed plane.
But the constructed plane does not constit of the single points of the two planes. Is there a way to get that flatness?
.

The customer doesn't know that they really want Profile of a set composed of both walls.

The next issuse is about the parallelism. The part has six grooves on its outer diameter and a hole that is above one of the grooves. The datums are A (plane), B (outer diameter), and C (hole above the groove). The parallelism contains these three datums. And that is what irritates me. Two of the constructed planes are parallel to the C-datum. But the other four aren´t. So I don´t see a way to report the parallelism of all six constructed planes.

As NinjaBadger posted, they don't know that they want Angularity.

Diplomatic but firm GD&T education of customers = required skill for CMM programming

[UseAsIs]

Sometimes customers will give you drawings that just don't make any sense. I know that isn't a particularly helpful comment, but it is something to consider to help put your mind at ease. Sometimes you just have to interpret what it is they actually want, measure it that way, and buy it off the best you can based on what is possible to measure.

[Ego Murphy]

... and buy it off the best you can based on what is possible to measure.

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