Thru-Hole and Surface mount? Costs.

[Mike V.]

Being a software and firmware guy most my life, only now am I doing
layout (or hiring someone's services to do it for me) of a 4-layer
PCB.

I have a few questions:

1. How much can I save by going surface mount vs thru hole, in terms
of:
* costs of thru hole parts vs surface mount counterparts.
* cost for service to stuff a thru hole board vs a surface mount
board.
(I heard I can save up to 20% of the costs on the manufacturing part).

2. I looked at websites that offer online quotes for manufacturing the
PCB once you give them your gerber files. They ask how many "holes"
will be in the board, and the sizes of the holes. With thru-hole, it's
easy to see that each pin of the component or leg of a resistor or
capacitor constitutes a hole. Is a surface mount part also considered
a "hole" that i should account for when getting a price quote?

Thanks,
Mike

 

[Paul Burke]

Mike V. wrote:

1. How much can I save by going surface mount vs thru hole, in terms
of:
* costs of thru hole parts vs surface mount counterparts.
* cost for service to stuff a thru hole board vs a surface mount
board.
(I heard I can save up to 20% of the costs on the manufacturing part).

Some components are cheaper, some more expensive, and some about the
same! In small quantities, using hand assembly, SM usually costs rather
more. In large quantities, with assembly automated, it is usually
cheaper (comparing like with like). Don't forget the saving on PCB size
and the ability to populate both sides (though this pushes up assembly
costs). Testing is often easier with through hole, and you get fewer
problems due to components that look stuck down but aren't.

2. I looked at websites that offer online quotes for manufacturing the
PCB once you give them your gerber files. They ask how many "holes"
will be in the board, and the sizes of the holes. With thru-hole, it's
easy to see that each pin of the component or leg of a resistor or
capacitor constitutes a hole. Is a surface mount part also considered
a "hole" that i should account for when getting a price quote?

They are interested in the number of drill operations and the number of
times they have to change drill size. So an SM pad will not add to their
costs. On the other hand, pin- limited CAD packages are interested in
limiting the functionality you get out of them, so SM pads count as pins
there.

Paul Burke

 

[John Devereux]

valemike@yahoo.com (Mike V.) writes:

Being a software and firmware guy most my life, only now am I doing
layout (or hiring someone's services to do it for me) of a 4-layer
PCB.

I have a few questions:

1. How much can I save by going surface mount vs thru hole, in terms
of:
* costs of thru hole parts vs surface mount counterparts.

I am going through this process too (so don't take the below as
gospel!).

This will depend on the mix of components and the quantities.

There isn't much difference with IC pricing, (although very many new
chips are only available in SMT).

Most passives are cheaper in SMT, but for me this is not too
important since these are only a small portion of the parts cost
anyway. For example, resistors are say $0.002 each in SMT vs $0.01 for
through hole. But they both cost me $0.05 to place (small qty
production). And there is a $15 IC on the board anyway.

The main saving is probably in the board, especially 4 layer which
tends to be charged by the square inch. Then again maybe you only had
to go 4 layer because you went surface mount...

I think there are higher initial costs with SMT such as the solder
paste screen (~$120), placement machine programming, prototype
construction. ICs may *only* be available on reels of 2,500 when you
are only ever going to make 100 boards. Anyone want 2,400 BA6845
stepper motor drivers ?

* cost for service to stuff a thru hole board vs a surface mount
board.
(I heard I can save up to 20% of the costs on the manufacturing part).

I think you will have to get quotes for your specific quantities and
parts mix - there seems to be quite a large variation. Also you may be
able to tailor your design for lowest cost from a particular
supplier. For example, if they quote per placement, use lots of
resistor / capacitor / diode arrays instead of individual parts.

2. I looked at websites that offer online quotes for manufacturing the
PCB once you give them your gerber files. They ask how many "holes"
will be in the board, and the sizes of the holes. With thru-hole, it's
easy to see that each pin of the component or leg of a resistor or
capacitor constitutes a hole. Is a surface mount part also considered
a "hole" that i should account for when getting a price quote?

Probably. The ones I have seen use the number of component
pads. However if they are just quoting per "hole" they may not be
thinking of SMT at all, or may have a completely different pricing
structure for this.



--

John Devereux

 

[Spehro Pefhany]

On 28 Aug 2003 22:08:30 -0700, the renowned valemike@yahoo.com (Mike
V.) wrote:

Being a software and firmware guy most my life, only now am I doing
layout (or hiring someone's services to do it for me) of a 4-layer
PCB.

I have a few questions:

1. How much can I save by going surface mount vs thru hole, in terms
of:
* costs of thru hole parts vs surface mount counterparts.

Depends on the parts. You may not be able to get some parts in through
hole any more (and some were never introduced in through-hole in the
first place). If you insist on all-SMT rather than "mixed, mostly SMT"
you may push the cost up quite a bit, as things like transformers,
terminal blocks, switches and such like don't translate that well to
SMT, and LEDs have some issues.

* cost for service to stuff a thru hole board vs a surface mount
board.

Depends on the quantity. Hand assembly of SMT is typically slower,
IME, but it can be economically automated at relatively low quantities
(low thousands). The solder paste stencil and other setup costs make
it a bit pricey to do just a couple of hundred boards.

(I heard I can save up to 20% of the costs on the manufacturing part).

Don't forget the board will usually be smaller with SMT. Components
are smaller so they take up less store-room space.

2. I looked at websites that offer online quotes for manufacturing the
PCB once you give them your gerber files. They ask how many "holes"
will be in the board, and the sizes of the holes. With thru-hole, it's
easy to see that each pin of the component or leg of a resistor or
capacitor constitutes a hole. Is a surface mount part also considered
a "hole" that i should account for when getting a price quote?

No, it isn't. But typically, IME, the number of holes doesn't affect
the price of the PCB in quantities over 100 or 500 pieces, it's mostly
square inches, order quantity and specifications. The finish of the
PCB may have to be different for SMT etc. etc.

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[John Devereux]

novatech@eskimo.com (Steven Swift) writes:

Function for function, SMT is almost always MORE expensive than thru-hole.
However, you can cram more on a board with SMT. The most expensive is
mixing. Try to get only one process per board.

Not sure I agree here about mixing. Like Speff said, there are usually
some parts which are disproportionately expensive in SMT. In any case,
for me there always seems to be something that *must* be through
hole. Once you admit one through hole part it opens the door for the
others, where they are convenient.

(My experience is limited to relatively small quantity however)


--

John Devereux

 

[Steven Swift]

John Devereux <jd1@devereux.me.uk> writes:

novatech@eskimo.com (Steven Swift) writes:

Function for function, SMT is almost always MORE expensive than thru-hole.
However, you can cram more on a board with SMT. The most expensive is
mixing. Try to get only one process per board.

Not sure I agree here about mixing. Like Speff said, there are usually
some parts which are disproportionately expensive in SMT. In any case,
for me there always seems to be something that *must* be through
hole. Once you admit one through hole part it opens the door for the
others, where they are convenient.

(My experience is limited to relatively small quantity however)

In low quants you are right. Above a few thousand piece per run, you
can greatly increase the manufacturing costs by adding processes.

--

John Devereux
--

Steven D. Swift, novatech@eskimo.com, http://www.novatech-instr.com
NOVATECH INSTRUMENTS, INC. P.O. Box 55997
206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA