Strip clipping modeling

3D Design Surface Modeling
1

Hello

I try to model the path that a flexible strip would take that would fit a multi-sided piece. The purpose of this clipping is to orient the exit of the strip at 90° from its departure in a small footprint.

 

On the version 5 attachment, we have a folder called "Base shape" which is the raw form of my part and it is on the sides of the 3D1 sketch that I play to achieve the desired result (90° clipping).

We then have the sketch "Tape start " which models the start of the tape.

The folders named "2nd and 3rd detour" are composed in different steps that I carried out to find the clipping of the tape. There may have been a simpler way for these 2 folders using the "Sketched Fold" tool but this tool is not very stable on my 2013 version of SolidWorks.

There is also the "Tape output" sketch which allows you to check that my tape ends in the desired direction which is 90°.

In addition, if we measure the 2 strands of my strip via the "Strand lengths" sketch, we see that the 2 outer strands of my strip have the same length so that the clipping is correct.

In order to understand the point of building the strip path, you can try to change the angle from 40° to 42° of the 3D1 sketch and you will see that the 2 strands will no longer be the same length and therefore the angle is no longer 90°.

As you will have understood, this version of the part works but unfortunately, the foundry fillets are not modeled and the routing is therefore no longer done between 2 faces (edge). In addition, on the new version 8 of the coin, the start of the tape is no longer on the flat side but through another small detour that makes the tape arrive askew. Exhibit 8 illustrates this:

We still have the "Basic Shape" folder and after this folder we find sketch3D5, which represents the true start of the tape. The strip first passes through a detour Ø10 and it is tangent to this Ø and at the end of the detour. These different tangency constraints are found in the sketch for the bottom and top strands. I then draw a spline on the surface on the fillet to try to determine how the strip arrives on this fillet. And that's the problem because this spline is not exact and its precision is important to know the deviation of the band. Indeed, I use this spline to find planes 29 and 30 and then the bisector. In addition, we can see that the spline on the surface is not good because once we pass a boundary surface, the new surface created enters the surface of the detour.

So I don't know how to model this spline so that I always have a tangency of the band with respect to the Ø10 and the detour fillet. For example, if we cut along the plane33, we can see very clearly that the boundary surface is not tangent to the detour fillet.  Even if the spline is approximate, we can see that the projected curves are absolutely not parallel ("Check" sketch), which means that I will have to modify the shape of my detour to make them parallel and therefore have a correct clipping.

 

Sorry to have been long in my explanations but I think it was better to pose my problem well in order to understand the problem.

 

If anyone has a solution and/or a better method, I'm all for it.

 

Thank you.

2

Hello

Forgot your attachment!

1 Like
3

has


p-006206_5.sldprt
4

I can't fit them into the initial post so I do it like this...


p-006206_8.sldprt
5

Hello

Your subject seems complicated, I don't know if I understood correctly. So to sum up, your purple surface isn't tangent to a ray that you've projected a segment on at an angle? Would you like the segment that marks the end of your twisted surface to be parallel to the edge of the top surface  ? I have everything right?

At first glance it looks complex, for the tangent surface I would say cut the purple surface into several sections (make a skeleton in 3D sketch if possible).

6

Could you use pictures to illustrate your question please?

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Here's a picture of what I wish I had.  I know the start of my gang, it goes through a 1st detour Ø10 and then a 2nd detour Ø10. The multi-sided detour allows the strip to be oriented so that it passes underneath.

I want to model what happens on the 3rd and 4th detour in order to know how the tape is returned.

 

In the case of index piece 5, it's pretty simple to determine because we have sharp edges as a detour and the strip comes up on a flat surface. It is therefore easy to determine how the strip arrives and how it will be cut by creating the bisector etc...

But on index 8 (real case), the belt actually arrives in torsion and I need to know how the belt comes tangent on the 1st leave... In my 3D sketch "Tape Start", I drew the extreme fibers by making them tangent to the fillet and putting the points of the lines coinciding with this fillet. However, even if you know these 2 ends, you can see that when smoothing, the strip does not follow the detour...

I have already gone through the skeleton step by creating a dozen shots on the height of the strip and the result of the boundary surface was correct. However, SolidWorks doesn't like this and with each reconstruction, it makes me blow the spline that goes through the points of all the lines tangent to the fillet. 

 

I hope I have been clearer.

 

 


5.jpg
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has


8.jpg
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9

Ok, I understand better. In fact I think that in reality this strip cannot be entirely tangent to a uniform radius depending on your angles of reference, you would have to use a radius of variable size . Why model the gearbox and then the tape? It would be easier to create your subwoofer according to the orientation of your tape (turn the problem around actually).

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10

Something like that suits you

it's done via sketched folds

It's up to you to adjust the angles and radii of the folds and the sides 

But the principle works

unfold it

see attached file SW 2012

@+ ;-)


piece_jfrund_tolerie_deplie_plis_esquisse.sldprt
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11

With the sketched crease tool, I can indeed quickly create my clipping, but only for flat surfaces. So, for my gang arrival where the gang is torsoned, it doesn't work.

Being on it for a little while, I think I'm going to modify my design and bring in my tape so as to avoid this twisting. In fact, it will come back to the solution I described in index 5. I just have to include my holidays in addition.

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I don't understand well to solve your problem 

I don't have that the first 2 folds that are not created via the sketched folds tool

and it's simple 90° folds the other angles are created via the sketched folds

to  allow this strip to create a quarter turn and reverse the faces so turn this said strip over

and that this said band is always in contact with its supports or returns from training

you have angles of return to respect 

so take a good look at my part, it's in teloading and unfolding it

The radii and angles are to be optimized for your needs

via the sketched folds you are sure not to twist or distort this said strip

Do you have to work on it a little ;-)

@+ ;-)

 

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13

Indeed, the angle of the band's arrival in the fillet generates a twist. Why not use conical shapes for the return (hence the use of a variable radius fillet)?

Edit: in fact the strip is already twisted before reaching the fillet, so there will necessarily be a larger radius of curvature on one side compared to the other.

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14

you say

So, for my gang arrival where the gang is torsoned, it doesn't work.

If it works very well, the proof here ;-)

Do you take the option position of the folds as you should the 4th tab

otherwise it doesn't work

and you can set the radius to default

or you manage the department yourself

In this case, the Use default radius checkbox should be unchecked

@+ ;-)

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I agree with your remarks.

So I preferred to modify the arrival of my belt so as not to be dependent on the twisting of the belt which creates a different radius of curvature at each end as specified by "a.leblanc". Without modifying my arrival, I can't actually go through a sketched fold and the variable radius will give me a result that I won't be able to manage easily.

I'm attaching the part being modified for information purposes (don't pay attention to the tree structure, it's a mess...)

Thank you for your help.


p-006206_11.sldprt
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A screenshot is preferable, we don't all have the same version or the same log

and it can help everyone

Noting the answers with a thumbs-up indicates relevance in solving the problem

Putting a resolve on an answer gives the solution to the problem

It also gives points to the poster of the answers and it's nice

which de+ is allowed via these points to earn rewards and believe me you need a maximum to get the slightest gift

See Rewards tab in the black bar

@+

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Hello

Please see attached.


selon_moi.docx
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Here is the solution I have modeled. I used the sketched fold tool and I mainly modified the arrival of my strip so as not to have different radii of curvature between the top and bottom of the strip:

 

Thank you for your help!

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Oh yes, in fact your last piece is the trajectory of your tape, I thought it was the box, so the tape is located on the outside, which explains the orientation of the cone in relation to the trajectory.

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There's my detour piece in grey surface and the stripe in red. For the moment, it's all in the same room, it allows me to have the strip that evolves instantly according to the shape I give to my detour piece.