SMD techniques

- B
- bill.sloman
  
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posted
19 years ago

Thu, Mar 31, 2005 3:03 PM

Life is easiest if you put both sorts of components on the same side of the board - putting SMD components on the track side the board means that they have to be glued down before the board can be reflow soldered

- it isn't a big deal, but ti is an extra operation.

Solder-paste masks work the same way as every other mask - you don't need special alignment masks (at least not anywhere I've worked).

The printed circuit board house that makes your boards should be able to tell you all about this sort of stuff.

---------- Bill Sloman, Nijmegen

- P
- PigPOg
  
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posted
19 years ago

Thu, Mar 31, 2005 11:18 PM

Hi, can anyone help please?

I have to migrate a number of designs from PTH to Surface mount. Can anyone suggest a concise book or on-line resource that can answer questions such as: -

Do I put mixed (PTH and SMD) components on the same side of the PCB or on opposite sides and what are the associated merits/disadvantages?

and...

When generating the solder-paste mask what alignment marks do PCB manufacturers generally require?

These are but two of many questions I have. I'd be most grateful for any suggestions/advice.

Cheers, Simon

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- PigPOg
  
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posted
19 years ago

Fri, Apr 1, 2005 12:36 AM

Thanks for the info Bill.

Simon

- F
- Fred Bartoli
  
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posted
19 years ago

Fri, Apr 1, 2005 8:23 PM

a écrit dans le message de news: snipped-for-privacy@g14g2000cwa.googlegroups.com...

Sure, but on the other side :

Having both components variety on the same side requires 2 additional operations:

- solder past screening

- oven reflow that are not necessary if the SMD components are soldered along with the TH ones.

If _all_ the components can withstand wave soldering the most economical way would be SMD on track side, and just one soldering pass.

--
Thanks,
Fred.

- A
- Apparatus
  
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posted
19 years ago

Mon, Apr 4, 2005 11:05 AM

I usually put SMT debouncing caps on the bottom of the board and everything else on top. I'm a hobbyist though -- not sure how well this works in mass production.

Be sure to put thermal reliefs on the power pins of the SMT pads, similar to through-hole thermal relief. On my first board I had some bad solder joints due to not putting these in.

Chris