Distance between centers and check dimension doubt in ZEISS INSPECT 2023

[[Lu...]]

Hi!

Could anyone tell me the workflow for getting the distance between centers of this?

I have constructed the 2 cylinders with GD&T> Dimension (independency principle)>Right click and fitting cylinder.

Now I was trying to get the distance by putting a point in the centerline and getting the distance, but I don't know which of all the tools to use. Or maybe could someone suggest me another way? 

Also, when creating the cylinder, the software opens a Check Dimension window in which it says a value, in this case 237.619mm, but when the label is created, it says nominal: 237.62 (the same as 237.619) and Actual 238.05 and 237.41, what are these  last 2? Which one would be the "real" dimmension?

Thanks!

 

[[Lu...]]

Hi Luis, 

on issue 1: There are many ways to do this, it depends a bit on the information you need. Here are 3 examples:
1) You could put another fitting plane on the top plane, and then build the intersection point (Construct -> Point -> Intersection Point) of the two axes with this top plane. You can then create a two-point distance.
2) You could create a 2-line distance with the two axes (Construct -> Distance -> 2-Line-Distance). This would be the shortest distance between these two axes.
3) You could define one axis as a datum and check the position of the other axis via GD&T Quick Creation. This would be the most precise way, whereby you should know the nominal distance of the two cylinders for the position deviation of one cylinder.

on issue 2: There is no "real" deviation, it depends very much on the particular element associated. If you are not using CAD (i.e. no nominal data), then the software itself must read out a nominal value against which it can compare the deviation. This nominal value is taken from the fitting element. By default, the dimension check (i.e. the actual data) is the so-called two-point size, in simple terms, the shortest and longest distance between two opposite points. If you would not inspect the cylinder using the independence principle (GD&T), but simply using I-Inspect -> Check -> Diameter, then only one dimension would be displayed (the diameter of the fitting element you created).

I hope that helps for now.

Lukas

 

Edited January 15

[[Lu...]]

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Hello Lukas, thanks for you answer.

i've been able to do the first 2 ways, in which I got different distances. When using between points constructed from intersection from line and plane, I get 177,66 mm and when using just the 2 axis of the cylinder, i get 177,31 mm.

I assume that the plane I created on the top is not that accurate becauase there are a lot of grey spaces and a little green spaces...

How could I do the third way? I really don't know how to do the datum axis nor the real center distance. This is a piece I'm trying to reconstruct.

 

How could I do the third one?

I'm trying to

[[Lu...]]

Hello Luis,

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the deviations between these two methods are completely normal and are due to various geometric deviations of the separate elements. This can be, for example, the tilted position of the cylinders, the perpendicularity of the plane to the separate cylinder axes, etc. ... Each separate method of determining this distance between the two cylinders will be slightly different. This is simply due to the deviations of the part.

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If you have constructed the upper plane as a fitting element, then the Gauss element is selected as the default for the association. This is an average element, which ensures that some areas are above the plane (grey) and some areas are below the plane (green). Basically, this has nothing to do with any "accuracy", but rather with the method of extracting this plane. You can click on your plane 1, then F4, and select a different "Method", e.g. Chebyshev best-fit and location "Outside". This would then be an outside plane that does not interfere with the material.

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The method works as follows:
1) GD&T Quick-Creation -> Create Datum System -> For Datum 1 choose Cylinder 1 -> Create

2) Choose Cylinder 2 -> GD&T Quick Creation -> Position -> For Datum System you choose your created "Datum system 1"

3) The software now calculates a "True Position" based on the actual elements. If you want to reconstruct the components, this value would be relevant for you.

Note however: None of the methods is absolutely correct for reconstructing the component, there will always be a uncertainty due to the geoemtric deviations of the component from which you want to reconstruct.

 

 

Edited January 16