Is there any way for 0816 Feeder to work with 0402 components?

[huynht...@gmail.com]

Hello.
I am using 0816 Feeder control board along with my Feeder. Everything is very fine for 4mm, 8mm, 12mm steps
However, at 2mm step it really doesn't work well, it's not accurate.
I saw Mark mention that ReferencePushPullFeeder can be adjusted to make Feeder 0816 work with 0402. I tried configuring it, but I can't add the Feeder open/close command.
Hope to get help from you!
Thank!

[PP.ca]

ReferencePushPull feeder has support for actuators, that's where you would select the one for your 0816 feeder.

Using the 2mm pitch with a servo motor might not work out that well because the servo needs to move at "half-angle" which does not always have the best value. One would need to figure out the exact half-angle so the part pocket is in the exact same position as for full-angle. It's quite a bit a fiddling and trial and error to determine that half-angle value, then store it for that feeder port and when you change the feeder re-adjust for the new one.

The most reliable way I have been able to make it work with 2mm pitch components was to set the part pitch at 2mm and the feeder pitch at 4mm.

This way, there is one actuation every 2 picks and the locations of the 2 exposed parts are nicely found by the vision calibration.

If you can't figure out the ReferencePushPullFeeder, try the BambooFeederAutoVision (test branch): the vision calibration is exactly the same and it's a bit more straight-forward about configuring the servo actuator since it doesn't have any head movements for the push-pull motions.

[mark maker]

> The most reliable way I have been able to make it work with 2mm pitch components was to set the part pitch at 2mm and the feeder pitch at 4mm.

Just to make it extra clear for anyone reading along: 

ReferencePushPullFeeder (and BambooFeeder in test branch) only support this option. They use sprocket hole vision and only supports integral multiples of the sprocket hole pitch.

> This way, there is one actuation every 2 picks

That's correct, it only actuates every second feed, and also only does calibration vision every second feed. This also means the feeder is faster per feed. But it also means the second part might be left exposed (cover film already pulled off) when the job finishes. So when you remove the feeder from the machine, it will certainly fall out and get lost.

> and the locations of the 2 exposed parts are nicely found by the vision calibration.

Actually the vision does not detect the parts, but only the sprocket holes. It derives the pick location from the settings and from inherent geometry given by the EIA 481 standardization. For the 0402 and 0201 parts, it will automatically alternate the pick location between the two 2mm pitch pockets. This is also visualized with these yellow numbers whenever a vision op runs:

And you see it in action here (this is the all-3D printed push-pull feeder, but it would be the same for an electrically actuated feeder):
https://youtu.be/5QcJ2ziIJ14?t=255

Unlike the perfectly round sprocket holes on an even background, parts are very hard to detect in computer vision, as they all look differently, one would need to "teach" and store "template images" with time consuming user assistance, there would be complications with shiny parts, slight rotation and different edge shadows inside the pocket wiggle room, transparent and reflective plastic tape, etc.

_Mark

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