Having your PCB produced commercially - Through hole a big deal? Tips wanted!

Thread Starter

MrSoftware

Joined Oct 29, 2013
1,618
I'm hoping to have my own PCB manufactured commercially and I've never done this before. Is it a major deal if I use a mix of SMD and through-hole components, as opposed to all through-hole, or all SMD?

At the end of the day, I want to receive fully operational boards without having to populate or test anything myself. It's going to be a simple single sided PCB, probably less than 100 components. A mix of logic parts and power MOSFETs (IR receiver, 20A @14v H-bridge). All tips and/or assembly company recommendations are more than welcome!
 

Papabravo

Joined Feb 24, 2006
12,702
A single sided PCB for that number of components is hardly worth doing. All those through hole jumpers will eat up area and increase the number of hand operations. Your labor cost will kill you. You're far better off going with all SMD components on a multi-layer board. This will allow for completely automated pick 'n place, and reflow soldering. If you have through-hole components they will have to be handled in a separate wave soldering line and then the SMD components done in a second operation. It might be the other way around, but two soldering operations, wave and reflow, will increase your costs. Doing a single layer board is in my estimation a false economy, unless you're only going to make a handful and they will be hand assembled by actual people.

You'll also have to supply functional test fixtures to your contract manufacturer if you want fully operational and tested boards. This will cost you big time.

Contract manufacturers really don't want to get involved in testing. They have neither the equipment, nor the expertise to do an adequate job. A board that does not power up and work out of the box can be returned for credit and or detail inspection and rework. It will cost you very little to do this binary sort.
 
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tracecom

Joined Apr 16, 2010
3,944
You can get a fairly quick quote from Itead.

I would be very surprised to see a single sided PCB with 100 components, and even more surprised to see one with a mix of SMD and through-hole components.
 

Thread Starter

MrSoftware

Joined Oct 29, 2013
1,618
Thanks guys, reading your posts I see that my typing got ahead of my brain... I was envisioning components on one side, but traces on both sides if I use some SMD parts, so I guess that makes it a multi-layered board. So I am expecting a 2 layer board, and I guess my real question is would there be a big assembly price difference between all SMD, a mix of SMD and through hole, or all through hole?

@tracecom - Thanks, I will check that out!
 

Papabravo

Joined Feb 24, 2006
12,702
Thanks guys, reading your posts I see that my typing got ahead of my brain... I was envisioning components on one side, but traces on both sides if I use some SMD parts, so I guess that makes it a multi-layered board. So I am expecting a 2 layer board, and I guess my real question is would there be a big assembly price difference between all SMD, a mix of SMD and through hole, or all through hole?

@tracecom - Thanks, I will check that out!
I would expect all SMD would be the lowest cost option. After that it might be a dogfight unless the contract manufacturers had to get rid of, or cannot maintain their wave solder machines. In that case through hole assembly by people will become cost prohibitive.
 

SLK001

Joined Nov 29, 2011
1,541
Thru-hole and SMD require two different lines. If the part is available in SMD, then use SMD, regardless of the increased cost. Any thru-hole parts will probably have to be hand placed and soldered, which will make your costs soar.
 

Papabravo

Joined Feb 24, 2006
12,702
Thru-hole and SMD require two different lines. If the part is available in SMD, then use SMD, regardless of the increased cost. Any thru-hole parts will probably have to be hand placed and soldered, which will make your costs soar.
What he said.
 

ErnieM

Joined Apr 24, 2011
8,010
I have seen the terminology migrate over what "single sided" and "double sided" boards mean over the years.

Initially single sided meant only copper traces on one side of the board. At least a decade ago this migrated to having parts on only one side, as SMD came to predominate and double or multilayer boards were the norm.

Sticking to double sided coper boards with SMD on one side only is the cheapest way to go. When mixing SMD and thru hole the thru hole stuff gets hand soldered at the last step. Thru hole hand work is $$$.

You may be best served by farming out the SMD assemble and hand soldering the rest yourself on your kitchen table.
 

Papabravo

Joined Feb 24, 2006
12,702
I'm not an expert on manufacturing techniques, but I could swear there were people who claimed you could reflow components on both sides, then place the thru-hole components and run the boards through a wave solder process without disturbing the SMT parts on the 'solder side' of the board.
 

Thread Starter

MrSoftware

Joined Oct 29, 2013
1,618
It sounds like the general theme is go all SMD if at all possible, so this will be my goal.

Assuming some parts are only available as through hole (maybe the large MOSFETs), am I better in this case to make everything through hole and try to find a shop that still has a wave solder machine in operation?

<EDIT> I see the MOSFETs I was worried about are available in TO-252-3 surface mount, so I might be able to find all SMD devices, yahoo!
 
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Papabravo

Joined Feb 24, 2006
12,702
It sounds like the general theme is go all SMD if at all possible, so this will be my goal.

Assuming some parts are only available as through hole (maybe the large MOSFETs), am I better in this case to make everything through hole and try to find a shop that still has a wave solder machine in operation?

<EDIT> I see the MOSFETs I was worried about are available in TO-252-3 surface mount, so I might be able to find all SMD devices, yahoo!
I don't think there is a simple answer. It all depends on how hungry the vendor is to get your business. You might have to run the BOM in multiple configurations or you might just decide for political reasons to go one way or the other. I will tell you this, if you can afford to get components on tape & reel you will save substantial $$$ in material handling cost. Loose, thru-hole components are an incredible pain in the ass to deal with. Next if you can design with components on the assembly house approved component list you will save over having to procure your own. You need to work with the assembly house before the design stage even begins to give them board outlines and preliminary BOMs so the can quote material acquisition prices and lead times. You also need to decide who is going to procure and inventory specialty components. Don't overlook the benefits on using a handful of standard values for all resistors and capacitors. The assembly house will give you a break for that.
 
Last edited:

SLK001

Joined Nov 29, 2011
1,541
I'm not an expert on manufacturing techniques, but I could swear there were people who claimed you could reflow components on both sides, then place the thru-hole components and run the boards through a wave solder process without disturbing the SMT parts on the 'solder side' of the board.
Yeah, as long as the "wave solder process" was some chick with a soldering iron!
 

ErnieM

Joined Apr 24, 2011
8,010
I don't know about wave soldering the whole thing but... we have spot wave machines, one with an about 3/4" wave, the other about 3/4 by a few inches.

The smaller one is used to spot wave a single device. The larger for long connectors.

I have heard of wave soldering an entire SMD board but I have never seen it done.
 

RichardO

Joined May 4, 2013
2,268
Thru-hole and SMD require two different lines. If the part is available in SMD, then use SMD, regardless of the increased cost. Any thru-hole parts will probably have to be hand placed and soldered, which will make your costs soar.
Yup. One assembly house I have worked with abhors through parts and charges accordingly. :(
 

mcgyvr

Joined Oct 15, 2009
5,394
All depends on the equipment the board house has..
In general its "best" to stay with one technology vs mixed (th/smt)..

I've seen lines with wave solder, reflow ovens and selective soldering machines all in the same line that can handle it no problems..
And others where as stated above its a lady with a soldering iron at the end post reflow stuffing th components and soldering..
And other times you may find the "pin in paste" method for th can be used just fine..

But with anything.. more operations = more money
 
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