Surface mount heck

[EBG]

I'm delving into my first attempt at an SMT chip and was wondering....

(1) has anyone had success using a Weller wes50 and what....maybe an ETR
tip? ETS? what setiing on the iron?
12 oclock etc? (or should I just go for a 15 watt designed for SMT?)


(2) whats the adhesive you use to hold it in place?
MCM part number or brand?


(3) is there such a thing as a hot air system that will actually reflow
solder on very small areas? like a small nozzle that you point to chip pins
(probably not, right?)


(4) is there any kind of liquid solder out there now that is
being used on SMT by chance?

 

[John Larkin]

On Thu, 11 Dec 2003 09:43:11 -0500, "EBG" <maberger@comcast.net>
wrote:

I'm delving into my first attempt at an SMT chip and was wondering....

(1) has anyone had success using a Weller wes50 and what....maybe an ETR
tip? ETS? what setiing on the iron?
12 oclock etc? (or should I just go for a 15 watt designed for SMT?)

Most any small-tip iron will work, even a cheap RatShack, although
better is always better. Just try it.

(2) whats the adhesive you use to hold it in place?
MCM part number or brand?

Most people don't glue the parts. Parts are occasionally glued to the
bottom of the board in production applications where both sides are
soldered in one pass. In my shop, we stencil paste,pick-n-place, and
reflow the top, and hand-solder the bottom parts.

For hand assembly, just solder the little buggers.

I've heard of people applying solder paste from a syringe, placing
parts by hand, and reflowing in a toaster over.

(3) is there such a thing as a hot air system that will actually reflow
solder on very small areas? like a small nozzle that you point to chip pins
(probably not, right?)

Hot air usually just blows the parts around.

(4) is there any kind of liquid solder out there now that is
being used on SMT by chance?

Production generally uses stenciled solder paste. Most everybody hand
solders with fine roll solder. For fine pitch ICs, smaller than 50 mil
pitch,

solder two corner pins by hand
slosh liquid flux on remaining pins
put a blob of solder on your tip and run it down the line of pins

We just sent some BGAs out to be soldered and xray inspected. The
contractor added no solder at all - just used the solder coating on
the traces, and some flux - and it worked fine.

John

 

[Tim Wescott]

This matches my experience. I'm not sure of your Weller part number, but if
you've never used on a temperature controlled soldering iron is heaven
compared to the fixed-power ones. If you do much soldering at all it's a
good buy.

I've seen kits that claim to make the toaster oven method reliable, with
little plastic cones that melt at the right temperature for calibrating your
oven. The company is either PCB Express or Express PCB (they both exist,
but only one sells the toaster oven reflow kits and cheap stencils).

At my last job we had reliability problems with soldering large (600-700
ball) BGAs with just the solder mask and flux on prototypes. On our
production stuff we _always_ used stencils and solder paste.

"John Larkin" <jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote in
message news:2m6htv4do3ocr03v1tbtltajum3r74g7rg@4ax.com...

On Thu, 11 Dec 2003 09:43:11 -0500, "EBG" <maberger@comcast.net
wrote:

I'm delving into my first attempt at an SMT chip and was wondering....

(1) has anyone had success using a Weller wes50 and what....maybe an ETR
tip? ETS? what setiing on the iron?
12 oclock etc? (or should I just go for a 15 watt designed for SMT?)



Most any small-tip iron will work, even a cheap RatShack, although
better is always better. Just try it.

(2) whats the adhesive you use to hold it in place?
MCM part number or brand?

Most people don't glue the parts. Parts are occasionally glued to the
bottom of the board in production applications where both sides are
soldered in one pass. In my shop, we stencil paste,pick-n-place, and
reflow the top, and hand-solder the bottom parts.

For hand assembly, just solder the little buggers.

I've heard of people applying solder paste from a syringe, placing
parts by hand, and reflowing in a toaster over.

(3) is there such a thing as a hot air system that will actually reflow
solder on very small areas? like a small nozzle that you point to chip
pins
(probably not, right?)


Hot air usually just blows the parts around.


(4) is there any kind of liquid solder out there now that is
being used on SMT by chance?


Production generally uses stenciled solder paste. Most everybody hand
solders with fine roll solder. For fine pitch ICs, smaller than 50 mil
pitch,

solder two corner pins by hand
slosh liquid flux on remaining pins
put a blob of solder on your tip and run it down the line of pins

We just sent some BGAs out to be soldered and xray inspected. The
contractor added no solder at all - just used the solder coating on
the traces, and some flux - and it worked fine.

John

 

[John Larkin]

On Thu, 11 Dec 2003 11:16:25 -0800, "Tim Wescott"
<tim@wescottnospamdesign.com> wrote:

This matches my experience. I'm not sure of your Weller part number, but if
you've never used on a temperature controlled soldering iron is heaven
compared to the fixed-power ones. If you do much soldering at all it's a
good buy.

Metcal! Their irons are expensive and worth it. They do show up on
ebay.

At my last job we had reliability problems with soldering large (600-700
ball) BGAs with just the solder mask and flux on prototypes. On our
production stuff we _always_ used stencils and solder paste.

Um, then wish us luck. The guys we sent it to seem to know what
they're doing. They did say that the time-temperature profile is
critical, and they did xray the critters afterwards.

John

 

[Robert Baer]

EBG wrote:

I'm delving into my first attempt at an SMT chip and was wondering....

(1) has anyone had success using a Weller wes50 and what....maybe an ETR
tip? ETS? what setiing on the iron?
12 oclock etc? (or should I just go for a 15 watt designed for SMT?)

(2) whats the adhesive you use to hold it in place?
MCM part number or brand?

(3) is there such a thing as a hot air system that will actually reflow
solder on very small areas? like a small nozzle that you point to chip pins
(probably not, right?)

(4) is there any kind of liquid solder out there now that is
being used on SMT by chance?

I use an old GE 25W iron and a light dimmer to keep the temperature
down (latter not really needed if fast).
I hold the part dowm with a toothpick and tack on one lead to start;
go around and do the others, and return and re-fresh the first lead.
For SOT-363 and SOT-23 5-leaded parts, i have found that if i put a
thin film of solder on the pads first, align the part on top, i can use
the iron on the 3 leads on one side (a bit away from the part) to heat
up all of the traces - and cause a re-flow that is extremely satisfying.
But i cheat: i use a flux pen and wet the traces *and* the part leads
(bottom side) first.

Possible problems with hot air: too much air flow will blow the part
away (and you cannot find it in the dirt).

 

[Roger Gt]

"Robert Baer" wrote in message

EBG wrote:

I'm delving into my first attempt at an SMT chip and was wondering....
(1) has anyone had success using a Weller wes50 and what....maybe an ETR
tip? ETS? what setiing on the iron?
12 oclock etc? (or should I just go for a 15 watt designed for SMT?)
(2) whats the adhesive you use to hold it in place?
MCM part number or brand?
(3) is there such a thing as a hot air system that will actually reflow
solder on very small areas? like a small nozzle that you point to chip
pins
(probably not, right?)
(4) is there any kind of liquid solder out there now that is
being used on SMT by chance?
I use an old GE 25W iron and a light dimmer to keep the temperature
down (latter not really needed if fast).
I hold the part dowm with a toothpick and tack on one lead to start;
go around and do the others, and return and re-fresh the first lead.
For SOT-363 and SOT-23 5-leaded parts, i have found that if i put a
thin film of solder on the pads first, align the part on top, i can use
the iron on the 3 leads on one side (a bit away from the part) to heat
up all of the traces - and cause a re-flow that is extremely satisfying.
But i cheat: i use a flux pen and wet the traces *and* the part leads
(bottom side) first.

Possible problems with hot air: too much air flow will blow the part
away (and you cannot find it in the dirt).

I constructed a hot air source using a 3/8 inch quartz tube with one end
formed down to a .020 inch opening, the tube is 5 inches long and in the
tube wound on a ceramic mandrel is forty turns of NiChrome heater wire. The
air used is dry nitrogen and a flow regulator to set the volume. I use a
setting of 20CC per minute. Temperature is set with a low voltage regulated
supply. Been using this method since I needed to attach leads to quartz
crystals, and it works great for small surface mount parts.

 

[Tim Wescott]

I'm not an expert in the process, so I'm not saying it _can't_ be done, just
that we didn't have good luck with it ourselves -- and having 700 balls that
all must be right increases your probability of failure. If it works for
you then more power to you and your board assembly guys, you can always go
to a stencil later.

X-ray images do a good job of showing bridged solder joints, which you're
not going to get when there isn't enough solder. It doesn't do a good job
of showing a cold solder joint or one where the ball was just too small,
which seemed to be the problem we were having.

"John Larkin" <jjlarkin@highSNIPlandTHIStechPLEASEnology.com> wrote in
message news:3clhtv8p3emkt2i0j5tin9t3dga0v54cne@4ax.com...

On Thu, 11 Dec 2003 11:16:25 -0800, "Tim Wescott"
tim@wescottnospamdesign.com> wrote:

-- snip --

Um, then wish us luck. The guys we sent it to seem to know what
they're doing. They did say that the time-temperature profile is
critical, and they did xray the critters afterwards.

John

 

[Roger Gt]

I did not recommend using a point of hot air for a ball grid array. A wave
with very precise control would be needed for that.

For the SOT23 and 2 to 8 pin SMT devices the point hot air works well.


"Tim Wescott" <tim@wescottnospamdesign.com> wrote in message
news:vti74mcqpcet88@corp.supernews.com...

I'm not an expert in the process, so I'm not saying it _can't_ be done,
just
that we didn't have good luck with it ourselves -- and having 700 balls
that
all must be right increases your probability of failure. If it works for
you then more power to you and your board assembly guys, you can always go
to a stencil later.

X-ray images do a good job of showing bridged solder joints, which you're
not going to get when there isn't enough solder. It doesn't do a good job
of showing a cold solder joint or one where the ball was just too small,
which seemed to be the problem we were having.

-- snip --
Um, then wish us luck. The guys we sent it to seem to know what
they're doing. They did say that the time-temperature profile is
critical, and they did xray the critters afterwards.
John

 

[EBG]

What is a good basic hot air system, not for production, just onezees and
twozees?

Anything I could pick up on Ebay? model numbers?

Does a quality (milwaukee) hot air gun work? Has anyone done a homebrew
adapter on one?




"Roger Gt" <Xenot@pacbell.net> wrote in message
news:mK6Cb.70093$Hs6.23532@newssvr25.news.prodigy.com...

"Robert Baer" wrote in message
EBG wrote:

I'm delving into my first attempt at an SMT chip and was wondering....
(1) has anyone had success using a Weller wes50 and what....maybe an
ETR
tip? ETS? what setiing on the iron?
12 oclock etc? (or should I just go for a 15 watt designed for SMT?)
(2) whats the adhesive you use to hold it in place?
MCM part number or brand?
(3) is there such a thing as a hot air system that will actually
reflow
solder on very small areas? like a small nozzle that you point to chip
pins
(probably not, right?)
(4) is there any kind of liquid solder out there now that is
being used on SMT by chance?
I use an old GE 25W iron and a light dimmer to keep the temperature
down (latter not really needed if fast).
I hold the part dowm with a toothpick and tack on one lead to start;
go around and do the others, and return and re-fresh the first lead.
For SOT-363 and SOT-23 5-leaded parts, i have found that if i put a
thin film of solder on the pads first, align the part on top, i can use
the iron on the 3 leads on one side (a bit away from the part) to heat
up all of the traces - and cause a re-flow that is extremely satisfying.
But i cheat: i use a flux pen and wet the traces *and* the part leads
(bottom side) first.

Possible problems with hot air: too much air flow will blow the part
away (and you cannot find it in the dirt).

I constructed a hot air source using a 3/8 inch quartz tube with one end
formed down to a .020 inch opening, the tube is 5 inches long and in the
tube wound on a ceramic mandrel is forty turns of NiChrome heater wire.
The
air used is dry nitrogen and a flow regulator to set the volume. I use a
setting of 20CC per minute. Temperature is set with a low voltage
regulated
supply. Been using this method since I needed to attach leads to quartz
crystals, and it works great for small surface mount parts.

 

On Thu, 11 Dec 2003 08:36:35 -0800, John Larkin
<jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote:

On Thu, 11 Dec 2003 09:43:11 -0500, "EBG" <maberger@comcast.net
wrote:

I'm delving into my first attempt at an SMT chip and was wondering....


We just sent some BGAs out to be soldered and xray inspected. The
contractor added no solder at all - just used the solder coating on
the traces, and some flux - and it worked fine.

John

How much does it cost to have a BGA part soldered onto a prototype
board?

 

[Keith R. Williams]

In article <lfijtvs6m6qa4p0e2fmen2jd0juvcjpd94@4ax.com>,
Weblurker@nomail.com says...

On Thu, 11 Dec 2003 08:36:35 -0800, John Larkin
jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote:

On Thu, 11 Dec 2003 09:43:11 -0500, "EBG" <maberger@comcast.net
wrote:

I'm delving into my first attempt at an SMT chip and was wondering....


We just sent some BGAs out to be soldered and xray inspected. The
contractor added no solder at all - just used the solder coating on
the traces, and some flux - and it worked fine.

John

How much does it cost to have a BGA part soldered onto a prototype
board?

Not that much. I had two BGA256 parts replaced (one each on two
boards) for a hundred bucks by our prototype house a while back. That
included XRay inspection before (open balls) and after.

--
Keith

 

[Roger Gt]

"EBG" <maberger@comcast.net> wrote in message
news:Qs6dnXwkw64wKUSiRVn-hA@comcast.com...

Roger Gt wrote

I constructed a hot air source using a 3/8 inch quartz tube with one end
formed down to a .020 inch opening, the tube is 5 inches long and in the
tube wound on a ceramic mandrel is forty turns of NiChrome heater wire.
The air used is dry nitrogen and a flow regulator to set the volume. I
use a
setting of 20CC per minute. Temperature is set with a low voltage
regulated
supply. Been using this method since I needed to attach leads to
quartz
crystals, and it works great for small surface mount parts.

What is a good basic hot air system, not for production, just onezees and
twozees?

When we devised this configuration, it was to produce 12,000 crystals a day
with 24 stations. It all depends on how you apply the method. Of
course there is only one connection made each time, but a turntable with two
hundred crystals went pretty fast!

 

[Lewin A.R.W. Edwards]

How much does it cost to have a BGA part soldered onto a prototype
board?

Not that much. I had two BGA256 parts replaced (one each on two
boards) for a hundred bucks by our prototype house a while back. That

That sounds really reasonable. May I ask who you use? And, do you do a
lot of business with them, or is that their "walk-in customer" rate?
I've got occasional use for mounting a few MBGAs.

 

[Mac]

On Fri, 12 Dec 2003 07:30:15 +0000, EBG wrote:

What is a good basic hot air system, not for production, just onezees and
twozees?

Anything I could pick up on Ebay? model numbers?

Does a quality (milwaukee) hot air gun work? Has anyone done a homebrew
adapter on one?

I would not try to use hot air. A soldering iron works just fine for
surface mount parts. For two-terminal devices, two irons are best. You
place the part on the pads, then touch both sides at the same time and
move away evenly. For fine pitch parts and small resistors/capacitors (805
and 603) it helps to have a microscope.

Any thermostatically controlled soldering iron should work. Hakko and
Weller are two quality brands that aren't too expensive.

Mac

 

I have long used a hot-air pencil and solder paste. You have
to hold most parts down, but it is an easy and forgiving system.


On Thu, 11 Dec 2003 09:43:11 -0500, "EBG" <maberger@comcast.net>
wrote:

I'm delving into my first attempt at an SMT chip and was wondering....

(1) has anyone had success using a Weller wes50 and what....maybe an ETR
tip? ETS? what setiing on the iron?
12 oclock etc? (or should I just go for a 15 watt designed for SMT?)


(2) whats the adhesive you use to hold it in place?
MCM part number or brand?


(3) is there such a thing as a hot air system that will actually reflow
solder on very small areas? like a small nozzle that you point to chip pins
(probably not, right?)


(4) is there any kind of liquid solder out there now that is
being used on SMT by chance?