Add-ons: feeders

[Spikee]

I have heard some bad things about about makerbot. There is at least one class action running against them about build quality.
Dave jones from the Eevblog also seems to have some issues with his. Tbh for the money I would just go with a new or second hand ultimaker 2.

[Knas]

For switches to use for hole detection these are perfect both size and price-wise.
http://www.mouser.com/ProductDetail/ALP ... vFwinV4%3d
i was going to use them myself in an earlier prototype.

Karl

[Spikee]

Those are some nice switches.

On youmagine there is a feeder desing that uses a lever to forward the strip via the holes.
Might pay to print that one once.

https://www.youmagine.com/designs/open- ... ape-feeder
Add a cheapo servo to it and it should work ...

[mrandt]

Might pay to print that one once.

I honestly think that would be a waste of time. I've seen that design before and believe it is a prototype - at most...

I doubt a printed sprocket wheel will stand up to the task long. Maybe if made from nylon... But not PLA or ABS.

How to remove the cover tape? Maybe that could be done with pulling weights, but than you'd need some sharp edge to pull it around - and ensure the tape is not advanced by the force.

I also think that the lever and spring will cause too much shock - so smaller components will jump all over the place (try 0603 or 0403 with it).

That design and the Google Code project linked to in the description have not seen any activity in years...

I think your own design is more promising

BTW: I guess you've seen Protovoltaics feeder design?
http://blog.protovoltaics.com/diy-pick- ... ce-part-2/

They have very well designed mechanics for the sprocket wheel, tape winder and electronics - but also more complex and expensive to build.

Edit: Nevermind - I just saw that this was already referenced in an earlier post in this thread...

[mrandt]

Hoi Spikee,

I just stumbled across a picture of the cover tape transportation system from inside a commercial feeder:

https://groups.google.com/d/msg/openpnp ... VGqWcCJcUJ

I assume something like this might work in your design instead of using a spool - and would have advantages:
- Works forever without changing / unspooling spool
- Tape advance is constant amount per revolution; could eliminate the need to have a sprocket hole sensor

Vriendelijke groet

Malte

[Spikee]

What I see on the picture is that they are using "gears" to advance te tape. And they are rolling it up on a spool somewere else.

This method removes the "error" in my design when a significant amount of tape is rolled up.

I would still use some kind of hole sensor just for checking... but this is quite a good method.

Now ... which gears are needed to make this work good on a smaller scale... thats the question

[mrandt]

This method removes the "error" in my design when a significant amount of tape is rolled up.

That's what I thought

And they are rolling it up on a spool somewere else.

Well, they might - or one just might just leave the loose end hanging somewhere, maybe add a little weight - or use a very simple spool drive, e.g. motor and sliding clutch, even springloaded might work.

which gears are needed to make this work good on a smaller scale

I don't think they necessarily have to be gears. A pair of rubber wheels might work just as well. Attach one wheel to the geared motor, leave the other one as an idler which pushes tape against the first wheel using some springy mechanism.

[Spikee]

Knex / lego wheels to the rescue ... Might just try it this weekend
What the gears offer is a better grip in my opinion. Sometimes you have some really sticky tape when using cardboard/paper 8mm reels.
Just a wheel mechanism might not work correctly in that case because the rubber just can't get enough grip.

Also small timing pulleys are probably cheap as chips in china

[a2retro]

I have seen the protovoltaics feeders mentioned earlier in this thread and they are on kickstarter now and have said they will open source their design. MIght be worth looking into.

[mpbrock]

My friend has one of these NeoDen TM-240A - i was watching it yesterday - (some videos of it in use on Youtube) - it has quite a novel way of advancing the tape from the feeders - no motors - a needle comes down from the PnP head above where the holes in the tape are, and then it drags some more tape out from the reel, before the needle retracts and it then picks up the components.

I quite like the simplicity of this idea, but i'm not sure what others think? I thought it would be quite easy to 3d print some spool holders and a needle for the LitePlacer head to add this sort of mechanism?