sheet metal punch trouble - again

[frugal]

Hi All,

I know that there have been multiple posts about making a sheet metal punch with Extract iFeature, but I've been banging my head against this all day and can't find a solution.

Simple punch-outs I can do. I've also looked at a few step-by-step guides and I've managed to get a working revolved "dimple" punch to work. What I cannot do is get this swept louver to work:

I've been very careful to turn off the center point button when drawing sketches after creating the so-called "interface sketch".

I've also carefully deleted the auto-projected part centers.

In the attached file, if I move the EoF marker above the sweep, I can create the ide file - the punch knocks out a slot.

When I try to include the sweep in the iFeature, I get the "Sketch does not qualify as a punch placement sketch" error.

This is presumably because there is another conflicting center point in the one or both of two other sketches I created - but I cannot find it.

Any hints would be much appreciated.

Many thanks,

Thomas

[mdavis22569]

that's why I gave up and just downloaded the .ide from Cbliss    

http://cbliss.com/inventor/iFeatures/index.htm

[PaulMunford]

Yep. Downloadthe Charles Bliss version and take a look at how he built it.

[TheCADWhisperer]

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@frugal wrote:

I've also carefully deleted the auto-projected part centers.

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Are you sure about that?

[frugal]

Thanks - I had come across cbliss's page, but they none of them were quite what I wanted. Silly me for presuming that making my own would be a half hour job. I also redid the tutorial here to see if I could figure out what is going wrong. That one throws the same error when I try to extract the iFeature.

RANT: THIS REALLY SHOULD NOT BE THIS HARD.

I will take a closer look at cbliss's to see if I can adapt one.

Many thanks

[frugal]

Thanks for the reply.

That point is indeed projected, but

a) it is not a centre-point

b) the projection is made from the placement sketch - which, as far I had understood, is supposed to be allowed.

If you delete that point, there is no way to align the features defined in the new sketch to the placement sketch. .... which kind of defeats the point.

Thomas

[TheCADWhisperer]

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@frugal wrote:

....RANT: THIS REALLY SHOULD NOT BE THIS HARD.

I will take a closer look at cbliss's to see if I can adapt one.

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It is really easy once you know how.

Caution on the cbliss examples as they were created before Sheet Metal Punch tool existed in Inventor.

[frugal]

Ok, I took a closer look at one of cbliss's examples. The ide file no longer works in inventor 2017. Not too much of a surprise.

If you try to use the IDE file the error is that the "File has zero hole centers in the interface sketch."

So I opened the IPT file and added one to the first sketch after the face definition.

However, I still cannot get the iFeature extraction to work.

As with my original attempts - I can get the first or second extrusions to knock-out a hole - but as soon as I try to add the sweep, it fails.

[TheCADWhisperer]

Before I post example, is the design in your original post what you really really are after for your punch?

(punched opening, not closed dimple)

[TheCADWhisperer]

Well, I got tired of waiting for response.

Example attached.

[frugal]

Not sure why it took so long to receive the notification of your reply - sorry.

In answer - yes, what I drew is pretty much exactly what I am trying to accomplish.

Yours is REALLY CLOSE. The tests you did were on a face that was created on the XY plane.

I created a new sheet metal part with a face on the XZ plane and the punch fails.

If I redraw the same face on the XY plane it works.

I presume that this is some kind of dependency problem?

I haven't looked carefully at the ipt file yet - but HOW on earth did you get the iFeature to extract?

Many thanks

[TheCADWhisperer · Accepted solution]

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@frugal wrote:
...I created a new sheet metal part with a face on the XZ plane and the punch fails.

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@frugal

Oops, see revision attached.

After experimenting a bit more - I think I would make some changes so that invalid parameters could not be used - but I didn't know your precise design intent.

[frugal]

IT WORKS!   Thank you.

I am still baffled by this process however.

I opened your original ipt and managed, after quite a bit of fussing, to recreate the IDE.

I am going to take a closer look at the revision to see if I can spot the difference, but if you could explain, it would be greatly appreciated

Thanks again

[frugal]

That is a clear explanation of the process - which I have not come across anywhere else.

The dependencies are the killer here.

Many, many thanks.