Blinds feeder for 24 mm embossed tape

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Lance Endres

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May 31, 2021, 11:38:40 AM5/31/21
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I really like the arrayed nature of the blinds feeder (thanks, Mark!).  The ones I made for 8 mm paper tapes worked perfectly, but I ran into some trouble when trying to use a 24 mm embossed tape.

The first issue was that was the fiducials were set at the bottom of the feeder while my focal plane for the camera is set at the top.  With the shallow depth of focus for my camera, this left the fiducials out of focus and they could not be recognized.  I wasn't able to locate a setting in the OpenSCAD files to move it to the top.  And not being familiar with OpenSCAD I haven't yet been able to figure out where to change it.  Or, alternatively, is there some other way to set up these deep pocket feeders that works?  I can't move the top of the feeder up, there is barely enough clearance to lift the capacitor out of the pocket, as is.
Focal Plane Issue.png

I also tried to hack the system.  I thought I might be able to create my own version and just take advantage of the arrayed nature of the blinds feeders.

New Feeder Design - Cropped.jpg

I wasn't able to get this to work for me either.  I am not able to pick the part at its center.  For the setup, I have the fiducial aligned with what I thought should be the first hole on the tape (the first one after the cut):
Alignment.png
But OpenPnP thinks the center of the part should be 4 mm further along the tape (to the right in the picture) than it actually is.  The location of the pick point is here:
First Pick Position.png
If you do another feed and pick, the next part is off by the exact same amount.  I cannot locate a setting in the feeder setup controls that changes this.  I don't understand what "Pocket Size" controls, but it doesn't seem to affect this issue.  Am I missing some setting?  Or does OpenPnP assume there is one more hole on the tape and that should be the first one?  I could move the start point of the tape back 4 mm, but it doesn't seem like this should be the intended design.  The tape set up is:
Tape Settings.png

Thanks,
Lance

ma...@makr.zone

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May 31, 2021, 12:46:09 PM5/31/21
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Hi Lance

Wow! These caps are monsters!

To be honest, I never even thought about such tall parts. Your approach to sink the part beneath the table is certainly the right thing to do.

> I wasn't able to get this to work for me either.  I am not able to pick the part at its center. 

My first rather wild guess is that you did not choose the right cover type.


The cover type affects how the parts are assumed to be located: with the BlindsCover, they only occupy one half of the pitch and they are half shifted, away from the starting edge. You need PushCover or NoCover.

> For the setup, I have the fiducial aligned with what I thought should be the first hole on the tape (the first one after the cut)

Yes, if I remember correctly, they should be in alignment.

> I don't understand what "Pocket Size" controls

It is the pocket size across the tape. It only affects where the part numbers are drawn.

There are tooltips on most field labels. An as further guide, the GUI is arranged in two columns, one per (local) coordinate axis of the feeder, i.e. along the tape vs. across the tape:

Note: I'm not a native English speaker, so if some of these or other terms are wrong in this technical context or if there is simply a better word available, please tell me!

> I wasn't able to locate a setting in the OpenSCAD files to move it to the top.  And not being familiar with OpenSCAD I haven't yet been able to figure out where to change it. 

I'll keep this valid use case in mind and the next time I lay hands on the BlindsFeeder I will give it an option to "sink it" beneath the table.  Perhaps with an option for flanges for suspended mounting.

> I really like the arrayed nature of the blinds feeder (thanks, Mark!).

Thank you for the kind words ;-)

_Mark
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Lance A. Endres

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May 31, 2021, 1:16:38 PM5/31/21
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>  My first rather wild guess is that you did not choose the right cover type.  The cover type affects how the parts are assumed to be located: with the BlindsCover, they only occupy one half of the pitch and they are half shifted, away from the starting edge. You need PushCover or NoCover.

Ah, I was not aware this affected anything other than the cover.  Good to know!  I did have it set to NoCover (as I did not have a cover).  Knowing this affected the starting point, I tried BlindsCover and that works perfectly.

I'll post my files as a (partial) stop-gap measure until the OpenSCAD files are updated.  In case anyone else has some big fat juicy capacitors to place. :-)   

Thanks for the help!
-Lance


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ma...@makr.zone

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May 31, 2021, 1:25:00 PM5/31/21
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> I tried BlindsCover and that works perfectly.

That's unexpected. 🤔

Lance Endres

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Jun 4, 2021, 12:32:03 PM6/4/21
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I've attached my files of a temporary work-around.  The attached zip package includes:
Solidworks source files
STLs (that worked for my printer)
Drawing PDFs (for reproducing, if required)

If you need help with something, let me know!
Feeder Array.png
Strip Feeder 24 mm.zip
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