abishek20
Mechanical
- Jul 8, 2010
- 4
Hi all,
I need to analyze tolerance for fit of two parts. I need to do this type of analysis with two sets of features:
FEATURE 1
One part has 3 pegs (120deg apart) and the other has holes. How do I calculate X directional shift of these two parts?
Here is what I did, let me know if this is correct:
Gap 1 = (Hole1-Peg1)/2
Gap 2 =....
Gap 3 =....
Xtol= min(gap1,gap2,gap3)
I did this because, the part can shift horiztonally while limited by the minimum allowable gap. But I dont feel this is the right way to do it.
Reason being, there is no consideration for the horiztonal shift occuring from the rotation of one part within the other.
No consideration for the combination of rotational and linear components of shift.
FEATURE 2
This is slightly more complicated. The features that engage with each other are still 3, and are at 120deg. However they are not pegs and holes.
They are trenches and pillars with a taper on each other. Here is am concerned about the following:
1. How the tolerance on the 120deg angle affects the fit along the axis.
2. How the individual rotation of these features affect the lateral shift.
3. How the individual rotation of these features affect the fit along the axis.
4. And lastly how the normal of these two parts end up (or the angle between these two parts).
If the second set of questions are more complicated, atleast any attempts at answering the first portion of my post would still be a lot of help.
Thanks in advance and sorry for the long post.
I need to analyze tolerance for fit of two parts. I need to do this type of analysis with two sets of features:
FEATURE 1
One part has 3 pegs (120deg apart) and the other has holes. How do I calculate X directional shift of these two parts?
Here is what I did, let me know if this is correct:
Gap 1 = (Hole1-Peg1)/2
Gap 2 =....
Gap 3 =....
Xtol= min(gap1,gap2,gap3)
I did this because, the part can shift horiztonally while limited by the minimum allowable gap. But I dont feel this is the right way to do it.
Reason being, there is no consideration for the horiztonal shift occuring from the rotation of one part within the other.
No consideration for the combination of rotational and linear components of shift.
FEATURE 2
This is slightly more complicated. The features that engage with each other are still 3, and are at 120deg. However they are not pegs and holes.
They are trenches and pillars with a taper on each other. Here is am concerned about the following:
1. How the tolerance on the 120deg angle affects the fit along the axis.
2. How the individual rotation of these features affect the lateral shift.
3. How the individual rotation of these features affect the fit along the axis.
4. And lastly how the normal of these two parts end up (or the angle between these two parts).
If the second set of questions are more complicated, atleast any attempts at answering the first portion of my post would still be a lot of help.
Thanks in advance and sorry for the long post.
