The very cheapest, nastiest PCBs

[djacobow]

I've been poking around with making my own PCBs from OSH Park, Seeed, etc, and have gradually been transitioning from all TH to partly SMT to mostly SMT designs. Part of the reason is access to more chips, but also SMT components just seem cheaper in general and they're smaller, too, which leads to smaller board, which is also cheaper. And with SMT and paste and stencil, I can assemble the board quickly -- saving more time and I guess cost. Add in automation, and SMT is a very strong win.

But I notice that the VERY cheapest piece-of-sh*t boards are always through hole. Typically, they're one sided, phenolic, and very obviously hand soldered. So at some point it's better to NOT automate, even if you have volume. Hmm.

I was watching various tear-downs of the Atten 858D+ heat gun when this occurred to me. You also see similar design approach in every cheapie power adapter.

What am I missing?

Just seems odd to me.

[marshallh]

Because they can get assembled for cents by kids in a chinese warehouse with chickens running around.

[mamalala]

What am I missing?

Commercial production in high quantities where everything is made down to a price vs. quality stuff where price isn't the first concern, or hobbyist stuff where you don't care anyways.

FR4 is more expensive than resin soaked cardboard. Single sided is cheaper than double sided. Wave soldering is relatively cheap and quick compared to reflow. (What you see with mass produced boards using  THT parts is usually wave soldered. And you can pick&place THT parts as well, there are machines for that).

Greetings,

Chris

[justanothercanuck]

I saw this video a while back...  The fails were on the SMD pads, and not the through-hole pads.

[djacobow]

OK, so I get that the board material can be much cheaper, but I think the parts, on the whole, must be more expensive, perhaps unless they are designing around what they find in old inventory auctions or something. And I get wave soldering can be cheap, but some of the boards I've seen, they don't look wave soldered. They have flux all over them, uneven blobs of solder. Or consider wires soldered into holes by hand rather than using a connector which would clearly be labor-saving for the cost of a few pennies. Recently, I've disassembled a handful of lamp dimmers from the likes of Lutron and others. They looked like utter crap.

I dunno, I guess the economics speak for themselves, it's just interesting to me. It's like if you're prototyping, you start with a 2 layer board and SMT or PTH. You might use some parts that are easier to work with, but not super-integrated because they come in "impossible" packages. Eventually, you find a market and redesign for manufacture. That BGA with all the bells and whistles is now in play, and you can pull off a bunch of other parts because of it. Now you design entirely SMT so the auto assembly machines can really hum.

Then... you start getting competition and you have to design down to commodity levels. And all of a sudden crap PTH is back in play.

I guess the difference is that this only works for low-integration simple things like basic power electronics. If you need a BGA, then you can't go this direction, but if you can find TH versions of everything you need, it becomes a viable approach.

Commercial production in high quantities where everything is made down to a price vs. quality stuff where price isn't the first concern, or hobbyist stuff where you don't care anyways.

FR4 is more expensive than resin soaked cardboard. Single sided is cheaper than double sided. Wave soldering is relatively cheap and quick compared to reflow. (What you see with mass produced boards using  THT parts is usually wave soldered. And you can pick&place THT parts as well, there are machines for that).

Greetings,

Chris

[djacobow]

Interesting, thanks for the share. It's funny, I often wonder about the benefits of copper fill. Sure, I'm told it makes manufacturing easier and saves etchant, etc. But I don't see the (hobbyist) board houses asking for more money for boards with less than x% copper coverage, so I have to ask myself if there is any risk at all to adding the copper fill, and if I want to take it! Generally, I do, but I choose rather enormous setbacks around traces for this reason.

I saw this video a while back...  The fails were on the SMD pads, and not the through-hole pads.

[mariush]

It took me about 20 minutes of google-fu but found the thread on this very same forum...

https://www.eevblog.com/forum/chat/is-this-the-industial-method-of-mass-soldering-or-cheapo-way/

First post, check the video ... that's why those cardboard pcbs are often ugly... because even the poorest equipped factories can do them..  reposting video here:

???4

[Stonent]

Because they can get assembled for cents by kids in a chinese warehouse with chickens running around.

Free fast food?

[dannyf]

What am I missing?

Substitution between capital and labor, two key elements to any production system.

[Kjelt]

yup there was a product that primary run on a very specific oscillation frequency and the western companies used expensive hardware to achieve this but the chinese products used standard transistors and capacitors.
The western company could due to price not compete and did not understand how the chinese could make this product within spec with standard cheap components which on it's own had more then 20% tolerance.
Then they visited the factory and found out, the components were all measured one by one by hand (more then 1000 kids day and night not in the city but in the country where there are no labor laws and inspection) and then sorted in to hundreds of different value labeled boxes. The full boxes were transported to the factory and for each production run two exact matching boxes were used.
There is more then one answer to any problem.

[T3sl4co1l]

Brings to mind...

If it's dumb, but it works... it ain't dumb.

[dannyf]

The full boxes were transported to the factory and for each production run two exact matching boxes were used.

You always hear those stories from people who don't know what's going on.

There is more then one answer to any problem.

There are more than one story to the same fact,

[GK]

What's wrong with chickens running around?

[zapta]

What's wrong with chickens running around?

They pick on the parts that fall on the floor.