ROTATE command

[Anonymous]

Hello,

I am looking for a very specific use of the ROTATE command. I am trying to simulate the alignemnt of a 200mm wafer using 2 pins. 

The idea is we cut 2 notches (a V notch at end of the wafer and an L notch at the opposite end). The wafer pivots about the pin that locks into the V notch and rotates until it hits the L notch. This results in a coarse alignment of the wafer. 

I am trying to understand how I can simulate the effects of notch imperfections. As an example, what would happen if the base of the L notch is 100 um lower than where it is supposed to be. In such a scenario, how can I use the ROTATE command (the base point would be the center of the pin that locks into the V notch) so that the base of the "new" L notch is still a tangent to the stop pin (the pin that hits against the L notch). 

See the attached PNG file that explains the problem statement. I wish to achieve this w/o having to calculate the rotation angle required. 

I was really hoping that I could snap to the tangent as I rotate, but that does not work.

Any advice would be much appreciated.

Thanks.

Avi

[john.vellek]

HI avishekaiyar,

This sounds tricky. Is it possible to attach a sample file so I can try to emulate what you are asking for?

[Anonymous]

John,

Attached is a dwg file. 

Thanks a lot for the help.

avi

[Anonymous]

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@Anonymous wrote:

Hello,

I am looking for a very specific use of the ROTATE command. I am trying to simulate the alignemnt of a 200mm wafer using 2 pins. 

The idea is we cut 2 notches (a V notch at end of the wafer and an L notch at the opposite end). The wafer pivots about the pin that locks into the V notch and rotates until it hits the L notch. This results in a coarse alignment of the wafer. 

I am trying to understand how I can simulate the effects of notch imperfections. As an example, what would happen if the base of the L notch is 100 um lower than where it is supposed to be. In such a scenario, how can I use the ROTATE command (the base point would be the center of the pin that locks into the V notch) so that the base of the "new" L notch is still a tangent to the stop pin (the pin that hits against the L notch). 

See the attached PNG file that explains the problem statement. I wish to achieve this w/o having to calculate the rotation angle required. 

I was really hoping that I could snap to the tangent as I rotate, but that does not work.

Any advice would be much appreciated.

Thanks.

Avi

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Sounds like something that Inventor would be well suited for.

[SEANT61]

You could use a circle as a constructional aid, then Rotate with the Reference option to align it to the two intersection points.

[Kent1Cooper]

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@SEANT61 wrote:

You could use a circle as a constructional aid, then Rotate with the Reference option to align it to the two intersection points.

....

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That works only if the "base" of the "L" is radial to the larger Circle.  Theirs is not.  An exaggerated example [blowup of the immediate area on the right:

[JDMather]

Are you a student?

If so, then I would download Autodesk Inventor for this and learn about Contact Sets, or better yet, Dynamic Simulation.

[john.vellek]

Hi Avi, I hope some of the suggestions in this thread help. I too, was going to suggest a construction circle to be used for a reference. This is what I have done for a long time but as you point out, it does have its limitations.

Is Inventor an option for you?

[Anonymous]

John/All,

Thanks so much for all the suggestions. I am going to try the circle option and see what I get. 

I am not a student, but if I show enough promise with Inventor I might be able to convince my company to purchase it.But I can try it out.

Thanks.

Avi

[Anonymous]

what I did as a quick and dirty alternative is to simply rotate the wafer in discrete and tiny steps until the L-notch "looks" tangential to the pin. 

Not the most elegant approach but gets me with 10s-100s nanometers of the errors I am trying to calculate, which might be ok for now. 

Thank you.

Avi

[john.vellek]

Hi Avi,

Along that thought, can you construct a tangential line and then measure the angle of rotation? If this works you could probably right a macro in Action Recorder to automate some of the steps for you.

Please hit the Accept as Solution button if my post fully solves your issue or answers your question.

[JDMather]

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@Anonymous wrote:

what I did as a quick and dirty alternative is to simply rotate the wafer in discrete and tiny steps until the L-notch "looks" tangential to the pin.  

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Actually, I don't think you need Inventor for this - I think it can be done correctly (not just trial and error) using the Geometry Constraints on the Parameters tab.

[Anonymous]

Joh

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Along that thought, can you construct a tangential line and then measure the angle of rotation? 

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@john.vellek wrote:

Hi Avi,

Along that thought, can you construct a tangential line and then measure the angle of rotation? If this works you could probably right a macro in Action Recorder to automate some of the steps for you.

Please hit the Accept as Solution button if my post fully solves your issue or answers your question.

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John,

That may not work since I wouldn't know what angle to draw the tangent line at. 

But let me try.

Thx.

Avi

[Anonymous]

I didn't know about that option. Thanks for pointing that out.

Let me try that out.

Thx.

Avi

[SEANT61]

"That works only if the "base" of the "L" is radial to the larger Circle."

Good point. 

[john.vellek]

HI @Anonymous,

I am checking back to see if my post or others helped you with your problem. Please add a post with your results so other Forum users can benefit.

Please hit the Accept as Solution button if a post or posts fully solved your issue or answered your question.

[Anonymous]

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@SEANT61 wrote:

You could use a circle as a constructional aid, then Rotate with the Reference option to align it to the two intersection points.

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Hi Sean,

I think this approach will work really well. 

Could you type out the sequence of steps? I really couldn't follow the steps as they were playing out in the video.

Really appreciate the help.

Thank you.

Avi

[Kent1Cooper]

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@Anonymous wrote:

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@SEANT61 wrote:

You could use a circle as a constructional aid, then Rotate with the Reference option to align it to the two intersection points.

.... 

I think this approach will work really well. 

....

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It's the approach I used to get the doesn't-work-exactly image in Post 6, so you may want to reconsider....

[Anonymous]

aah.....I just saw that. 

[Anonymous]

Folks,

Thanks a ton for all your suggestions. 

I think for the moment I am going to stick to my quick and dirty approach. 

I did get a demo on SolidWorks and there is a very elegant way to do exactly what I want (collision detection between parts). I might just go down that path long term.

Avi