export to centroids, how to set it to a specific point in the component?

[Lighting01]

I'm exporting a component that must looks likes:

PAD1    *      PAD2                                           PAD3

*=Center in centroidfile

But I get: 

PAD1           PAD2         *                                 PAD3

 *=Center in centroidfile    

  
How do I make my component to get the * to center in the export?

[Hossein128]

Hello,

The part cenrtroid uses the pin locations to find the footprint center, I believe Ultiboard tries to find the center point of the pin locations. Have a look at the attached example, there are only two pins and when you export the part centroid, the part center in between the two pins.

I hope that it will be usefull.

Regards,

[Lighting01]

But what to do when the center (between 2 pins) isn't the same as the pickup coordinates of the part?

Or if you have a component with three pads like my first example?

[Hossein128]

Hello,

Would you like to send me your code that I can work on it? It would be helpful. But you can check the link below to see how you can work with centroid file options.

http://zone.ni.com/devzone/cda/tut/p/id/3973

Hear from you.

Regards,

[stressed_user]

Hi,

The center pont of a part can be changed by editing it (only possible if the part is in the user database)

the in footprint edit mode, choose the 'Design tab / the select 'Set reference point' and the reference point will be attached to your cursor.

Then just place it where you need it...

succes!

stressed user

[Lighting01]

@ stressed user, you're right, but this doesn't work for the centroid file.

@ Hossein128, you received an example by email.

The link you provided doesn't have anything about export to centroid.

[stressed_user]

Lighting01,

Indeed, I have made myself a test design, with two physically identical parts, but I gave one an 2.54 mm offset in the reference.

When I place bot parts exactly on top of each other, they have a different location on the PCB.

In the centroids file however, they have the exact same location...

I have no idea (yet) how to change the centroids location....

but I found this on the screaming circuits website:

http://screamingcircuits.typepad.com/files/understanding-the-centroid-file-r2-1.pdf

In fact the centroids position should be the exact center of the part, and from a manufacturing point of view that is obvious.

You want the pick and place nozzle to take the part in its physical center.

Using the wizard in ultiboard automatically sets that to the center, (for this it's important to know the whole part, and enter its size correctly, not just look at the copper footprint...)

I wonder if there's a way to move this centroids position without making the part over again...

I also tried the following:

in the footprint edit mode, move all silk and all copper etc... no change in centroids position...

chaneg the shape of the silk: no change...

Maybe some of the NI people can help us out there...

best regards

stressed user...

[Lighting01]

And with some parts like a led (SMT) you want to pick it up on the lens.

There are leds with the lens in the side of the part.

---------------------------------

-                          A  -

-                              -

-     Lens                  -

-                              -

-                          C  -

--------------------------------

[stressed_user]

they're called rebel leds :-)....

I believe Lumiled (Philips) advises to pick them on the flat surface, not on the lens... that's in one of their application briefs...

stressed user