topic Re: ROTATE command in AutoCAD Forum

ROTATE command

Anonymous — Tue, 14 Jun 2016 22:39:10 GMT

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

Re: ROTATE command

john.vellek — Tue, 14 Jun 2016 22:44:07 GMT

HI avishekaiyar,

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

Re: ROTATE command

Anonymous — Tue, 14 Jun 2016 23:08:28 GMT

John,

Attached is a dwg file.

Thanks a lot for the help.

avi

Re: ROTATE command

Anonymous — Tue, 14 Jun 2016 23:39:23 GMT

@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

Sounds like something that Inventor would be well suited for.

Re: ROTATE command

SEANT61 — Wed, 15 Jun 2016 07:22:54 GMT

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

Re: ROTATE command

Kent1Cooper — Wed, 15 Jun 2016 11:57:58 GMT

@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.

....

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:

Re: ROTATE command

JDMather — Wed, 15 Jun 2016 12:01:06 GMT

Are you a student?

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

Re: ROTATE command

john.vellek — Wed, 15 Jun 2016 14:29:26 GMT

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?

Re: ROTATE command

Anonymous — Wed, 15 Jun 2016 14:37:22 GMT

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

Re: ROTATE command

Anonymous — Wed, 15 Jun 2016 14:42:41 GMT

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

Re: ROTATE command

john.vellek — Wed, 15 Jun 2016 14:48:36 GMT

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.

Re: ROTATE command

JDMather — Wed, 15 Jun 2016 16:03:07 GMT

@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.

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.

Re: ROTATE command

Anonymous — Wed, 15 Jun 2016 20:02:42 GMT

Joh

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

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

But let me try.

Thx.

Avi

Re: ROTATE command

Anonymous — Wed, 15 Jun 2016 20:03:22 GMT

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

Let me try that out.

Thx.

Avi

Re: ROTATE command

SEANT61 — Wed, 15 Jun 2016 21:18:32 GMT

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

Good point.

Re: ROTATE command

john.vellek — Thu, 16 Jun 2016 15:47:17 GMT

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.

Re: ROTATE command

Anonymous — Thu, 16 Jun 2016 18:31:18 GMT

@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.

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

Re: ROTATE command

Kent1Cooper — Thu, 16 Jun 2016 19:02:49 GMT

@Anonymous wrote:

@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.

....

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

Re: ROTATE command

Anonymous — Thu, 16 Jun 2016 19:52:18 GMT

aah.....I just saw that.

Re: ROTATE command

Anonymous — Mon, 20 Jun 2016 14:32:50 GMT

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