strip tape holder

[Trampas Stern]

I would like to make a strip tape holder that is about 300mm (12") long.  I was looking at machine out of HDPE or other material and had a few questions:

First off has anyone done this already? 

What color base plate should I use? 

Is HDPE good enough, or MDF? 

For part alignment would adding alignment pins help? 

Is there a recommended spacing between part strips? 

others? 

For the color a concern I had was vision, however if alignment pins are used I am not sure vision will be needed? 

I want a long strip feeder as that I have some parts that are used a lot, but are expensive enough not buy reels.  Thus having a long strip feeder seemed like the way to go but open to suggestions. 

[Cri S]

You should look on jedec tray dimension first.
MDF is cheap and works fine, I'm using it unmachined gluing The strips down.

[Trampas Stern]

One problem I had gluing (double stick tape) is that parts like diodes and SOT23 where the bottom of strip is not flat have problems staying down. 

I was thinking about machining slots in the HDPE with screw holes in between for a clamp to hold tapes down. I know there are some 3D printed holders like this but these are usually not very long (200mm max), hence idea to mill. 

My thought was for high volume parts like decoupling caps, pull out a long section from reel place on holder. Then remove tape cover. After panel is built I would pull out more parts and reset the strip count and build next panel.  This would make a manual reel feeder system. 

Trampas  

[Cri S]

I usually use hot glue with a nail on one end for fix position and tensioning. Never had problems with sot23

[Michael Anton]

Someone reported in an earlier post that he had problems running long strips of tape, as the pitch of the pockets was not consistent enough over the long span.  Just something to be aware of...

[Paul Jones]

Here is one I made a few days ago:

http://a360.co/2oxood5

 

I was planning on having screws with washers or a strip of plastic to hold the tapes in place, but I 3d printed it and it was tight enough that the tapes held themselves in place. It works for every 8mm tape of passives I have.

In hindsight, I think it’s a much better idea to have a tight fit anyway, because the tapes come in so many different thicknesses. (0.15, 0.5, 0.7, 1.1mm just in my collection) Easier to hold from the sides than from the top, but that may not work so well if the sides are smooth (eg. Milled aluminium) rather than ribbed (3d printed) or furry (wood).

 

Paul.

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[Michael Anton]

How do you accommodate the variation in tape width?  The spec for 8mm tape says that it can be as wide as 8.3mm, but there is no lower limit specified.

I designed a 3D printed holder that spring loads the tapes from the bottom, so that it accounts for the variable tape thickness, and supports the tape well enough that the parts don't jump out of the pockets when a part is picked.  I really should get the design into a state where I could publish it...

[Trampas Stern]

How about this as an idea:

The basic idea is to cut holes using laser at 8mm spacing. Then as needed screw in self taping screws to create pins. The threads on the self taping screws create a ledge for the tape to hold to such that it does not pop out. However adding double stick tape will hold down the strip. 

By using long screws various part height, ie SOT23 for example can be used. 

The plate would be mounted to another piece of material, for example a 3/8" MDF which is routed out for access to screws from bottom and have the magnets. Optionally if we use M1.5 screws with small heads it might be possible to screw pins in from the top and not need access to under belly. 

Trampas

[Trampas Stern]

opps I meant 4mm spacing for the holes.  The final design might be Acrylic which is has less bow than plywood, but it is cheaper to prototype using plywood... 

Trampas

[Cri S]

I suppose you already know this:
https://lowpowerlab.com/2014/07/23/lasercut-strip-feeder-for-your-pick-place/

2017-03-29 17:23 GMT+02:00, Trampas Stern <tra...@gmail.com>:
> opps I meant 4mm spacing for the holes. The final design might be Acrylic
> which is has less bow than plywood, but it is cheaper to prototype using
> plywood...
>
> Trampas
>
> On Wednesday, March 29, 2017 at 11:18:44 AM UTC-4, Trampas Stern wrote:
>>
>> How about this as an idea:
>>
>>

>> <https://lh3.googleusercontent.com/-sCc9oL2bEQ4/WNvO-2AdKXI/AAAAAAABziA/lqayiPxVK0Y7I4K3hxhU7C7L_Ojsz1f0ACLcB/s1600/IMG_20170329_110805.jpg>
>>
>>
>> <https://lh3.googleusercontent.com/-8T32hcf_LQk/WNvPAgwaU4I/AAAAAAABziE/HF2gD-3zZcwX_FjEfz-3yHyK5M_iQpApACLcB/s1600/IMG_20170329_110813.jpg>

>>
>>
>> The basic idea is to cut holes using laser at 8mm spacing. Then as needed
>>
>> screw in self taping screws to create pins. The threads on the self taping
>>
>> screws create a ledge for the tape to hold to such that it does not pop
>> out. However adding double stick tape will hold down the strip.
>>
>> By using long screws various part height, ie SOT23 for example can be
>> used.
>>
>>
>> The plate would be mounted to another piece of material, for example a
>> 3/8" MDF which is routed out for access to screws from bottom and have the
>>
>> magnets. Optionally if we use M1.5 screws with small heads it might be
>> possible to screw pins in from the top and not need access to under belly.
>>
>>
>>
>> Trampas
>>
>>
>

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[Trampas Stern]

In OpenPnP it might be possible to setup the software to treat the strip feeder locations like yamaha slot feeders. That is you could have multiple "trays" of parts and pinned location on machine. Then when you swap out the tray everything should be aligned, at least close enough for vision, at which point you would just specify which part is in the slot. 

Of course you could have different width, for the moment my thought is larger width parts can cover holes for next row, but it is really up to you. 

[Trampas Stern]

Yes I saw that, Anthony had mentioned that he has to "stretch" parts to get right spacing for consistent pick locations. Hence the idea for using pins, or nails in MDF. Nails might work for pins in this design...  

So my assumption was that strip feeder has to:

1. hold strips parallel - Jason indicates having strips on one axis creates less error which makes sense

2. Needs to stretch/align part spacing - this way parts are consistent spaced on strip. 

3. Needs to allow easy changing of strip. 

4. Adapt to various strip widths.

5. Accommodate various height parts - SOT23 for example

6. Be easy to change out tray on machine - Maybe add a magnetic lid that covers parts (assuming parts on tray all have same height, or a cover per row... ). 

7. Be cheap and easy to make

8. Ideally allow vision system to work (holes in strips should be visible)

9. Have good part density - allows tape to be spaced close together (depending on vision) for maximum parts per square area. 

10. Easy reconfigured for various length strips. (finishing nails pushed through holes might be good). 

I still have more testing to do on this design and if it works I would be happy to cut some for people. 

Trampas

 

[Trampas Stern]

You can cover next row of holes for 12mm and 16mm tape widths. The width does not matter as this is just a peg board of alignment holes.  We could put the rows of holes 6mm spacing instead of 12mm I used just to increase options. 

[Cri S]

How many tray can you place on machine?
I suppose orientation is the same for all tray, is this correct?
Can you execute bsh scripts?

[Trampas Stern]

My machine is based on Anthony's design with 600mm rails, since I have no feeders at the moment I can fit quite a few.  My working area (where both nozzles and camera can see) is around 420x420mm.  

I figure I could place 6 trays if need. However I have not nailed down all the mechanics yet to figure out the machine layout. I want to get feeders in place  before allocating real estate for trays.  

[John Socha-Leialoha]

Some time ago I designed a set of 3D printed holders that adapt to different part heights and can be built for different tape widths:

https://www.youmagine.com/designs/smd-tape-strip-holder-8mm-12mm-16mm-24mm

or

http://trains.socha.com/2017/02/making-smt-tape-holders-part-i.html

I've also been working on making an injection molded version. The goal is to make them available for about $10 each. I have a test mold for one of the four parts, and I'm just about ready to start making the production molds (making injection molds and parts is a hobby of mine). I'm not sure yet when the injection-molded versions will be available, as I just broke my leg while playing soccer, and the doctor says I can't put weight on my leg for 6 weeks. Grump. But my hope is within the next three monthds.

[Paul Jones]

I quite like that design. I’m going to give it a try.

Just an idea for the injection moulded version – If you could put some sort of clip or slide-lock mechanism so that multiple units can be joined without using threaded rod or screws that would be great. I can’t think of any easy way to do it that could be printed.

 

Paul.

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[John Socha-Leialoha]

We had a long discussion about this on the LitePlace forum: http://liteplacer.com/phpBB/viewtopic.php?f=11&t=399&start=50

The idea is to use steel plates and thumbscrews or thumbnuts to lock the holders in place. Does that address the problem you were thinking of?

The discussion is in the LitePlacer forum, rather than here, because Juha, the owner of LitePlacer, reached out to me about making an injection molded version after seeing my 3D printed version. I got some quotes for the injection molds and making the parts, and they were higher than I expected for such simple parts: $30,000 for two molds here in the US, and $15,000 for two molds made in China. Prices have certainly gone up a lot since I last had molds made 10 years ago. They also quoted $15,000 to make 5,000 sets of parts, which also seemed high. So I decided to make the molds myself, and hire a friend of mine after hours to make the parts. The advantage is that I have complete control of the process. The disadvantage is that it takes longer, by a few months.

I also decided to share the entire process on YouTube, which is a lot of fun. That also means you can keep track of my progress by subscribing to my channel (shameless plug).

On Saturday, April 1, 2017 at 2:05:58 AM UTC-7, Paul Jones wrote:

[Paul Jones]

That wasn’t quite what I was thinking, but it’s a better idea anyway. I was thinking something like how lego blocks clip together, to hold all the feeders together, but then they wouldn’t be properly indexed.

 

Paul.

 

From: ope...@googlegroups.com [mailto:ope...@googlegroups.com] On Behalf Of John Socha-Leialoha
Sent: Sunday, 2 April 2017 2:29 AM
To: OpenPnP <ope...@googlegroups.com>
Subject: Re: [OpenPnP] strip tape holder

 

We had a long discussion about this on the LitePlace forum: http://liteplacer.com/phpBB/viewtopic.php?f=11&t=399&start=50

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[bobgee...@gmail.com]

John,

I am also very impressed with your design and would like to try it. I don't have a 3D printer yet so I was going to give this website a try: www.3dhubs.com

I was planning to just get one set of 8mm at first to see how it works.

Do I need all four 8 mm parts or are the "mirror" parts for facing the other way on the bed?

I tried to look at the parts in a browser based stl viewer, and they didn't appear to be a mirror image but perhaps I didn't view correctly.

Also, is "prototyping" plastic good enough? I want to keep costs down if possible. I get that you reccomend 0.2 mm layers, but other than that is PLA on a prusa i3 (for example) good enough?

Can I also ask about your designs for a holder that you just linked to. Would laser cut acrylic be ok for these parts? Are the designs for these out in the wild yet?

Finally, can you tell me the heigth of the tape from the bed when in your holder? I want to design a pcb holder and get that printed too, maybe also a simple chip tray, all at the same height as the tapes, is that wise? Is there already anything out there I should try first, i.e. what do you use to hold your pcb and chips, when using your feeders?

Many many thanks

[John Socha-Leialoha]

Thanks. I realized I didn't include a link to the discussion here about the 3d printed version: https://groups.google.com/forum/#!topic/openpnp/fPgTmROUzns

The height from the bottom to the top of the tape is 23 mm. You will need all four parts as they're not the same. The names of some parts say "Mirror" because SolidWorks added that to the name (it has to do with how I created the parts). I used PLA, which I think is a better choice than other plastics in this case. PLA is easier to keep flat while printing, plus it's plenty strong enough. Nothing about these parts requires a lot of strength.

I'm not sure which design you're asking about regarding laser cutting. None of my designs can be laser cut, as that would be a very different design (I've done lots of laser-cut designs).

I realized that there are some more part files I need to put up on YouMagine. I have some PCB holders I created that are at the same height. And I have the end parts that help hold a rack of strip holders in alignment against the side of the machine. I'll try to get those uploaded sometime today. I'm less mobile than before because I'm in the early stages of recovering from a broken leg (soccer).