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

[Mark Sims]

I have seen pick and place systems built around  CNC machines (same applies to 
3D printers).  The reel strips are fed through a slotted guide.  The pickup 
head has a finger (or some use the pickup nozzle... a flat tipped hypodermic 
needle) that is used to advance the reel.  It drops down into the component 
pocket on the reel (or the index holes) and pulls the strip forward one pocket 
length.  This movement also peels back the tape cover strip.  The nozzle moves 
to the center of the pocket,  sucks up the component,  rotates it,  moves to 
the position on the PCB, and places the component.

Translating the design files into gcode commands for the required head 
movements is a fairly trivial bit of code (says the man (me) who wrote a 
90,000+ line C program that can translate between the dialects of over 100 
different CNC machines, 3D printers, and CAD programs).

Vision system is nice,  but a decent CNC is more than accurate enough for 0402 
sized parts.  Again, surface tension is your friend.

  
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Re: [time-nuts] OT stuffing boards: Saving the thread

[Bill Hawkins]

The problem is editing out all of the redundant material. It's tedious
by hand.

Anyone got a program to do that? Say, in perl . . .

Bill Hawkins

-Original Message-
From: John Ackermann N8UR
Sent: Friday, June 24, 2016 1:36 PM

You know, this thread has had a tremendous amount of practical
information, with actual URLs, etc.
Would someone be willing to consolidate the info on a web page
somewhere?


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[time-nuts] pick and place problems/design (was: OT stuffing boards)

[Attila Kinali]

On Fri, 24 Jun 2016 13:59:58 -0500
"Graham / KE9H"  wrote:

> Lots of problems to be solved...

Most of these problems are easy:
 
> How do you take loose parts or cut tape or tape reels

You don't. No loose parts with any kind of pick machine.
As for cut tape, these can be taped on an empty reel to make
them compatible. Everything has to be in a tray, reel or similar.

> and get the right
> part out, and into the chuck, oriented in the right direction?

Orientation is defined by the reel/tray the parts come in.
This is also documented in the datasheet, usually.

> How many different kinds of parts, sizes, shapes, pin counts, IC
> footprints, can you handle at once?

As many as there is space around the machine :-)

> How do you know it is the correct part?

You put it manually in the right feeder and double check that it
fits the programming.

> How do you know where the "+" end, or "pin 1" is?

This comes with the orientation of the part in the reel/tray.

> How do you know that there actually is a part in the chuck?

Your trays are guaranteed to be non-empty by manually loading them.

> How do you know the part in the chuck is oriented the way you expected it?

The manufacturer guarantees that the reels/trays are loaded correctly.

> How do you know where the footprint on the circuit board is located? (to a
> few thousandths.)

This is provided by the pick file. Usually its 3-5 digits after the
decimal point, when using mm. But as I wrote before, you don't have to
place part hyper exact. Being within 0.1-0.3 of the pitch of the part
is usually enough. Surface tension does the rest.

> How do you know the part left the chuck and ended up where you intended it
> to be?

You dont :-)

The way how this is checked is either a pre-solder and/or post-solder visual
inspection. This is either done manualy or using a camera system where
computer compares the PCB to the picture of a known-good PCB.
As this is ment for a small volume and hobbyist system, doing the visual
inspection manualy is good enough and more than fast enough.

Attila Kinali
-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

[Attila Kinali]

On Fri, 24 Jun 2016 12:41:05 -0500
Oz-in-DFW  wrote:

> On 6/24/2016 8:23 AM, Attila Kinali wrote:
> >  The advantage of "professional"
> > companies like Alktech over "hobbyist" companies like macrofab is,
> > that you get full professional support while the price does not differ much.
> > E.g. while macrofab only does 4 layer boards if you specially ask for it,
> > for Alktech getting any number of layers is standard procedure.

> Just to correct a misunderstanding. Macrofab, Small Batch Assembly, and
> PCB:NG are all professionals, not hobbyist companies. they focus on
> small runs at low cost, but they are manufacturing professionals with
> commensurate results.

Oops... sorry. That was a bad choice of words. What I meant was that
some companies targed hobbyists while other target professional customers.
These two customer groups have slightly different needs and requirements
for cost and provided service. And these differences are visible when
buying from those companies

Attila Kinali

-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

[Chris Albertson]

On Fri, Jun 24, 2016 at 9:52 AM, Don Latham  wrote:
> I do not see why a small pick and place assist system could not be built on a 
> 3-d printer.

You are not the first to think of this.   But the problem is
  1) moving the reels of parts,
  2) programming the machine.  Translating the PCB design files into g-code.
  3) Building a vision system.  With very small parts you really can't
run open loop



-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

[Adrian Godwin]

On Fri, Jun 24, 2016 at 3:32 PM, Attila Kinali  wrote:

>
> The trick is to use semi-manual pick 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).
>

For what it's worth, I have a manual / guided pick and place machine
available. UK pickup only unless you're really keen ! Off-list please if
anyone's interested.

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

[Mark Sims]

I've done a over one  hundred boards with a Kapton stencil without any problems 
(0603 size parts)  and 50 boards with a stencil cut out of vellum paper (a 
plasticized paper available at craft stores,  red cuts very well with 405nm 
lasers) by my home-made laser cutter head for a desktop CNC mill.   I've never 
worn one out or ripped one... YMMV.   I'd probably go with stainless steel for 
something with tiny BGA's,  but have done chip-scale IC packages with paper 
stencils.  It's only recently that small stainless steel stencils have become 
easily available and cheap.
---
Laser cut Kapton are fine for a few boards - up to 5 or so.  You start
seeing the effects of use after six or eight and steel is clearly a
value. . I use them for most protos. 

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

[Bob Camp]

Hi

A “low cost” auto pick and place does have some things in common with a 3D 
printer:

Drive is by stepper motors
Micro stepping stepper motor drivers are used
Belt drive is pretty common
Tube support and circular ball bearings are generally used
You have X, Y and Z drive
Very custom software to drive them that may or may not be open source
A setup and calibration process that may not be a lot of fun
A requirement to do some trial runs before you do anything important

There are generally a few things different between my 3D printer and a simple 
pick and place:

The drive is on both sides of the X / Y region
The X/Y is *much* larger than the Z
There is a Z rotation (4th axis) on the pick and place. 
My 3D printer has one head, two heads is about as low as they go on pick and 
place 
The parts feeders are a big part of the pick and place machine and there are a 
lot of them (even on a simple one). 
The base plate is a lot heavier duty (more rigid)
Vacuum to do the parts pickup
Pressure to blow off a stuck nozzle 
Some means to detect that a part has been picked up 
Interchangeable pick heads (the head size needs to match the part size to some 
degree)
A “small” (“desktop”) pick and place is a meter square. Most 3D printers are 
much smaller. 

— As you move up, the pick and place *might* have —

A camera to check parts on the placement head to properly align them (“up 
camera”) 
A camera to check the board and align to it (“down camera”)
Four or more placement heads.
Enough variety in feeder widths to match the size of the reels you have :)

No matter what you do for a pick and place, you will need:

Some way to mount the board on the machine 
Mounting holes (or whatever) on the board to match up with the machine
A design allowance that keeps parts out of the area contacted by the mounting 
setup
Fiducial marks to line things up that are of a type the machine can work with

There are lots of details….The 3D printer takes cad files and generates motion 
information.
The pick and place take the output of a PCB layout program and generates motion 
information.
It goes on and on ...

Bob










> On Jun 24, 2016, at 2:59 PM, Graham / KE9H  wrote:
> 
> Don Latham said
> to Discussion
> I do not see why a small pick and place assist system could not be built on
> a 3-d printer.
> 
> 
> Lots of problems to be solved...
> 
> How do you take loose parts or cut tape or tape reels and get the right
> part out, and into the chuck, oriented in the right direction?
> How many different kinds of parts, sizes, shapes, pin counts, IC
> footprints, can you handle at once?
> How do you know it is the correct part?
> How do you know where the "+" end, or "pin 1" is?
> How do you know that there actually is a part in the chuck?
> How do you know the part in the chuck is oriented the way you expected it?
> How do you know where the footprint on the circuit board is located? (to a
> few thousandths.)
> How do you know the part left the chuck and ended up where you intended it
> to be?
> 
> Commercial systems have answers to all of these questions. In many cases
> involving intelligent vision systems.
> 
> Once they are all answered, then you have a PCB unique set-up / programming
> effort to instruct the placement machine all about today's specific board
> and parts list to be assembled.
> 
> I can usually build one or two boards by hand about as fast as an engineer
> can do the placement machine specific PCB programming and verification.
> 
> --- Graham
> 
> ==
> 
> 
> 
> 
> 
> 
> On Fri, Jun 24, 2016 at 11:52 AM, Don Latham  wrote:
> 
>> I do not see why a small pick and place assist system could not be built
>> on a 3-d printer.
>> Don
>> 
>>> On Jun 24, 2016, at 8:32 AM, Attila Kinali  wrote:
>>> 
>>> On Thu, 23 Jun 2016 20:16:34 -0500
>>> Oz-in-DFW  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 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 

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

[David]

On Fri, 24 Jun 2016 20:01:24 +0100, you wrote:

>...
>
>I definitely concur with the 'make it SMT as much as possible' plan -
>pin-mount stuff is a pain. Also, QFN is far preferable to QFP, as
>catalogue suppliers don't always manage to ship fine-pitch stuff
>without bending legs in one direction or another. Reworking a duff QFP
>(or fine-pitch SOP) can take as long as assembling a whole board. With
>small volumes, there's no real statistical process control, you just
>do what you think will work, fix any defects, and update the big
>logbook of results.
>
>...

I keep wishing J-lead PLCCs were still available.  With them you had
the options of direct soldering their 0.050" lead spacing or using a
sockets with a pin spacing of 0.100".
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping

[Nick Sayer via time-nuts]

> On Jun 23, 2016, at 6:28 PM, Jay Grizzard  
> wrote:
> 
> On Thu, Jun 23, 2016 at 11:28:00PM +, Mark Sims wrote:
>> A usable re-flow oven can be had for $300.
> 
> Do you (or anyone) have suggestions for usable reflow ovens in this price
> range? 

I sell a reflow oven conversion kit on Tindie, FWIW.

https://www.tindie.com/products/nsayer/toast-r-reflow-power-board-kit/
https://www.tindie.com/products/nsayer/toast-r-reflow-controller/

It’s two separate pieces because I really wanted to divide the problem between 
the dangerous power handling bits, and all the rest, which is low voltage and 
safe to fool with. The intent is that you gut the toaster oven’s native 
controls and install the power board inside. You connect a 3 wire LV cable to 
the control port and bring that out to the controller. The control is 
opto-isolated triacs, so effectively an LED acts as a proxy for the elements.

I’ve been using them with the same toaster oven ever since the very beginning. 
The toaster isn’t agile enough for RoHS paste, but that could probably be fixed 
by better insulation or perhaps hacking in an extra heating element.
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

[Steve Wiseman]

On 24 June 2016 at 14:23, Attila Kinali  wrote:

> Unlike what most people seem to think, small batches of PCBs have always
> been a business for some assembly companies.

For my sins, I am one of those... (Cambridge, UK).
Yes - semi-manual assembly is the way it goes, especially for the
active parts. It's just not worth teaching the machines and loading
the parts for small runs. Typically, passives with more than 20
instances I'll load onto the machines, then do the rest by hand on a
manual placer.

Stencils - not any more. I use a dispensing robot, which is fine down
to 0.4mm pin pitch as long as the ambient temperature is right (35oC,
quite deeply unpleasant to share a room with). No more cleaning
stencils, throwing away paste, or wishing that the customer-supplied
stencil wasn't unhelpful in one of a thousand ways. It also means that
I can go from CAD data to built boards in less than a day, if I ply my
local PCB house with enough cash...

I definitely concur with the 'make it SMT as much as possible' plan -
pin-mount stuff is a pain. Also, QFN is far preferable to QFP, as
catalogue suppliers don't always manage to ship fine-pitch stuff
without bending legs in one direction or another. Reworking a duff QFP
(or fine-pitch SOP) can take as long as assembling a whole board. With
small volumes, there's no real statistical process control, you just
do what you think will work, fix any defects, and update the big
logbook of results.
Hacked reflow ovens have a place, but there are some parts that simply
won't solder with IR - the heat load to get the balls to melt is more
than it takes to kill the part. LTC's modules are especially bad, but
any BGA runs a risk. I'm a recent and thorough convert to vapour phase
(which can also be done in a homebrew manner).

Also - Please overbuy components!
those extra few 0402 resistors cost you a penny. Finding the one that
pinged off or the machine threw on the spitback pile - impossible.

Sorry about the offtopic. (I'm also a moderate frequency nut and EMC
chamber owner, so am starting to get nutty about RF amplitudes, which
is a whole new game...)

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

[Graham / KE9H]

Don Latham said
to Discussion
I do not see why a small pick and place assist system could not be built on
a 3-d printer.


Lots of problems to be solved...

How do you take loose parts or cut tape or tape reels and get the right
part out, and into the chuck, oriented in the right direction?
How many different kinds of parts, sizes, shapes, pin counts, IC
footprints, can you handle at once?
How do you know it is the correct part?
How do you know where the "+" end, or "pin 1" is?
How do you know that there actually is a part in the chuck?
How do you know the part in the chuck is oriented the way you expected it?
How do you know where the footprint on the circuit board is located? (to a
few thousandths.)
How do you know the part left the chuck and ended up where you intended it
to be?

Commercial systems have answers to all of these questions. In many cases
involving intelligent vision systems.

Once they are all answered, then you have a PCB unique set-up / programming
effort to instruct the placement machine all about today's specific board
and parts list to be assembled.

I can usually build one or two boards by hand about as fast as an engineer
can do the placement machine specific PCB programming and verification.

--- Graham

==






On Fri, Jun 24, 2016 at 11:52 AM, Don Latham  wrote:

> I do not see why a small pick and place assist system could not be built
> on a 3-d printer.
> Don
>
> > On Jun 24, 2016, at 8:32 AM, Attila Kinali  wrote:
> >
> > On Thu, 23 Jun 2016 20:16:34 -0500
> > Oz-in-DFW  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 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
> 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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> >
>
> Felix qui potuit rerum cognoscere causas.
> Lucky is he who has been able to understand the causes of things.
> Virgil
> ---
> "Noli sinere nothos te opprimere"
>
> Dr. Don Latham, AJ7LL
> Six Mile Systems LLC, 17850 Six Mile Road
> Huson, MT, 59846
> mailing address:  POBox 404
> Frenchtown MT 59834-0404
>
> VOX 406-626-4304
> CEL 406-241-5093
> Skype: buffler2
> www.lightningforensics.com 
> www.sixmilesystems.com 
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping

[John Ackermann N8UR]

You know, this thread has had a tremendous amount of practical information, 
with actual URLs, etc.  Would someone be willing to consolidate the info on a 
web page somewhere?

> On Jun 24, 2016, at 9:56 AM, Oz-in-DFW  wrote:
> 
> On 6/23/2016 10:53 PM, Chris Albertson wrote:
>>> Am I missing some obvious cheapie oven without these types of problems?
>> 
>> A lot of people are building them from Black and Decker (and the like)
>> toaster ovens.  Use Arduino for controller or just eyeballs. oven
>> thermometer and wrist watch.It is not rocket science the Arduino
>> controller software reads a thermocouple and controls an on/off relay.
>> Lots of instructions around if you google for reflow toaster oven.
> I'm using a
> PicoReflow.https://apollo.open-resource.org/mission:resources:picoreflow 
> It's Raspberry Pi based, so the board cost is about the same as an
> Arduino, but I use my tablet as the user interface AND tweaking profile
> is trivial unlike most of the Arduino based stuff. The system uses an
> internal web server and can be connected to a local monitor, or a web
> interface. All the control logic is in Python. I used the tablet browser
> and I don't need to stand next to it to monitor operation. This is
> particularly handy when I'm baking out parts.  I hand wired the
> interface board (trivial I/O) and used a purchase MAX31855 based board
> for another $20 from
> http://www.playingwithfusion.com/productview.php?pdid=19=1001
> (love the site name)
> 
> -- 
> mailto:o...@ozindfw.net
> Oz
> POB 93167 
> Southlake, TX 76092 (Near DFW Airport) 
> 
> 
> 
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

[Bob Camp]

Hi

If you are doing a board with a few hundred parts on it (as earlier mentioned). 
And have designed
a “3D printer” pick and place that runs one reel at a time. And are running the 
printer slow to keep
everything from going all over the place. And have a manual reel advance (no 
feeder) …. 

I can easily see you getting into a “put it away for today” situation. You can 
beat a simple system like that 
(speed wise) with a good manual vacuum pickup and some modest pre-organization 
of parts. 

Bob

> On Jun 24, 2016, at 9:45 AM, Oz-in-DFW  wrote:
> 
> On 6/23/2016 9:36 PM, Bob Camp wrote:
>> Hi
>> 
>> The gotcha with “really slow” is that once you print the solder paste on the 
>> board, it has a very 
>> limited “open air” life. If you don’t get the board done fairly quickly, 
>> your soldering quality can
>> suffer quite a bit.
>> 
>> Bob
>> 
> For most of the paste formulations I've had no trouble with several
> hours of working time. So you need to get at it, but really don't end up
> hurting yourself, but can't leave it overnight. .
> 
> -- 
> mailto:o...@ozindfw.net
> Oz
> POB 93167 
> Southlake, TX 76092 (Near DFW Airport) 
> 
> 
> 
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[time-nuts] Components placer review

[F Mitchell]

Interesting product.

Mitch W4OA

https://www.elektormagazine.com/news/review-ec-placer-makes-placing-smd-components-a-piece-of-cake
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

[Oz-in-DFW]

On 6/24/2016 8:23 AM, Attila Kinali wrote:
> On Thu, 23 Jun 2016 19:28:15 + (UTC)
> Bob Stewart  wrote:
Lotsa stuff deleted
>> One more related question before this topic dies, if you don't mind.
>> What about the other side of building: stuffing the boards.  My GPSDOs
>> have about 120 parts per board, plus some custom work on the SMA connectors.
>> Is there a service out there that will populate boards with SMT components
>> for small orders at a reasonable price?  Small is 10 boards.
>  The advantage of "professional"
> companies like Alktech over "hobbyist" companies like macrofab is,
> that you get full professional support while the price does not differ much.
> E.g. while macrofab only does 4 layer boards if you specially ask for it,
> for Alktech getting any number of layers is standard procedure.
>
>   Attila Kinali
>
Just to correct a misunderstanding. Macrofab, Small Batch Assembly, and
PCB:NG are all professionals, not hobbyist companies. they focus on
small runs at low cost, but they are manufacturing professionals with
commensurate results.


-- 
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Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 



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

[Oz-in-DFW]

On 6/24/2016 9:32 AM, Attila Kinali wrote:
> On Thu, 23 Jun 2016 20:16:34 -0500
> Oz-in-DFW  wrote:
>> 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
>
Laser cut Kapton are fine for a few boards - up to 5 or so.  You start
seeing the effects of use after six or eight and steel is clearly a
value. . I use them for most protos. 

If I'm doing anything really fine that would drive me to steel on
resolution alone, I pay someone else to do it.

Oshstencils are cheap, and they will do 4 mill Stainless Steel for 2X
Kapton cost.  Deal if I'm doing more than 5 boards.


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Oz
POB 93167 
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

[Brooke Clarke]

Hi:

For IC pitches of 0.050" (1.27mm) hand soldering works fine, even for my vision 
when a stereo microscope is used.
Elmer's glue to hold the chips is place.

Getting boards from ExpressPCB that have solder mask helps to prevent bridging.

Here is an example:
http://www.prc68.com/I/BTSG.shtml

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.


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

[Don Latham]

I do not see why a small pick and place assist system could not be built on a 
3-d printer.
Don

> On Jun 24, 2016, at 8:32 AM, Attila Kinali  wrote:
> 
> On Thu, 23 Jun 2016 20:16:34 -0500
> Oz-in-DFW  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 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 
> 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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> 

Felix qui potuit rerum cognoscere causas.
Lucky is he who has been able to understand the causes of things.
Virgil
---
"Noli sinere nothos te opprimere"

Dr. Don Latham, AJ7LL
Six Mile Systems LLC, 17850 Six Mile Road
Huson, MT, 59846
mailing address:  POBox 404
Frenchtown MT 59834-0404

VOX 406-626-4304
CEL 406-241-5093
Skype: buffler2
www.lightningforensics.com 
www.sixmilesystems.com 
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

[Attila Kinali]

On Thu, 23 Jun 2016 20:16:34 -0500
Oz-in-DFW  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 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 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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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping board

[Oz-in-DFW]

On 6/23/2016 9:36 PM, Bob Camp wrote:
> Hi
>
> The gotcha with “really slow” is that once you print the solder paste on the 
> board, it has a very 
> limited “open air” life. If you don’t get the board done fairly quickly, your 
> soldering quality can
> suffer quite a bit.
>
> Bob
>
For most of the paste formulations I've had no trouble with several
hours of working time. So you need to get at it, but really don't end up
hurting yourself, but can't leave it overnight. .

-- 
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Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 



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

[Oz-in-DFW]

On 6/23/2016 10:53 PM, Chris Albertson wrote:
>> Am I missing some obvious cheapie oven without these types of problems?
>
> A lot of people are building them from Black and Decker (and the like)
> toaster ovens.  Use Arduino for controller or just eyeballs. oven
> thermometer and wrist watch.It is not rocket science the Arduino
> controller software reads a thermocouple and controls an on/off relay.
> Lots of instructions around if you google for reflow toaster oven.
I'm using a
PicoReflow.https://apollo.open-resource.org/mission:resources:picoreflow 
It's Raspberry Pi based, so the board cost is about the same as an
Arduino, but I use my tablet as the user interface AND tweaking profile
is trivial unlike most of the Arduino based stuff. The system uses an
internal web server and can be connected to a local monitor, or a web
interface. All the control logic is in Python. I used the tablet browser
and I don't need to stand next to it to monitor operation. This is
particularly handy when I'm baking out parts.  I hand wired the
interface board (trivial I/O) and used a purchase MAX31855 based board
for another $20 from
http://www.playingwithfusion.com/productview.php?pdid=19=1001
(love the site name)

-- 
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Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 



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

[Attila Kinali]

On Thu, 23 Jun 2016 19:28:15 + (UTC)
Bob Stewart  wrote:

> One more related question before this topic dies, if you don't mind.
> What about the other side of building: stuffing the boards.  My GPSDOs
> have about 120 parts per board, plus some custom work on the SMA connectors.
> Is there a service out there that will populate boards with SMT components
> for small orders at a reasonable price?  Small is 10 boards.

Unlike what most people seem to think, small batches of PCBs have always
been a business for some assembly companies. I know a couple of those
in Europe that are specialized in small volumes (<100pcs per batch) and
reject anything larger. If you google for "PCB prototype assembly" you should
find some in your area. The more electronic industry you have in your area,
the more you will find those assembly fabs. Especially if your electronic
industry consists of mostly small, specialized companies. There are also
some inter-regional companies specialized on hobbyist market, like macrofab.

The prices vary a bit, depending on where you live, but usually
using 2*(BOM cost) and/or (BOM Cost)+300 are good estimates for
how much it will cost to build a PCB. "Going east" might also be
a good strategy. I know one fab in Estonia (Alktech www.alktech.com)
that does offer pretty competitive prices, while giving better quality
than what you usually get from china. The advantage of "professional"
companies like Alktech over "hobbyist" companies like macrofab is,
that you get full professional support while the price does not differ much.
E.g. while macrofab only does 4 layer boards if you specially ask for it,
for Alktech getting any number of layers is standard procedure.

If you want to keep prices low, then the first thing you should do is
to minimize your BOM: The fewer different parts you need, the better.
Ie if you have 200R, 100R and 50R resistors in your design, replace the
200R and the 50R by series and parallel connected 100R resistor. The cost
of a single resistor (transistor, chip, ...) is usually much lower than
having to handle another reel/tray. Especially if the fab has to go onto
the bigger pick machine because the number of feeders needed didn't
fit on the small machine.

The second cost saving thing is to minimize through hole components. Use
SMD as much as you can. It doesn't cost much to place an SMD component.
After the pick and place (which can be manual work on small volumes) the
soldering is done in an oven. But soldering a THD part means that someone
has to solder it by hand, as it would be too expensive to perpare a machine
for this. You can take this even further to let the fab only populate the
SMD parts and populate the THD parts yourself, which then only costs a bit
of time. (In my experience, THD solder jobs vary quite a lot more in quality
than one would expect. So doing it yourself might even improve quality).


The last way to minimize cost is to use common components and give the
fab the freedom to choose replacement parts. This gives the fab the
opportunity to choose parts that they already have on stock or buy
in large volumes, which makes them a lot cheaper. But means that you
specify the parts such that they are only as restrictive as you need.
I.e. if most of your reistors can be 5%, then specify them as 5% and
not as 1%. Even odd percent numbers are ok, though usually frowned upon,
as the company will choose the next better rating they have on stock.

Oh: and one additional hint: do not get the PCBs yourself. Let the fab
buy them. Then they will be panelized in the way they like it the best.
There is of course a little price hit if they buy it, but it usually pays
off when taking NRE costs into account.

As for doing assembly yourself: Yes it's possible and a good way to save
money. But be prepared to experiment a lot until you get consistent
and good results. Unless you have some serious experience in machine
soldering you will need a couple of runs in the beginning to figure
out how to do it right. And some things only show after a couple of
months/years after soldering (like borderline cold solders, cracks,
whiskers, popcorn packages etc) that depend on the quality of solder
and settings of the solder process. Also, IR solder ovens do not work
well with anything that casts a shadow on the solder joint, like QFN
or BGA parts.. or even high parts (alu capacitors or connectors)
next to low parts (IC's, resistors). That's the main reason why industry
pretty much stopped using (pure) IR ovens for production and switched
to convection type and vapor phase ovens. 

An alterantive to the ubiquitous IR ovens are rework-heater plates. 
These are basically just electrical stoves with temperature control
and a PCB holder ontop. They are ment as helpers for reworking, when
large ground planes confound any attempt of using a soldering iron.
By heating up the PCB to 50-100°C it is easy to get the last few
degrees with an iron. These heating plates can go 

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

[Dave M]

Take a look at the oven at http://whizoo.com/buy . They sell several kits as 
well as a complete kit to modify a toaster oven, and a ready-to-go oven for 
$699, shipping included.  According to the web site, it uses a B model 
T01303SB toaster oven, capable of handling an 8"x10.5" board.
The oven and controller, as shipped, is calibrated for lead-free solder, but 
if requested, he can recalibrate for any solder paste, so long as you 
provide the manufacturer's reflow requirements.

The controller firmware is open source.

ControLeo2 specifications and features
 a.. ATmega32u4 microcontroller with Arduino Leonardo boot loader
   a.. 32Kb Flash memory
   b.. 2.5Kb SRAM
   c.. 1Kb EEPROM
 b.. LCD display - 2 lines x 16 characters.
 c.. 4 relay outputs - relays are connected using screw terminals or the 
6-pin relay header (4 outputs, +5V, GND). The outputs provide up to 220mA at 
5V. The outputs support connections to solid-state relays (SSRs) or 
mechanical relays

 d.. Buzzer - 80db at 10cm
 e.. 2 momentary switches - for user input.
 f.. ABS plastic case - custom fit, flame-retardant (UL94-5VA)
 g.. MAX31855KASA thermocouple - capable of reading temperatures 
from -200°C to 1350°C using a k-type thermocouple.
 h.. Input voltage: 5V (USB or screw terminals) - For reliability and 
longevity, the screw terminals should be used to power ControLeo2. For 
solid-state relays, the 500mA provided by USB is sufficient to power 
ControLeo2 and the relays. For mechanical relays please use a 1000mA 5V 
power supply connected to the screw terminals.

 i.. Pre-loaded software - Reflow Wizard
Looks like a pretty decent project.  I've no connection with the seller... I 
found this project after getting intrested in this thread.


Cheers,
Dave M


Chris Albertson wrote:

Am I missing some obvious cheapie oven without these types of
problems?



A lot of people are building them from Black and Decker (and the like)
toaster ovens.  Use Arduino for controller or just eyeballs. oven
thermometer and wrist watch.It is not rocket science the Arduino
controller software reads a thermocouple and controls an on/off relay.
Lots of instructions around if you google for reflow toaster oven.

As for pick and place, the old method still works.  Work by hand under
a low power stereo microscope.  You buy a syringe of solder past and
place little dabs on each pad then place the part with twitters.
Many years ago I worked at a place that had a few dozen women who did
this all day long.   You can get a very good used microscope (5x to
20x zoom works well) for under $250 and a workable one for under $100.
But many people today are using cameras and a big computer monitor in
place of the microscope.



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

[Dan Kemppainen]

I’ve been doing SMT assembly for 40 years. I have never ever seen anybody with 
a process
that “just worked”. They all involve some amount of fine tuning and design 
optimization.



Hi,

Yep, The amount of tweaking required to get a good board build can be 
extensive. Part density, ground plane, part sizes, solder type, solder 
age, stencil design, board finish, and SMT pad design all add up. Tweaks 
in the oven and stencil can be required to make it work.

It's the tweaking it that can get expensive fast...

Dan


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

[Oz-in-DFW]

Disclaimer:  I've not used any of these yet.  New style assembly houses
are MUCH cheaper than traditional proto shops.  The ones I'm planning on
trying are:

Macrofab (Houston)  https://macrofab.com/

pcb:ng http://pcb.ng/index.html (currently in beta with **deep**
discounts.   $1/sq in + BoM cost

Small Batch Assembly  http://www.smallbatchassembly.com/

All of these guys have their advocates. All will do under 10 pcs.I
plan on running a similar job through each of them and seeing what I find.

On 6/23/2016 2:28 PM, Bob Stewart wrote:
> One more related question before this topic dies, if you don't mind.  What 
> about the other side of building: stuffing the boards.  My GPSDOs have about 
> 120 parts per board, plus some custom work on the SMA connectors.  Is there a 
> service out there that will populate boards with SMT components for small 
> orders at a reasonable price?  Small is 10 boards.
>
> Bob - AE6RV
>
>


-- 
mailto:o...@ozindfw.net
Oz
POB 93167 
Southlake, TX 76092 (Near DFW Airport) 



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[time-nuts] Trimble / Symmetricom UCCM mini-GPSDO boards

[Mark Sims]

For those of you that have one of these... good-ish news.   I have Lady Heather 
working with them (well, at least the Trimble works,  the Symmetricoms have not 
arrived yet and there are a couple of known differences in their commands).  
I'll get the code out there when I have a chance to test it with the 
Symmetricoms.  They seem to fairly nice little units.  Not as tweakable / 
versatile as a Z3801A, etc but quite usable.

For those that are thinking about buying one,  be aware that there are some 
pretty skeezy / clueless / dishonest sellers out there.  People have received 
units with various parts that have been physically damaged or ripped off the 
boards.  Apparently one or more of the Chinese scrappers was less than gentle 
removing them from whatever it was that they came out of.  EEVBLOG has a long 
thread that mentions the Chinese Standard GPSDO Damage Infliction.  A couple of 
devices (an inductor, a couple of caps, and some connectors) seem to be the 
most prone to be damaged... most damage was easily repaired.   My Trimble came 
from a seller with a high reported coefficient of skeezyness, but was in 
perfect condition.  Oh, and they run on 6V 2A startup,  .8A warmed up.  

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

[Bob Stewart]

I've given thought to stencils, but without building something to prop my hands 
on, I'll smear the paste.  So, I place up to 10 or 15 parts at a time and use 
the hot-air gun.  To each his own, I guess.

Bob

---
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info


On Thu, 6/23/16, Oz-in-DFW  wrote:

 Subject: Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping 
board
 To: "Discussion of precise time and frequency measurement" 
 Date: Thursday, June 23, 2016, 8:16 PM
 
 I'll second this, and
 suggest you consider:
 
  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.
  3. You can only place a limited list of parts
 for a run.  If you have
     one more part
 than the machine will accomodate, its a second (or
     third, or fourth pass.)
 
 4. They are all high maintenance in addition to requiring
 tuning. A lot
     of the maintenance is
 based on calendar, not operation time.  Even
     and idle machine requires time if you
 actually want to use it
     eventually.
  5. Most are closed software loops. You work
 around their poor (or un)
     documented
 formats and bugs.
  6. There are really cheap
 small batch assembly houses coming online
  
   that will do under 10 units. See Macrofab, PC:NG, Small
 Batch
     Assembly are fairly quick
 turns.
 
 If all you are doing
 is protos, hand placement, mylar solder stencils
 (see Oshstencils and others) and a hacked
 toaster oven are a good
 solution. The $500
 Chinese reflow ovens seem to require more (re)work
 that a $50 toaster oven.  If you use stencils
 to place the solder, part
 placement is as
 fast (or faster) than through hole parts. I have to use
 a microscope.  I'm shaky enough that  may
 need to built some Waldoes
 soon.  ;-)
 
 I just did six moderately
 complex boards (no fine pitch parts) and that
 was 2-3 too many for me.
 
 Solder stencils make **all** the difference.
 
 Oz, in DFW
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping

[Hal Murray]

kb...@n1k.org said:
> I’ve been doing SMT assembly for 40 years. I have never ever seen anybody
> with a process  that “just worked”. They all involve some amount of fine
> tuning and design optimization. 

As an example...  I remember supplying dead chips to the fab house so they 
could calibrate their setup without using real chips.  The context was large 
ceramic BGAs.  We were an early customer.  Working chips were scarce.  
Everybody involved seemed to know about that trick.

-- 
These are my opinions.  I hate spam.



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