Electronics Assembly Manufacturing Question

[[email protected]]

I have a board with mixed surface mount parts and thru hole parts.
Furthermore, there are smt parts on both sides of the board. I would
like to have the smt stuff soldered on by the assembly house, and i can
solder the few thru-hole parts on myself, so to avoid extra assembly
costs.

For those of you familiar with the assembly process, how do they do it?
Do they place the SMT stuff on one side first, solder it, then the
other side and solder that? What do they do with all the vias and
thruhole holes? Do they put some type of latex-like gum on them to
prevent the smt soldering process from filling up those holes?

Reason why i ask is that it may actually take more effort to prevent
the thru-hole pads from getting filled up with solder during the
initial smt parts soldering, that I may as well just let them stuff the
thru-hole stuff too.

Thanks,
Mike

 

[John Larkin]

I have a board with mixed surface mount parts and thru hole parts.
Furthermore, there are smt parts on both sides of the board. I would
like to have the smt stuff soldered on by the assembly house, and i can
solder the few thru-hole parts on myself, so to avoid extra assembly
costs.

For those of you familiar with the assembly process, how do they do it?
Do they place the SMT stuff on one side first, solder it, then the
other side and solder that? What do they do with all the vias and
thruhole holes? Do they put some type of latex-like gum on them to
prevent the smt soldering process from filling up those holes?

Reason why i ask is that it may actually take more effort to prevent
the thru-hole pads from getting filled up with solder during the
initial smt parts soldering, that I may as well just let them stuff the
thru-hole stuff too.

Thanks,
Mike

What we do is


Paste the bottom; use glue for big parts.

Place bottom parts.

Reflow

Paste top

Place top parts

Reflow

Place and solder thru-hole by hand.

The thru-holes stay clear during the surfmount steps.



I think some people glue all the bottom parts and wave solder the
thru-holes and the bottom parts in a wave solder machine.

Why not let them do it all?

John

 

[John Woodgate]

I read in sci.electronics.design that John Larkin

Why not let them do it all?

It avoids questions of who is responsible when the boards don't work.
That can be worth $$$$.

 

[Spehro Pefhany]

I have a board with mixed surface mount parts and thru hole parts.
Furthermore, there are smt parts on both sides of the board. I would
like to have the smt stuff soldered on by the assembly house, and i can
solder the few thru-hole parts on myself, so to avoid extra assembly
costs.

For those of you familiar with the assembly process, how do they do it?
Do they place the SMT stuff on one side first, solder it, then the
other side and solder that? What do they do with all the vias and
thruhole holes? Do they put some type of latex-like gum on them to
prevent the smt soldering process from filling up those holes?

Reason why i ask is that it may actually take more effort to prevent
the thru-hole pads from getting filled up with solder during the
initial smt parts soldering, that I may as well just let them stuff the
thru-hole stuff too.

Thanks,
Mike

They can typically do this, and it can be a reasonable course of
action. Talk to your assembly house and get quotes both ways.


Best regards,
Spehro Pefhany

 

[[email protected]]

Thanks for the replies John, John, and Spehro. I have gotten quotes to
do it both ways. If i let them do the smt stuff only, it would cost
$25. To do the few thru-hole parts in addition, it would then cost a
total of $45. Since we're a small startup with this small initial
production run, then the $20 savings is worth doing it in-house.

As long as my thru-hole pads go untouched when i get the partially
assembled boards, which they are, then it's all good.

Thanks!
Mike