SMD Parts Tray Shoot Out: Who's the Winner?

[robert@serve101.org]

I received a request for more detail about my parts trays. So here goes... (File this under "If you have a hammer, everything looks like a nail"): I am lucky enough to have a Carvey, which is a small CNC milling machine. I used that to create the parts trays.

0805 parts: The material I used was two color acrylic 1/16" for the 0805 Caps and resistors. First I made grooves of 8.4mm wide, and then made the end strips. The end strips are attached using double sided sticky tape, and they have grooves on the underside to allow the tapes to slide easily. One advantage is the rulers can be engraved into the material. At first I used tape at the bottom of each groove, but later found it much better to use one-sided tape on top. You need to hold the part-tapes down well, otherwise, the tape with bounce a bit when a part is extracted. This is very bad, since the bounce makes nearby parts, not yet picked, go flying.

Small parts in clear plastic tape: I used two color acrylic, but 1/8: thick for these. Since I find it hard to get reliable contrast on clear tape, I engraved reference circles as part of the ruler. Another trick was to mill cavities so the parts tapes are held in a consistent position relative to the engraved circles. Then it's just a matter of adjusting the part's offsets from the engraved holes, in my case x=5mm y=0mm

Large parts in clear plastic trays; I used basically the same technique as the small parts in clear plastic, but attached 1/16" two color acrylic on top of 1/4" HDPE, so I could mill much deeper cavities.

small parts in black plastic tape: I used the 1/16" two color acrylic for these, milling groves such that the tape fits snugly in them, in some cases eliminating the need for two sided tape. Once again I was able to engrave the rulers and also part numbers in this case.

Loose parts: These are on the same sheet of 1/16: two color acrylic, milling cavities so that the parts just fit to ensure repeatibility.

[mrandt]

Robert, your solution looks very clean and is probably very effective, too

Could you post a picture which shows the reel holders as well? To me that is an interesting aspect; always concerned with the workflow to "refill" the holders...

Can I assume that your setup (at least the board for the individual parts) is rather specific to a given PCB / job? Do you just make new holders when different parts are needed?

One more thought: When I saw the calibration / aiming mark on your tray, I immediately thought it should be possible to put several "fiducials" on your holders - both the strip / feeder holders and in particular the big tray on the right. That way we could tech the pickup locations very effectively to the software.

It would basically be the other way round than the placement. Load a coordinates-file which contains three fiducials and the pickup locations of all the parts on that tray. They will be in very predictable positions relative to those fiducials... The same could work for the strip feeder holders up north in your picture. In that case, two fiducials would suffice - and those would allow to find the starting position for tape sprocket hole detection.

I am not sure how difficult it would be to add the necessary logic to LitePlacer software though. Will think more about it and also crosspost on OpenPNP forum.

By the way, I just saw yet another approach on OpenPNP:
https://groups.google.com/d/msg/openpnp ... BmLd4PAwAJ

There is also a YT video:
https://www.youtube.com/watch?v=yKC1ie7pASw

Actually the basic shape is quite similar to my trays; also the index pin. What's different is that those here are milled from plastic (faster and maybe more precise to make) and mounted firmly to a JDEC tray holder. A fancy idea is the use of brushes to eliminate part movement / vibration.

[robert@serve101.org]

IMG_1530.JPG (541.01 KiB) Viewed 5179 times

Robert, your solution looks very clean and is probably very effective, too

Could you post a picture which shows the reel holders as well? To me that is an interesting aspect; always concerned with the workflow to "refill" the holders...

Sure, but I did not do anything special. Some of the parts simply cacade down the back side of the table into a box. Some wrap around the back "axle".

Can I assume that your setup (at least the board for the individual parts) is rather specific to a given PCB / job? Do you just make new holders when different parts are needed?

I consider my parts layout to be sort of my inventory. I have a half a dozen boards that are made from those parts. If some project needs something not on my "standard" list, I can add that as an additional loose part.