What is faster? Trough hole or SMD?

Community PCB Design
1

I’m on the fence about switching to SMD.

I recently bought a 7000 part SMD passives kit, and some SMD parts to prototype. And now that I’ve received the 0805 parts - I want to get my head examined.

First off - the cost of the parts don’t seem that different - or am I wrong about that?

Right now I have a small board with 8 resistors, and 1 8-pin DIP (also some caps, 5 hookup wires, and one to-220.) It’s a load driver - nothing fancy.

http://dl.dropbox.com/u/2295566/test3.jpg

Obviously I know I’ll be saving space on the board with SMD, and therefor saving money on PCB costs.

The tools I’d be using are my brand new wesd51 Weller iron, a reflow oven or skillet(diy), and I’d order a kapton stencil.

My question is: Will converting the resistors, and DIP into SMD parts save time soldering? What will be faster?

Hand soldering SMD vs. TH?

Toaster oven/skillet reflow vs. TH?

Thanks - I took one look at those 0805’s and wanted to get the opinion of someone already doing it. Should I just forge on?

Thanks!

George

2

Hand soldering SMDs with a good tip on the WESD51 is no problem. I do it all the time for 0402 parts.

–David Carne

3

Good question, I’ll guess that at first the SMD parts are going to take much longer to solder. As you gain experience the time will decrease and may become shorter than thru-hole parts.

The big cost saving by using SMD parts is first in quanity, 0805 in 100’s may be about $0.05 each whereas on a reel of 3000 they are about $0.001 each.

The next cost saving is in auto pick and place of more than 100 boards per run.

4

I can solder surface mount parts wayyyyyy faster than through hole parts. It takes a bit of experience - but you’ll get used to it quickly enough.

5

OK - sounds like I’m just being a wimp. I’ll press on with SMD!

6

some surface mounts are way easier and faster…some imho take longer. (chips with a lot of contacts and VERY small gap between them can take a few tries sometimes…) The resistors and caps especially are WAYY easier to use the surface mount versions, especially if you use paste and a reflow oven. (or toaster oven as the case may be).

As an added bonus, when the paste liquifies, the surface tension PERFECTLY aligns your surface mount caps/resistors with the pads, so you end up with a really clean and pretty board.

7

george graves:
OK - sounds like I’m just being a wimp. I’ll press on with SMD!

Like any skill, the more you practice the better you’ll get. Before you know it, you will be soldering 0.4mm devices by hand without thinking about it.

My one mandatory tool is a pair of fine tweezers for placing small components and holding them in place while using an iron.

-Bill

8

I got a verity of tweezers from deal extreme to start me off.

http://www1.dealextreme.com/productimag … 9869_1.jpg

They are only $2 - so I bought 6 different kinds - I think I’ll be ok for a bit.

9

A decent magifier is also essential. I use a combination of a 3x magnifier lamp and a 10x jeweler’s loupe. I’ve found dry joints & damage to components that would have been impossible to spot without them.

10

Raptor85:
some surface mounts are way easier and faster…some imho take longer. (chips with a lot of contacts and VERY small gap between them can take a few tries sometimes…)

It takes a bit of practice, but with extra flux I can tack down 100+ lead TQFP/LQFP (0.5mm pitch) parts in about 2 minutes using a soldering iron. The only tricky part is making sure the part remains centered, and learning how much solder to use to prevent any bridging.