[time-nuts] OT stuffing boards: was GPS interface/prototyping board

Attila Kinali attila at kinali.ch
Fri Jun 24 10:32:48 EDT 2016


On Thu, 23 Jun 2016 20:16:34 -0500
Oz-in-DFW <lists at ozindfw.net> wrote:

>  1. Pick and place machines use a lot of floor space (even for the
>     "small" ones are more than 1/2 a bench.)
>  2. Even the best ones require pretty continuous tuning. If you aren't
>     using them continuously each new run is a new and different
>     experience.  Often unpleasant for the first few scrapped boards.

The trick is to use semi-manual pick&place machines for low volumes.
Ie machines that you do not program, but guide by hand. This allows
faster and more accurate placing of components than would be possible
with a pure manual process, but does not have any of the complexity
of the fully automated solutions. The components do not need to be
100% exactly centered, as the surface tension of the molten solder will
pull the parts into place (which is also the reason why the copper inside
the solder resist mask should be symmetric).

These machines are still all pretty expensive (IMHO, the cheapest
start from around 2kusd IIRC), but with the continuous growth of the hobbyist
market, and that market becomming more and more professional/proficient,
the production volumes of these  machines will for sure rise and thus become
cheaper. I am pretty sure that we will see hobbyist marketed pick&place systems
build upon open source based control systems in the next couple of years.
There are already a couple of DIY systems out there, that look quite good.
e.g http://vpapanik.blogspot.de/2012/11/low-budget-manual-pick-place.html
http://www.briandorey.com/post/Diy-Manual-Pick-and-Place-Machine-part-1


> Solder stencils make **all** the difference.

Oh, yes! Please, do not try syringe dispensers! These fail more often than
they work. Also pay the additional couple of bucks to get a steel stencil
instead of a kapton one. Especially if you make more than one or two boards
or those with fine pitch.

			Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
                 -- Miss Matheson, The Diamond Age, Neil Stephenson


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