
From Desktop 3D Printing to Desktop Electronics Manufacturing - emilyn
https://blog.octopart.com/archives/2015/11/from-desktop-3d-printing-to-desktop-electronics-manufacturing
======
jonmrodriguez
Let me start by saying that I agree that desktop electronics manufacturing
will be the "next big thing" in the maker movement, and I am a huge fan.

However, this article does not mention two very important issues. In order to
make a circuit board of any interesting complexity (i.e. more than an Arduino
and a few LEDs), you need more than 2 copper layers to route your traces on.
And, you need VIAs (Vertical Interconnect Access), which are columns of copper
that make electrical connections between the layers.

I have used a PCB mill and while it is very useful for making extremely simple
circuits, it only lets you mill 2-layer boards, and it does not let you make
VIAs (instead you have to manually drill a hole through the board and solder a
pin into the hole, and this approach has a much much larger diameter than a
real via).

In order to be interesting for "maker" goals such as Linux machines, IoT, and
robotics, there needs to be a desktop fab solution that can _at the very
least_ make 4-layer boards, with VIAs.

~~~
Htsthbjig
"via" comes from latin, it means " a place to travel trough".

For example in Spain "autovia" means via for autos or "tranvia" means a
vehicle that goes over rails. "Via pecuaria" means a road for animal
transport.

You can do lots of useful things with just two layers. We prototype
professional electronics in house with just two layers and modules(over a big
area), then shrink the design, use more layers and get it done using a
professional service.

------
yitchelle
This describes the one of the first places I worked at. It started as small
contract manufacturing house before becoming a significant player in this
space. However, one thing is clear, the amount of manual work involve does
reduce the consistency of getting good results, ie the amount of solder paste
squeeged onto PCB is not controlled, the placement of the components are also
not well controlled etc.

However in the maker space, this option is great! Fantastic for getting a
small production run out the door!

------
msds
For decently capable(1) desktop manufacturing,"desktop" is a bit of a misnomer
at this point. I've found that you need at least three desks, not to mention
another desk for all of the test gear, and another for mechanical prototyping,
and another for...

At this point, I have(2) an othermill and a pretty-near top-of-the-line LPKF
S63 system + silkscreen and reflow capabilities, and am fairly impressed by
both. I've been able to go from opening up a PCB editor to having a tested,
functional board in under an hour, at least for simple breakouts.

The othermill is pretty flawed for PCB work, however. The spindle just isn't
fast enough, cross layer alignment is inadequate, it doesn't have dust control
for dealing with FR4 dust, etc. For good PCB routing, some sort of computer
vision system for adjusting cut depths and picking up fiducials is also
amazingly handy. That being said, we're really impressed with our othermill
and do a lot of mechanical work on it - complex aluminum parts, engineering
plastics, etc.

Cheap soldering for one-offs is pretty much solved at this point - laser cut a
stencil on a decent laser cutter (which everyone should have, anyways),
stencil paste, and reflow in a cheap Chinese oven with open source aftermarket
firmware. You won't be able to do big BGAs or tiny (0201) passives, but who
cares? If you have soldermask capabilities, either some photoresist method or
laser cut kapton, soldering tricky components becomes much easier.

None of the additive (ink-based) systems have any hope of producing really
useful boards - the electrical and thermal conductivity of real copper is
pretty hard to beat, and doing anything controlled-impedance is pretty much
out of the picture. With subtractive systems, you can just switch to 8+ oz
copper or exotic substrates without changing the process materially...

Vias are tricky. LPKF makes two systems, one with conductive epoxy and the
other with electrochemical copper, neither of which are quite satisfactory.
Via rivets (or manually soldering wire) work for small boards, but are super
tedious and not great for controlled impedance applications, either.

Being able to do decent multilayer boards is contingent on good vias, but in
theory, the only other thing you need is a hot press for stacking things up?

Once you get into building complex multilayer boards, the time investment is
just silly, even with perfectly calibrated processes, and you should just
order from a board house and wait...

(1) I.e. boards better than DIY etching + manual soldering.

(2) Well, they're not actually mine, per se...

