Searching \ for '[OT] Going with SMT' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/pcbs.htm?key=smt
Search entire site for: 'Going with SMT'.

Exact match. Not showing close matches.
PICList Thread
'[OT] Going with SMT'
2006\01\09@193000 by Rolf

face picon face
Hi all.

I am contemplating SMT components for my current project. I have it all
wired up right now on a breadboard with through-hole parts, but the
compactness of SMT is appealing.

I am a novice to much of the hobby. This would be my second project to
make it to the "production" stage... the first was done in a
sea-of-holes fashion.

My intention with this project is to etch my own board as well...

So, given that I have some small successful hobby projects behind me,
and that I am interested in persuing many more projects, I figure it is
time to get more "professional" and compact in my execution.

In order to go ahead with the SMT process though, I will have to
re-stock all the components I have with SMT equivalents, and a I will
have to manually solder them to a home-brewed PCB.

Is this something that is feasable with limited resources/budget?

There are some things I will have to do through-hole as well (sockets
and connectors).... but other than that I am looking at a dozen
resistors, a dozen capacitors ranging from 22pF through 100uF, MAX232A,
a few diodes, a LM7805 (SMT equivalent), Quad Optocoupler, one FET, a
few LED's, A 16Pin header to an LCD Module, an external power socket,
and an RS232 9Pin D-Sub. Oh, and a PIC18F4320.

It will probably take me a month to decide what parts to use, to do a
few trial runs of PCB Etching (Double sided), to make the schematic and
PCB Layout, and to get the parts on hand. I need to know whether it
would be possible to do so with the same equipment that would be used
for pure through-hole projects. Would I need any special tools?

Is this something that is within reach of a beginner-to-intermediate
hobbyist?

Thanks in advance for any insights, criticisms, suggestions.

Any links to dealing with SMT components would be appreciated too.

Rolf

2006\01\09@193841 by David VanHorn

picon face
>
>
> In order to go ahead with the SMT process though, I will have to
> re-stock all the components I have with SMT equivalents, and a I will
> have to manually solder them to a home-brewed PCB.
>
> Is this something that is feasable with limited resources/budget?


Sure.
1206 is a lot easier to work with than 0201 for discretes, but in general,
yes.

A good iron is a must. A baby metcal from ebay is a nice investment.
Good magnification is another must. A 10x stereo microscope is pretty much
ideal.
Light is a must too, but that's easier to deal with.

You'll be surprised at the end of the assembly, how much mess you DONT have
to clean up!

You can DO 1206 parts with a 40W weller iron, and naked eye, but unless
you're younger than me, it might not be all that pleasant.

2006\01\09@200809 by Marcel duchamp

picon face
Rolf wrote:
> Hi all.
>
> I am contemplating SMT components for my current project. I have it all
> wired up right now on a breadboard with through-hole parts, but the
> compactness of SMT is appealing.
>
>
> Is this something that is feasable with limited resources/budget?
>
> Is this something that is within reach of a beginner-to-intermediate
> hobbyist?

If you already have a good soldering iron (and eyeballs) then it's
easier.  We routinely do 0603 and larger with 40Watt Wellers here. For
me and other "senior" folks, a head-mounted magnifier is
handy^H^H^H^H^H^H required.

For doing your own PCB's at home, smd's require fewer holes - unless you
are going for extreme density and end up with lots of vias.

If you have need for any 1% resistors, do yourself a favor and just make
 all your resistors 1%.  There is no real price difference and then you
don't need to wonder "is this a 5% 10K or a 1% 10.0K part?".

For IC's, if you can stick to .050" lead pitch or larger, you will do fine.

> Is this something that is within reach of a beginner-to-intermediate
> hobbyist?

The world seems to be going that way; the sooner you learn smd's, the
better if you are going to make this your career.

Good luck!

2006\01\09@201304 by Jinx

face picon face
> Is this something that is within reach of a beginner-to-intermediate
> hobbyist?

Hi Rolf, sure, I do a bit of SMT at home. It's not too hard.
Sometimes you have to use SMT because that's the only easily-
obtainable package for some components (PIC 10F for example,
in NZ, large SRAMs, specialty components etc)

Where you can makes things easier for yourself is getting the
right tools. Magnifier, lamp, various tweezers, a fine-tipped
iron and small gauge solder + wick. A comfortable working
position helps a lot too

> Any links to dealing with SMT components would be appreciated
> too

In NZ I use Surface Mount Devices for many general components

http://www.smd.net.nz/

Very reasonably priced. I'm sure you could find a company like
this in your area. I'd advise not starting with 0402 packages. They
are usable but 0804 or 0603 are easier to work with. The numbers
refer to 100ths of an inch, so 0402 is 0.04" x 0.02". That's tiny.
Unless you really really need to save space it's not worth the strain

2006\01\09@204125 by Sergey Dryga
face picon face
Rolf <learr <at> rogers.com> writes:

> My intention with this project is to etch my own board as well...
I have good success with presensitized 2-sided boards from Datak (bught at
Jameco).  You can print the artwork on an ink-jet printer transparency.  
Exposure frame helps a lot.  Heat-transfer film did not work as well for me.

> Would I need any special tools?
Hot-air rework station and vacuum pick-up tools are nice, but cost a lot (it
is on my Cristmas wish list).  In the mean time, I use RadioShack 15W iron
(please people, do not laugh so hard!).  It has very nice tip and just right
power/temperature.  Also, buy some tinning (Tin-it from Datak) solution for
PCB, it would be easier to solder.  I also use solder paste (Radioshak and
many other places) instead of rosin-core solder.  In this case all you need is
to just heat up the pad after placing the part.

And, like other people suggested: get a good light, magnifier, forceps and
fine desoldering wick.
>
> Is this something that is within reach of a beginner-to-intermediate
> hobbyist?
>
Absolutly!

> Thanks in advance for any insights, criticisms, suggestions.
>
> Any links to dealing with SMT components would be appreciated too.
>
Somebody posted a guideline for PCB design on this list, probably last week.

Good luck,
Sergey

2006\01\09@212034 by Jinx

face picon face
> You can DO 1206 parts with a 40W weller iron, and naked eye,
> but unless you're younger than me, it might not be all that pleasant

No, isn't. You can do a few unaided but after that.........

Rolf, this works for me

To put down a cap or resistor, and put it down flat, I'll tin one
pad first. Then place the component with the tweezers. Reheat
the tinned pad so that the component lead becomes soldered.
Whilst the solder is molten, gently push down on and adjust the
part so that it lays straight and  flat. When the soldered end has
cooled, do the other. Don't apply too much heat or the whole lot
will just come adrift from the board and end up stuck on the tip

For ICs, tin one corner pad, align/solder/cool as above, then do
the opposite corner

It'll never look as clean and tidy as a manufactured item, but to
stand back and look at what you just did, and think, "Damn, I'm
a big boy". Can't beat it for satisfaction

Until you have to do another one ;-))

2006\01\09@214904 by Jesse Lackey

flavicon
face
I concur with the soldering method below, but add a step: after doing
the 2nd end of the resistor/cap, reflow the first, adding a tiny bit
more solder so the joint is "fresher".  It might not be necessary but I
don't like the idea of reheated solder being used as the first
connection to the part.  I've done 1000s of parts this way, no failures.

Also I suggest:
1. getting a temperature-controlled iron

2. using 0805 or 0603 parts.  Everything I do is 0603, if available in
that size.  0402 is kind of ridiculous to use for things hand-assembled.

3. don't etch your own boards.  I did this for awhile long ago, and its
just hassles and troubles, there is always the open or shorted trace or
three on anything reasonably complex.  Even using a modified laminator
to put the laserprinted resist pattern on the copper board - still not
really reliable.  (want to buy the laminator cheap??)  barebonespcb.com
is the way to go, unless on a tight budget and have more time than money.

4. get some flux cleaner and spray the board when done:
http://www.circuitspecialists.com/prod.itml/icOid/1689

Also, a friend just switched to SMT and barebonespcb - he put some SMT
soldering videos up, might be useful:
http://www.electric-clothing.com/superpov.html

Hope it helps!
J


Jinx wrote:
{Quote hidden}

2006\01\09@220608 by John Nall

picon face
Jesse Lackey wrote:
> > Also I suggest:
> 1. getting a temperature-controlled iron
>  
I've been reading  this  thread with interest, but with nothing to
contribute (since I have no experience with SMT).  But I am getting
ready to buy a new soldering iron, because mine dates to about
1980-something.  Most of the stuff that I do these days with it is very
small (primarily because that is the name of the game these days, I
guess).  Does anyone have any recommendation?  (I have a heavy duty
Weller for the big stuff, such as new SO-239 connectors, so am only
talking about a new iron for the small stuff).  There seems to be quite
a few different irons available.  What would you get if you were getting
a new one?  (While I would not go so far as to say that price is no
object, I usually figure that you get what you pay for, so try to get
good stuff even if it costs more, since it costs less in the long run.  
IMHO.).

2006\01\09@223036 by Xiaofan Chen

face picon face
Hakko 936 Soldering Station is the standard in my company and
it is good up to 0402 or even smaller. I think Weller got similar models.
If you go to Fry's there are both.

www.computronics.com.au/hakko/soldering/
http://www.hakkousa.com/ (a mess as I am under FreeBSD now with FireFox).

Regards,
Xiaofan

2006\01\09@223540 by Marc Nicholas

picon face
I cannot tell you the difference buying a "knock-off" digitally temp
controlled iron made for me over a hobbyist iron.

Next purchase is a "knock-off" hot air rework station...which I'm sure will
make the whole affair even easier.

-marc

On 1/9/06, John Nall <spam_OUTjwnallTakeThisOuTspamgmail.com> wrote:
{Quote hidden}

> -

2006\01\09@223651 by Spehro Pefhany

picon face
At 10:06 PM 1/9/2006 -0500, you wrote:
>   What would you get if you were getting
>a new one?  (While I would not go so far as to say that price is no
>object, I usually figure that you get what you pay for, so try to get
>good stuff even if it costs more, since it costs less in the long run.
>IMHO.).

A little pricey, but you can't go too far wrong with a Metcal MX-500DS-11.
(it needs shop air for desoldering) They seem to have recently chopped the
price by about 1/3 for some reason.

http://64.82.109.235/cgi-bin/scripts/product/5635-0087

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
.....speffKILLspamspam@spam@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
->> Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff


2006\01\09@232355 by James Humes

picon face
Not to disagree with the "more is more" philosophy, but I have done a lot of
small surface mount work with this cheap hot air station

www.sparkfun.com/commerce/product_info.php?products_id=76&osCsid=9288923d11c512b7ac65869359da14d0
#

including putting on a 28 pin QFN, although I don't recommend that at
first:)

James

2006\01\10@001413 by Xiaofan Chen

face picon face
On 1/10/06, James Humes <james.humesspamKILLspamgmail.com> wrote:
> Not to disagree with the "more is more" philosophy, but I have done a lot of
> small surface mount work with this cheap hot air station
>
> www.sparkfun.com/commerce/product_info.php?products_id=76&osCsid=9288923d11c512b7ac65869359da14d0
> #
>
> including putting on a 28 pin QFN, although I don't recommend that at
> first:)
>
> James

Hi James,

This one looks quite like the Hakko 905 we have but with a much cheaper
price tag. And out Hakko 905 died and the reparing cost is high. Interestingly
one of the main use for the Hakko 905 is to solder QFNs.

Maybe I can ask my boss to buy this cheap guy to have a try.

How do you like it so far?

Regards,
Xiaofan

2006\01\10@034649 by Juan Cubillo

flavicon
face
Hello list.

I also decided to start using smt components. (they look so good once soldered...)
I already bought many resistors, caps, diodes, leds, transistos, etc on ebay. I also bought a solder sucker that can be modified to solder smd devices using hot air...
Just make a google search for "hot air soldering diy".
Also,  make sure you can make  your own pcb. There is almost no way to use smd components on normal soldeirng boards with .1" holes.

Juan cubillo

{Original Message removed}

2006\01\10@043017 by Alan B. Pearce

face picon face
>> Would I need any special tools?
>Hot-air rework station and vacuum pick-up tools are nice,
>but cost a lot (it is on my Cristmas wish list).

A hotair rework unit is almost essential for doing any component removal.
For two leaded components like resistors, caps and diodes a soldering iron
that has two heated tips is ideal, but pretty well anything else needs hot
air. Someone did post a link here some time back on modifying a cheap radio
Shack desoldering tool into a hot air blower, but a quick scan of my saved
links doesn't find it.

I did find this link members.lycos.nl/anthonyvh/index.php?page=smd
which was described as a tutorial about soldering SMD devices with a normal
iron. haven't checked if the page is still up though.

Also in the essential tools, I would recommend a head mounted magnifier such
as an Optivisor or similar, tweezers, - especially the sort with the
crossover tips that are normally closed, which will save much cursing as
components are much less likely to go flying than the normally open sort,
and they are invaluable for removing components when heating with a hot air
gun. Get a reel of the finest solder you can find, and some nice fine tips
for your soldering iron, although people such as the Seattle Robotics group
have a web page where they talk of using a largish tip (Russells influence
is catching ;)) with lots of solder and wiping across multi pin ICs to
solder the pins. Some solder wick helps clean up.

Another item - make sure you have a well lit area to work in. I think this
is one aspect where you almost cannot have a too bright working area. It
does need to be evenly lit, rather than spot lit though.

Essentially all you need is some practice. If you can get a PCB, such as one
out of an old video recorder or similar item with SMD components, and play
with soldering and removing them, you will find that it isn't too bad at
all.

2006\01\10@071603 by Joe McCauley

picon face
This looks good at the price. What kind of iron tips does the iron use? Does
it have a voltage selector switch for 230 volt operation?

Joe

> {Original Message removed}

2006\01\10@082342 by Rolf

face picon face
Rolf wrote:
> Hi all.
> [snip ....]
>
> Thanks in advance for any insights, criticisms, suggestions.
>
> Any links to dealing with SMT components would be appreciated too.
>
> Rolf
>  
Thanks all for the huge response. It seems that I can, at least for the
first few boards, forge ahead with SM Components. I think then that I
have what I need for the immediate future (apart from the actual
components), and I can get by with my existing soldering iron, and desk
magnifier. Those N/C Tweezers sound like a good practical, and cheap
investment. I am reluctant to spend too much money before I have tried
it a few ways with what I already have first, as I would then be able to
prioritize my "investment strategy" more efficiently. Based on the
responses so far, it seems I am going to be lucky enough to be able to
spend nothing immediately, and, depending on how I do, I can consider a
purpose-designed soldering/Hot-Air system. I may put a logic analyzer on
the wish-list first though.

Regardless, I am still very interested in reading more responses, I just
wanted to acknowledge the responses so far.


On a (very) slightly different note.... Solder paste, I have not used it
before, so I would like to understand how it works better.

Looking at digikey part KE1507-ND
<http://ca.digikey.com/scripts/dksearch/dksus.dll?Detail?Ref=64134&Row=436224&Site=CA>
. Kester Solder Paste - NO CLEAN 63/37 35GM at $53Canadian.

Am I correct with the understanding that:
1. One simply applies it to each of the pads
2. It is tacky, so the SM Part will "stick" to it.
3. You can "touch" each pin with the soldering iron (or with Hot Air if
you have the tool).
4. Get next part....
5. Go to 1.

This seems to be fairly easy to manage, and relatively "clean". At $53
it is on the border-line of an investment, but it may well be worth it...

The instructions for it indicate that it should be stored in the fridge.

Thus, I am concerned that it may be overkill, yet at the same time, it
may be a great way to do things....
... but, it also may "go off" long before I could use even a fraction of
the tube. I imagine that If I solder a square-foot of board this year I
will have done a lot...

Maybe I should just stick with regular solder.

Thanks for any comments.

Rolf

2006\01\10@084926 by Brian Clewer

flavicon
face
Rolf wrote (regarding the solder paste):

> Am I correct with the understanding that:
> 1. One simply applies it to each of the pads

Yes - and NO.  You can apply the paste to each of the pads
but this is not as easy as you might think.  The proper way
to do this is to get a stainless steel shim made up with the
pads on the pcb cut out on the shim.  You simply then put the
paste on the top of the shim and spatula the paste over the
top with the PCB underneath. - A stencil.

> 2. It is tacky, so the SM Part will "stick" to it.

Yep.

> 3. You can "touch" each pin with the soldering iron (or with Hot Air if
> you have the tool).

Yes, but once the solder melts, the component has less sticking
ability to the board, so if you use an air gun, careful you
do not blow everything off the board.

> 4. Get next part....
> 5. Go to 1.

Another problem with the paste is that it has a use by date
because it dries out.  If you are buying a $50 tub, you
probably will not use 1/4 of it before it is unusable.

You should be able to buy it in smaller syringes.

2006\01\10@091716 by James Humes

picon face
Xiaofan,

   I have no complaints about the cheaper hot air station.  We also have a
nice weller hot air station, but I've had just as much luck using using the
hakko knock off from sparkfun.

James


On 1/9/06, Xiaofan Chen <.....xiaofancKILLspamspam.....gmail.com> wrote:
{Quote hidden}

> -

2006\01\10@100706 by Philip Pemberton

face picon face
In message <012701c6158c$74f536f0$0100a8c0@ivp2000>
         Jinx <joecolquittspamspam_OUTclear.net.nz> wrote:

> For ICs, tin one corner pad, align/solder/cool as above, then do
> the opposite corner

I've done TSSOPs like this:
 1) Place the part roughly in position and put some "Blue-tak" on the sides
of the IC casing (not where the pins are!) to hold it in place.
 2) Gently tweak the alignment of the chip until it's aligned *perfectly*.
 3) Solder two diagonally opposite pins down. Check the alignment again,
reheat and tweak if necessary.
 4) Soak the pins and the board in flux.
 5) Put a blob of solder on the tip of the iron
 6) Run the soldering iron over the pins. Watch as 20 pins get soldered down
in three seconds.
 7) Get a magnifying glass out and look for short circuits. Remove them with
desolder wick - don't worry too much about resoldering pins. Those tiny pins
tend to make it difficult to completely remove all the solder - generally
speaking, enough is left over to keep the pins stuck down.
 8) Now poke the pins with a multimeter probe or similar sharp object.
Reheat any that move.
 9) (optional) Put some isopropyl on the board and scrub the flux off with
an old toothbrush.

 This is how I've been doing it for the best part of a year - I've soldered
a good half dozen TSSOPs and a few SSOPs this way, and have (thus far) only
killed one IC.

 I still solder SOICs like DIPs - solder two diagonally opposite pins to
hold it down, then solder the rest of the pins individually.

 Also, never underestimate the usefullness of Blue-tak. It's great for
holding down SMD chips while soldering them. IIRC I picked up the trick from
a site that sold the STV5730A video chips...

 Anyone feel like sharing their soldering tips, or do y'all consider them
trade secrets? :)

Thanks.
--
Phil.                              | Acorn RiscPC600 SA220 64MB+6GB 100baseT
@spam@philpemKILLspamspamdsl.pipex.com              | Athlon64 3200+ A8VDeluxe R2 512MB+100GB
http://www.philpem.me.uk/          | Panasonic CF-25 Mk.2 Toughbook
... Make a decision based solely on money, you've made a bad decision.

2006\01\10@103719 by Marcel Duchamp

picon face
Rolf wrote:
>
> On a (very) slightly different note.... Solder paste, I have not used it
> before, so I would like to understand how it works better.
>
> Looking at digikey part KE1507-ND
> <http://ca.digikey.com/scripts/dksearch/dksus.dll?Detail?Ref=64134&Row=436224&Site=CA>
> . Kester Solder Paste - NO CLEAN 63/37 35GM at $53Canadian.

We use Kester paste with water soluble flux.  After soldering, hot water
washes the flux off - works very well.  But Digikey wants about US$42.
Future has it for US$14; search distributors listed on Kesters site.

Yes, it needs to be stored cold.  We buy 10 tubes at once and store them
in the freezer.  When one is brought out, we just leave it on the bench.
 I date the tubes as I open them; they last around 2 months before the
paste is too thick to squeeze out.  New tube of paste will flow with the
slightest thumb pressure on the syringe plunger; dry paste will not flow
at all.

We also bought a bag of 100 syringe tips from McMaster-Carr - about a
nickel each.

BTW, wash the flux off before reworking with rosin flux.  Otherwise the
two different fluxes will mix making a difficult to remove gummy mess.

The hot air method works but does tend to blow parts around. The "easy
bake" method works well.   A toaster-oven is used.  We have one with
elements above and below.  Preheat the oven at 250F for 10 minutes
minimum.  Put boards in with paste and parts.  Heat for 1.5 minutes.
Turn off the bottom element and turn on the top (broiler). Between 2 and
3 minutes, the solder will melt. (You watch through the glass door).

Turn off. Done. Wash boards.  Great for hobby projects or engineering
prototypes. Makes you appreciate having a good assembly house for the
real stuff.

You can do boards with parts on both sides but make sure the board has
cooled before picking it up after the second side.  I got in a hurry
once and shook off half the parts from the bottom because it was still
hot.  Doh!  :(


2006\01\10@110221 by Alan B. Pearce

face picon face
>Am I correct with the understanding that:
>1. One simply applies it to each of the pads
>2. It is tacky, so the SM Part will "stick" to it.

As others have said, this is essentially correct.

>3. You can "touch" each pin with the soldering iron
>(or with Hot Air if you have the tool).

If you do this, you will probably end up with what is known as "tombstoning"
where the component stands up on end like a tombstone. Most common problem
with resistors and ceramic capacitors, but could happen to some degree to
other small components.

>4. Get next part....
>5. Go to 1.

It may be better to make a "toaster oven" to do a complete PCB in. Then you
repeatedly do steps 1 & 2 until all components are loaded, then put the
board in the oven. The paste is then melted using the heaters and all
components get soldered at once. This greatly reduces the problem with
tombstoning and also many hassles when doing fine pitch parts. However doing
a double sided PCB could be a problem, as parts on the bottom side may fall
off ;)

See the Seattle Robotics web page at
http://www.seattlerobotics.org/encoder/200006/oven_art.htm for an example of
how this can be done. The current issue of the European electronics magazine
Elector has a project for modifying a toaster oven with an AVR to control
the temperature profile. Small toaster ovens can be found very cheap on eBay
(I got one for 1 GBP here in the UK, and a mate who lived nearby picked it
up for me). They can be known as "toaster oven" or "mini oven" when
searching for them.

2006\01\10@112044 by Cris Wilson

flavicon
face

>Is this something that is feasable with limited resources/budget?

From a hobby point of view where time is not limited, you can deal with
burnt fingertip every now and then, and you expect to have a blown part
occasionally, it can be done with a limited budget.

The cheapest setup is:
A soldering iron  (25-40W)
Small diameter solder  ( 0.032" diameter)
Desoldering wick
A razor blade (to cut traces)
A multimeter (to check for shorts)
Fine grit sandpaper
Time - lots of time

Basically, you section the board with the razor blade to create copper
paths instead of wires.
Then, check all of the sections with the multimeter to make sure there is
no short between
it and the sections besides it. If so, run the razor blade through it
again, recheck it. Once the
board is short free, use the soldering iron to heat up the copper paths and
melt a tiny drop of
solder where the components will connect to the copper path. Check for
shorts again and remove
the offending the solder that caused the shorts with the razor blade or the
desoldering wick.
Now stick a component where you want it on top of it's small drop of
solder. Heat the copper
path up until the solder melts and push down on the part with your finger
to "stick it" to the board.
Check for shorts and fix them again. Continue with the rest of the parts
the same way.
Surprisingly, at least to me, most of the resistors, capacitors, and
inductors can take a lot of heat
before not working so don't worry to much at first that it seems to be
taking to long to get the part
situated.

From there you can build onto your SMT equipment and I would recommend:
A temperature controlled soldering iron
A lighted 5-10x magnifying lamp   ($35 US at most office supply stores)
A board etcher (outsourced, chemical, or mechanical)
A good desolderer
A pair of tweezers to place and hold the components so you don't burn yourself
An Aloe plant to help with the burns  ;-)

Good luck!



_____________________________________________________________
Cris Wilson
Information Resource Consultant
College of Architecture, Arts, and Humanities
Clemson University
KILLspamcrisKILLspamspamclemson.edu
To report problems email: RemoveMEaah_computersTakeThisOuTspamclemson.edu




                               

More... (looser matching)
- Last day of these posts
- In 2006 , 2007 only
- Today
- New search...