Modular feeders + tray for cut SMD strips and single parts

[mrandt]

Hi everyone,

I would like to present my idea for modular feeders and a tray to hold cut SMD strips and individual parts.

My objectives are as follows:
- I usually buy parts in smaller quantities (cut strips), so no point in having fully automated reel feeders (at least not yet...)
- I use both paper (8mm) and embossed plastic tapes (mostly 8, 12 and 16mm), also some loose parts (e.g. ICs in TQFP or other packages, connectors)
- I want to be able to easily "load" parts onto my LitePlacer without having to mess around with double sided tape or the like
- I want to be able to configure a tray of components for each different PCB panel I produce, so I can switch between different jobs by just replacing the tray and reloading a set of tape definitions and part positions (-> tray definition) without teaching LitePlacer software all locations again
- In some cases I may want to have multiple identical trays, so I can "preload" one tray while the machine is placing from the other. Once I run out of parts, I simply switch the tray, reducing down time and increasing productivity.

My solution to this point:
- 3D printed part holders for different types of tapes and parts, easy and cheap to make
- tapes are being held down by rails (also 3D printed), pressure is adjustable with screws to create just enough friction to hold tapes in place
- modular "Lego-like" system to combine multiple of these holders on a laser-cut steel tray
- uses magnets to fix 3D printed holders to tray and centroid / index pins to align them and thus make configuration "repeatable"
- 4/8mm grid to ensure parts are always aligned in a predefined pattern
- optional centroid / index pins on LitePlacer table allow to always position tray at the same spot

Pictures of CAD construction at this point:

Fullscreen version: http://liteplacer.com/phpBB/download/fi ... iew&id=162

mrandt_stripfeeder_tray_01.jpg (132.96 KiB) Viewed 11087 times

Fullscreen version: http://liteplacer.com/phpBB/download/fi ... iew&id=163

mrandt_stripfeeder_tray_02.jpg (65.61 KiB) Viewed 11087 times

Fullscreen version: http://liteplacer.com/phpBB/download/fi ... iew&id=164

mrandt_stripfeeder_tray_03.jpg (54.93 KiB) Viewed 11087 times

Fullscreen version: http://liteplacer.com/phpBB/download/fi ... iew&id=165

mrandt_stripfeeder_tray_04.jpg (38.64 KiB) Viewed 11087 times

Fullscreen version: http://liteplacer.com/phpBB/download/fi ... iew&id=166

mrandt_stripfeeder_tray_05.jpg (19.39 KiB) Viewed 11087 times

Feedback is welcome, let me know what you think

Best regards
Malte

[JuKu]

Nice, very nice!

The software already supports these. Due to the Maker Faires, I haven't had time to document it yet, though. Still, I think/hope it is rather obvious how to use the feature(?).

[mawa]

Just a short question:

Malte, how many of those - let me call them "tray assemblies" (the silver base with the tape strip feeder and single part trays) - will you be using around the pcb placing area?

[mrandt]

how many of those - let me call them "tray assemblies" (the silver base with the tape strip feeder and single part trays) - will you be using around the pcb placing area?

Hello Manfred,

the steel plate (tray) design is 220 x 200 mm. On my machine I could fit three of those next to each other (along the X axis) behind the PCB area. My LitePlacer's work area is slightly larger than Juha's kit. I could fit another one or two next to the PCB panel (to the right) if needed - so probably five trays in total.

The "part holders" I designed come in two different sizes - either 98mm or 198mm wide but they all align well with the same 4/8mm grid.

Using a tape with standard part distance (4mm center to center), the small holder will keep 25 and the large 50 parts per rail. Depending on the tape width, each holder has 4, 3 or 2 rails.

Per tray, I can fit three large or six small holders (or combination of those).

I looked at a few random boards I have made recently and determined that one or two trays should be sufficient to hold enough parts to populate a complete panel in one go. Usually my panels only have about 5 to 10 boards as I only have a small reflow oven.

Hope this helps - will keep you posted about my progress.

Cheers
Malte

[mrandt]

Hello,

I received the steel trays, magnets and pins and have 3D printed a few of the suggested strip feeders.

So far, I made some for 8mm paper tape, 8mm + 12mm embossed plastic tape and TQFP44 chips.

The feeders are printed from ABS while the cover rails are made from Taulman "Bridge Nylon" - which is very strong (even thin parts are almost impossible to break) and a bit flexible as well.

The magnetic link to the plate works great and centroid pins allow for repeatable positioning of plastic parts.

I intend to put additional index pins on my LitePlacer's table to also predetermine the position of trays but still have to make up my mind where to put them... Another idea would be to put "fiducials" on the metal tray and use down camera to determine position and potentially rotation of a given tray - similar to the correction performed for the PCB.

The panhead screws can be adjusted to create just enough pressure and friction on the tapes to hold them in place.

Removing the clear cover tape works without a problem after inserting the strips and positioning the tray.

Sprocket holes are still visible but in some situations I would prefer to teach the machine first and last part position and give the spacing - just as many commercial machines work with strip feeders. Also, I would only need to do this once per tray.

Juha's latest software release already enabled me to save the component locations per tray and reload them as needed - what a nice coincedence

But pictures sometimes speak more than words - so see for yourself

mrandt_mod_strip_feeder_01.jpg (53.01 KiB) Viewed 10909 times

mrandt_mod_strip_feeder_02.jpg (30.48 KiB) Viewed 10909 times

mrandt_mod_strip_feeder_03.jpg (52.21 KiB) Viewed 10909 times

mrandt_mod_strip_feeder_04.jpg (64.14 KiB) Viewed 10909 times

mrandt_mod_strip_feeder_05.jpg (55.45 KiB) Viewed 10909 times

mrandt_mod_strip_feeder_06.jpg (36.07 KiB) Viewed 10909 times

mrandt_mod_strip_feeder_07.jpg (58.45 KiB) Viewed 10909 times

mrandt_mod_strip_feeder_08.jpg (91.78 KiB) Viewed 10909 times

mrandt_mod_strip_feeder_09.jpg (91.76 KiB) Viewed 10909 times

[mucek]

Damn ... Now I see all those beauties, when I sold my 3D printer in order to buy Liteplacer!

Regards,
Gregor

[ameli]

This is such a convenient and well thought out design. How can I get my hands on one? Will you sell the parts or release the CAD files? Excellent work!

[Spikee]

My design works great for resistors and small caps but when using larger components this does not fit.
I will be making this kind of tray to combat that.

[Pixopax]

I also thought of making Trays for my parts, and started to experiment a bit today.

I milled a small demo tray, for holding the strips I have a 1mm Fiberglass-Part, which lets the holes visible.

Would that work for the vision system, or would it confuse it?
I also thought of milling just the holes in the cover, an index pin would let me fix the strip so the holes in the cover would match with the holes in the strip.
That way, the vision system could also clearly see the holes when a clear strip is loaded.

[mrandt]

Hi Louis

I milled a small demo tray, for holding the strips I have a 1mm Fiberglass-Part, which lets the holes visible.
Would that work for the vision system, or would it confuse it?

The vision system is looking for circles. I think the cutouts will not distract it. But you need to have high enough contrast.

Two suggestions:
- use a different color for the part holders, otherwise you will not have enough contrast when using black tape
- green or blue works nicely with all tapes (paper, black and clear plastic)
- mill the top cover from opqaue material of same color as the base
- try to find material that is less relfective / glossy or sand it slightly to make it appear matte as reflections might confuse your camera

I also thought of milling just the holes in the cover, an index pin would let me fix the strip so the holes in the cover would match with the holes in the strip.
That way, the vision system could also clearly see the holes when a clear strip is loaded.

Yeah, index pins are nice as they ensure tape is always in same location.

Instead of dealing with the camera detection of the holes, you might want to try Karl's version of RMod fork of LitePlacer software.

It has two interesting features:
a) Detect the parts, not the holes, based on a sample picture (holes does not have to be visible at all)
b) Teach machine the center of first and last part location on a tape and have it figure out the location of the parts in between (holes again do not have to be visibile; is also a lot faster than using CV on each and every part before pickup)

The latter would works nicely if you can ensure tapes are alway in same position in holder (index pin) and in turn the holders are always in the same location on the table (one reason for my steel trays) - because you only have to teach locations once and can simply refill spent tapes.

Cheers
Malte