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[chookey]

I see what you mean now Rob. Clearly visible on my board.How are they cleaned after process, ultrasonic bath?

Edit
Wonder if Air Digital would recognise this board as one that slipped through the net

 

[Spectre]

I see what you mean now Rob. Clearly visible on my board.How are they cleaned after process, ultrasonic bath?

I sometimes don't explain stuff too explicitly as I don't want to seem condescending to experienced people, such as yourself . Useful to new people though.

Nowadays PCBAs are not usually cleaned at all. The flux (wave solder machine) is put on by sprays on a machine of that capacity (bubble bar on really small machines) and should mostly be gone after going over the solder wave(s). It could even be that the spray pressure isn't correctly regulated and the flux got blasted between the pallet and the board. I know the SEHO 8240 was prone to flux sprayer mishaps due to magnetically coupled impellers where flux deposition could vary wildly . That was quite specific however .

I just pulled a work prototype PCBA out (I twiddle with stuff at home) but it was soldered in a "finger pallet" and so didn't have any halos around the pins to get a picture.

If they used a more aggressive flux due to the low solderability of some of their components it might be more difficult to remove and nobody (maybe apart from space and aviation) wash their PCBAs any more.

 

[cactikid]

I see what you mean now Rob. Clearly visible on my board.How are they cleaned after process, ultrasonic bath?

Edit
Wonder if Air Digital would recognise this board as one that slipped through the net

What about all the others in that batch,how many in a batch?

 

[chookey]

I sometimes don't explain stuff too explicitly as I don't want to seem condescending to experienced people, such as yourself . Useful to new people though.

Nowadays PCBAs are not usually cleaned at all. The flux (wave solder machine) is put on by sprays on a machine of that capacity (bubble bar on really small machines) and should mostly be gone after going over the solder wave(s). It could even be that the spray pressure isn't correctly regulated and the flux got blasted between the pallet and the board. I know the SEHO 8240 was prone to flux sprayer mishaps due to magnetically coupled impellers where flux deposition could vary wildly . That was quite specific however .

I just pulled a work prototype PCBA out (I twiddle with stuff at home) but it was soldered in a "finger pallet" and so didn't have any halos around the pins to get a picture.

If they used a more aggressive flux due to the low solderability of some of their components it might be more difficult to remove and nobody (maybe apart from space and aviation) wash their PCBAs any more.

I'm experienced in the service/ repair sector, not production so it's good for me to know as well. I should have guessed that tbh as I normally can evaporate the majority of my flux during the reflow process. I still clean my boards after repair and test though, more habit than anything else.

If the Zgemma had cost more I would probably contact Air Digital and point out this fairly obvious production fault. May not have got me anywhere but would have been nice to see their reply if any.

 

[cactikid]

Who thinks of safety when buying cheap and what might happen.



.memo to self buy batteries for smoke alarms

 

[Spectre]

I'm experienced in the service/ repair sector, not production so it's good for me to know as well. I should have guessed that tbh as I normally can evaporate the majority of my flux during the reflow process. I still clean my boards after repair and test though, more habit than anything else.

If the Zgemma had cost more I would probably contact Air Digital and point out this fairly obvious production fault. May not have got me anywhere but would have been nice to see their reply if any.

In service or repair you have to be careful with other people's stuff, I can (currently) bash the stuff I have about a bit . I'm exaggerating a bit there, I'm careful, but the stuff I usually work with have larger scale components (minimum 0402 at present, I think) than consumer products. There are restrictions on pin pitch and BGA ball pitch also so we have to go through special component introduction processes for anything else!

I had a few technician level jobs before I went to university (full time, being paid for by myself! Not even a grant, all loans!) . A couple were in process control involving soldering because I accrued the training levels quite fast (once was interviewed by a large company for the job of "soldering trainer" but it wasn't really what I wanted and I think it showed).

Soldering sounds so benign but it's an important and difficult-to-monitor process. My background is still called upon in my current job for advice reasons but things are moving on.

Going to bore people to death here but...

One of the things I have noticed is that due to the density requirement, toe fillets are disappearing from chip-style SMT footprints. They rely on the solder sandwiched between the cap and the pad or a heel fillet (which are limited due to not wanting stencilled solder encroaching too far back and the cap itself). Rather than mechanical, hot-air is the next choice.

Unreworkable isn't too bad for me as I'm sure some people are just making up that they "can't see"!

 

[cactikid]

Hot air as you were eating baked beans again?

 

[Spectre]

Hot air as you were eating baked beans again?

Only Weller brand baked beans though .

 

[Spectre]

What about all the others in that batch,how many in a batch?

Forgot about a reply to this post, sorry about that! I'm probably a bit behind the times but here's some stuff that I used to know and have seen about twenty years ago .

A pallet in a normal capacity machine would be able to carry two 20cm x 20cm sized boards or one computer full-sized mainboard. Beyond that, special supports and whatnot are needed to stop the board sagging when it hits the wave (in a THT waver soldering process).

The typical cycle (wave) time from pallet going into machine to exiting would be about six minutes with preheating time, wave and the cool down. A lot depends on the board itself and a 12-layer board with copper ground pours on all layers will take longer to solder than a 4-layer board with a power and ground plane and two routing layers (with ground pour on all layers).

So... A batch is probably two for that size board and there would be possibly five pallets in a wave machine at any time.

 

[cactikid]

I think i read many years ago about boxes stored under leaky roof that got damp and got shipped out and thinking how many might that have been,some expensive stuff come with a pack of moisture absorbing granules.