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Desktop Pick-&-Place Machine: An EETimes Community Project

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Aeroengineer
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Re: Interesting
Aeroengineer   6/18/2014 10:14:45 PM
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Thanks for your detailed input.  As you mentioned the feeders and how ling parts are stored in that feeder can be problematic. This along with the size of the components that you mentioned will put some bounds on what one may want to do with this machine.  I am thinking that 0402s are going to be the target size for these components.  There are going to need to be certain limitations that are not typically encountered  for volume production, but then again, this is not geared towards that world.  One of the things that could be done if really necessary for moisteure is to have a drying routine.  I have not looked into it too much for electronics, but I know that for many dry composite materials, we do a 150 degree F for an hour to remove any moisture.  I know that I have seen some drying procedures for electonic components, I just have not had to deal with them yet.

 

As to the thermal issues that you mentioned, one of the things that I am looking to mitigate some of these things are the use of materials in the mechanicals that are matched to the Cte of FR4.  Standard Steel or Stainless Steel would be the materials of choice to match the approx 6-8 microstrain perdegree F of the FR4.

 

Please, though, keep the ideas coming.

Thinking_J
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Re: Interesting
Thinking_J   6/18/2014 9:16:01 PM
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fun project..

Wish you luck ..

Having been in the industry for some time.. I would like to point out some of the most commonly over looked issues that a project of this type would have:

- component storage .. soldering sufaces on components do oxidize and plastic components absorb moisture from the air. Most hobbiest are not prepared to keep components in a low moisture atmosphere during times the system isn't running.

It only takes a few days of exposure to high RH.. then you have to "bake out" the parts. If you don't, the parts will "pop corn" during solder reflow (drive the moisure out too quickly).. a real issue for many thinner SMT packages

- solder paste knowledge. If you plan on building with smaller parts the solder stencil opening become very small (fine pitch BGA, etc..) the quality of the solder paste become critical - and it solder paste is expensive! Generally best practice is to keep refrigerated - too keep the flux from going bad. This is an issue regardless of the method of applying the solder to the pcb (stencil, direct deposit, etc..)

- For the desired desktop space mentioned.. your component feeder/submitting system will be the hardest part of the system's mechanical design. Tape and reel feeders can be small , but I don't think you could get very many components "on-line" in the space mentioned. Bulk feeder system can be small , but only work for passive components..

- Reflowing single, simple boards in the same space will have another problem. The impact of heat on the accuracy of the placement. I have a quality SMT line, and we cycle the machines for awhile - then calibrate their placement accuracy with a zero temp coeffient optical target based on the thermal expansion of the machine. .. and I only consider it good enough for 0201s.

Best to keep the furnace/oven separate.... regardless of if you can put it in.

For prototypes: I would recommend use of conductive epoxies instead of solder for your design goals... it would reduce or eliminate many of these issues.
 Easier to dispense, no high temperature excursions to subject components to, less sensitivity to oxidation on connection points.

Aeroengineer
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Re: Interesting
Aeroengineer   6/18/2014 8:09:58 PM
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No, please keep the input coming.  I think that you are seeing why we are branching out on our own.  There are some reallyunique things that can be done within what we are trying to do. 

 

Your feeder system for example is somewhat similar to one of the concepts that we have batted back and forth.

 

Being able to add the oven feature will also be able to really add functionality to this to be a one stop machine for turning small proto boards in say half an hour to an hour.

 

 

Aeroengineer
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Re: Desktop pickup and place
Aeroengineer   6/18/2014 8:07:16 PM
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Glad to see that I am not the only one that functions well with a little clutter on the desk ;)

Aeroengineer
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Re: There are already some Low Cost PnP Projects
Aeroengineer   6/18/2014 8:06:20 PM
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Thanks for the comment.  I am sure that there are things that can be leveraged off of these efforts, but there are some fundamental aspects that we are seeking to improve upon.

 

One of these areas is to completely eliminate the style of feeders that are used.  There are two reasons for this.  First the cost.  Feeders drive significant cost into the designin a few ways. Their mechancial nature makesthem expensive to produce, and because you need to have a lot of them for building any sort of board, this further increases cost.  The other issue with this style of feeder is that they significantly increase the footprint of the device.  I think that we as a group can do better while only suffering some minor tradeoffs

 

This is not to discourage posting other references.  We are always open to reference material.

 

Adam

Aries1470
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Interesting
Aries1470   6/18/2014 7:20:44 PM
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Hi,

Well, here are my 2¢ worth.

For feeding, instead of having the huge things - aka feeders for large runs, why not implement an 'old style' dot matrix printer feeder, but with adjustable width spokes.

Then on the side, depending on the maximum pcb workable area, have an attachment, that will be a small oven, with side walls that can open and close, as to save space and energy.

I can input more, but... some others have referred to other projects.

tb100
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Desktop pickup and place
tb100   6/18/2014 6:44:09 PM
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The way my brain works: when I saw "desktop pick and place machine" I immediately thought of a robot that you put on your desk which cleans up your desktop. The question is, after it has finished placing everything, will I be able to find anything?

Kirby2008
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There are already some Low Cost PnP Projects
Kirby2008   6/18/2014 6:26:36 PM
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Good day,

There are already some low cost PnP projects started and so perhaps it would be best to work with these groups, as opposed to starting another one.  Here are some that I have found:

http://hackaday.io/project/963-%24300-Pick-and-Place-%2F-3D-printer

http://briandorey.com/post/DIY-Pick-and-Place-V2-Project-Complete.aspx

https://github.com/openpnp/openpnp

http://www.placecomponents.com/

http://www.vbesmens.de/en/pick-and-place.html

Cheers,

Sam

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