Hi everyone,
I have existing parts in which there are slotted holes, I would like to insert screws via stress references, how to set the stress references for a slotted hole? with a tangency? But how do you center it?
Thank you
Hello
You can put plane planes in the oblong, and then put constraints between the planes of the oblong and those of the screws.
Kind regards.
Fred
Hello Maximus
You ask more or less the same question as your previous position, where you almost changed your definition along the way.
The solution I proposed to you (if we don't stay strictly on the constraint reference) in the previous post remains valid in my opinion, but it doesn't seem to suit you.
I guess you tested it! If that doesn't work, surely you could tell us why. It would at least benefit the forum community.
Kind regards
1 Like
Hello fred :-)
What you propose is valid on the only condition that we stay centered in the oblong (so without play in the direction of the length).
If you want to have the game (it's the vocation of an oblong) you need 3 constraints, hence the proposal I made previously in the other post of maximus.
If maximus renounces the longitudinal clearance, then two constraints are indeed enough because you then reduce the problem to the equivalent of a bore and the cylindrical screw (Coaxial + (face under head and plating on sheet metal). Except that the constraints would be on two levels.
This means that we would be more concerned about the fact that it is oblong if we give up the CQFD longitudinal positioning game. ;-)
Kind regards
1 Like
Hello ZOZO,
So I suspected that I was going to be told, it's not the same question, in my other post I ask how to choose this or that stress reference when inserting a part in its assembly (either to insert it in a slotted hole or in a smooth hole).
In this post it's to ask what constraint reference to use to insert a screw in an oblong hole (so as not to rot the other one and find it easier for the one who will search, I also answered for the tangency in an oblong)
Hi Fred, thank you for your answer, the problem is that we have hundreds of these parts with oblongs, if we had to put a plane in each oblong it would be too long.
Hello
In a single step it seems difficult to me...
To center a screw in a slotted hole you can add a coincidence constraint between the axis of your screw and the middle axis of your slotted hole, provided of course that you have used the slotted hole function (straight groove) to make this one, so:
- Step 1: Display the axes.
- Step 2: Place the screw on the face near the slotted hole.
- Step 3: Install the coincidence between your screw and groove axes.
- Step 4: Your screw is centered in your groove.
It takes about 2 seconds to put a screw like that.
Kind regards
2 Likes
And if you don't want your screw to be centered then you put your screw next to it then you select an inside face of your slotted hole then the face of your screw head and you choose the groove stress:
and suddenly your screw wanders in your groove but only in it...
Kind regards
1 Like
Hi Roger, thanks for your tips, unfortunately, not all oblongs were made with the groove function, so they don't all have a centered axis.
Currently when I have my 50 screws to put in 50 smooth holes it's great, with the constraint references it goes very fast, but as soon as it's an oblong hole (and I can have 50 too) it takes me a crazy amount of time to center everything, I'm already more or less doing your technique (I put the screw nearby, so I already have a coincidence and I do a groove constraint afterwards), but it still takes a lot of time (I copy with the constraints it helps a little, but it's still much longer than directly laying the screw which could center itself in the oblong).
Yes, but in one step it seems really difficult to me...
And the trick of the middle axis of the slotted hole is only moderately good, but easier for visibility reasons, normally one should find a coincidence stress between the underside of the screw head and its bearing face on the workpiece having the slotted hole plus a groove stress between the slotted hole and the screw plus a concentricity between the screw and the thread which must be on the part behind the one with the slotted hole. The only stress that can be forgotten is that of the groove according to the stresses between the other parts, so theoretically, instead of taking the middle axis of the groove, we should take the axis of the thread for the stress of coincidence with the axis of the screw.
Kind regards
1 Like