Notifications
Clear all

Cooking the books (I mean Hardware) Baking Components

14 Posts
4 Users
12 Likes
243 Views
Dazza
(@dazza)
Trusted Member
Joined: 3 months ago
Posts: 48
Topic starter  

I'm excited to receive my ESP32 chips from Digi-key

I am however at a loss about the Warning on the Packaging

SCS Moisture Barrier Bag DRI-SHIELD 3400

This bag Contains Moister Sensitive devices | 419 | T1 <- Highlighted in Yellow

The Stickers says Sealed: 26 Nov 2022

PPBT: N/A

ROHS3 COMP | MSL 3 -168 hours | 1 Day

Does anyone have any experience with this?

I'm not in a high humidity area, and temps in the house are about 15c - 25c (60f - 75f roughly)

I searched the Forums for BAKING, no matching results

This One, a long time I have I watched. All this life has he looked away to future, to the horizon. Never his Mind on where he was! what he was doing!
Yoda


   
Quote
Ron
 Ron
(@zander)
Famed Member
Joined: 2 years ago
Posts: 3915
 

@dazza Probably due to some idjit in California.

Arduino says and I agree, in general, the const keyword is preferred for defining constants and should be used instead of #define
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon
My experience hours are >75,000 and I stopped counting in 2004.
Major Languages - 360 Macro Assembler, Intel Assembler, PLI/1, Pascal, C plus numerous job control and scripting


   
JoeLyddon reacted
ReplyQuote
DaveE
(@davee)
Prominent Member
Joined: 2 years ago
Posts: 788
 

Hi @dazza and Ron @dazza,

  Humidity is a problem with surface mount components in general.

Although the plastics and ceramics packaged components are not obviously 'sponge-like', they can still absorb a certain amount of water from the general atmosphere.

During the soldering process, any water absorbed into the package will be turned into vapour, which can be sufficient to move the components, resulting in them not being soldered correctly. Alternatively, the pressure build up can crack the package.

Hence, if components have been exposed to air with 'normal atmospheric' humidity levels for more than a few hours, it is advised to 'carefully' bake them for an extended period, to expel the water, before soldering them onto a board.

Of course, these procedures are all written in the context of large scale manufacture, where a very small percentage of failures can still be very expensive, and in the case of safety related equipment, an increased failure rate may result in avoidable catastrophic events.

----------

If you are only making a one or a few units, for an application that can tolerate an unexpected breakdown, you may decide that the risks of such failure mechanisms are sufficiently low, that you can ignore them.That is your judgement.

However, as you are using a '1st grade' distributor, you should expect that they will look after your interests to the highest standards -- hence, they are providing information regarding the handling -- all part of the "Very Important Customer" service!

Best wishes, Dave


   
Dazza reacted
ReplyQuote
Dazza
(@dazza)
Trusted Member
Joined: 3 months ago
Posts: 48
Topic starter  

@davee Have you had any issues with your electronics? 

I'm looking at my Dev kit that is exposed to the atmosphere for near 1 month

These SMD ESP32 chips have been attached to the external PCB Antennae, I would Assume that it is safe to open 

This One, a long time I have I watched. All this life has he looked away to future, to the horizon. Never his Mind on where he was! what he was doing!
Yoda


   
ReplyQuote
Ron
 Ron
(@zander)
Famed Member
Joined: 2 years ago
Posts: 3915
 

@dazza I have an esp32cam that is exposed to the outside but under rain cover and it has been there for about a year with no problems yet.

Arduino says and I agree, in general, the const keyword is preferred for defining constants and should be used instead of #define
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon
My experience hours are >75,000 and I stopped counting in 2004.
Major Languages - 360 Macro Assembler, Intel Assembler, PLI/1, Pascal, C plus numerous job control and scripting


   
ReplyQuote
DaveE
(@davee)
Prominent Member
Joined: 2 years ago
Posts: 788
 

Hi @dazza,

re: Have you had any issues with your electronics? 

  Not yet .. but I don't claim to have a massive amount of personal experience in this area ...

I was just trying to explain why your package had the warning .. it is the result of 'standard' handling procedures for equipment aimed for  safety critical areas for several years, and companies like Digi-Key would help to supply such customers, so they must adopt appropriate procedures which meet the highest standards.

If you buy cheap parts from the well known bazaars, you will probably receive components stuffed in an ordinary plastic bag .. and most of the parts will probably work ... some won't, but hopefully none that have been treated carelessly will be used for products  whose failure could be catastrophic.

If you are making a one-off prototype for our own 'amusement', the chances of you seeing a problem is very small ... but if a close relative of yours was seriously injured because a piece of equipment had failed because the manfacturer had not taken all reasonable and expected precautions, I suspect your sympathy would not be with the manufacturer.

Similarly, manufacturers producing vast quantities of products such as mobile phones need to take every precaution, as an even a very small percentage of failed product that you are making a million off per week, can quickly turn into a mountain of products that either failed the factory inspection tests, or worse get returned by disgruntled customers. Repairing even minor faults on that scale is very expensive.

---------

As a note to the point from Ron "@dazza I have an esp32cam that is exposed to the outside but under rain cover and it has been there for about a year with no problems yet."

The humidity concern is about problems when surface mount components are soldered onto the boards, as the absorbed water can disrupt the soldering process, as the high temperature needed to melt the solder almost explosively turns into water vapour, when it can split component packages and cause small components to be physically moved off the pads it was supposed to be soldered to.

It is NOT about deterioration in service, although obviously damp conditions can cause their own problems, and precautions to seal the boards and components are often employed for boards that are subjected to high humidity environments.

------------------

Hope this helps .. your board should be fine ... Best wishes, Dave

 


   
Dazza reacted
ReplyQuote
Dazza
(@dazza)
Trusted Member
Joined: 3 months ago
Posts: 48
Topic starter  

@davee 

, and precautions to seal the boards and components are often employed for boards that are subjected to high humidity environments.

Is this the poors man's version of using Hot glue to seal in ICs? 

This One, a long time I have I watched. All this life has he looked away to future, to the horizon. Never his Mind on where he was! what he was doing!
Yoda


   
ReplyQuote
DaveE
(@davee)
Prominent Member
Joined: 2 years ago
Posts: 788
 

Hi @dazza,

  That was not what I had in mind...

Instead, I was thinking of what is usually called conformal coating.

In the more common form, it looks like the board has been dipped or sprayed with a "plasticy" varnish ... there are also more 'extreme' versions such as parylene which is put on in the vapour (gas) phase, so that is able to completely surround components, even when they are touching the board, making it difficult for a liquid to flow round.

If you ever have to modify or repair a circuit board with conformal coating, you will remember the pleasures of having to scrape through it to get a meter probe connection or to solder a new component into position. 🤨 🤨 

See Wikipedia for a bit more description: https://en.wikipedia.org/wiki/Conformal_coating

Probably much more than the average amateur needs to know ... but it might be a useful introduction to you in a wider context.

Best wishes, Dave


   
Dazza reacted
ReplyQuote
Will
 Will
(@will)
Famed Member
Joined: 2 years ago
Posts: 2218
 

Posted by: @dazza

@davee 

, and precautions to seal the boards and components are often employed for boards that are subjected to high humidity environments.

Is this the poors man's version of using Hot glue to seal in ICs? 

I strongly suggest that you use clear nail polish instead of hot glue for "waterproofing".

 

Experience is what you get when you don't get what you want.


   
Dazza reacted
ReplyQuote
DaveE
(@davee)
Prominent Member
Joined: 2 years ago
Posts: 788
 

@will et al,

  re: I strongly suggest that you use clear nail polish instead of hot glue for "waterproofing".

I haven't tried any 'poor man's conformal coating' .. so I can only ponder the options...

I agree hot glue could have downsides, though it usually melts at a reasonably low temperature, compared to soldering, etc. so if you could get it watertight, it might work as an encapsulant in (say) a small volume plastic box.

Nail varnish would be easier to remove for repairs, and no temperature concerns, but the acetone solvent might attack some plastic packages.

Engineering always seems to be a case of minimising the downsides ... 🤨 🤨 

And please remember the question was about baking components BEFORE soldering, not to encourage the resulting system to keep soldiering on in a damp environment. (pun intended, even if it was poor one. 🤭 )

Best wishes, Dave


   
Inst-Tech and Dazza reacted
ReplyQuote
Ron
 Ron
(@zander)
Famed Member
Joined: 2 years ago
Posts: 3915
 

@will Ok, I will bite. Why 'strongly suggest' clear nail polish? And what is wrong with Hot Glue?

Arduino says and I agree, in general, the const keyword is preferred for defining constants and should be used instead of #define
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon
My experience hours are >75,000 and I stopped counting in 2004.
Major Languages - 360 Macro Assembler, Intel Assembler, PLI/1, Pascal, C plus numerous job control and scripting


   
Dazza reacted
ReplyQuote
Will
 Will
(@will)
Famed Member
Joined: 2 years ago
Posts: 2218
 

Posted by: @zander

And what is wrong with Hot Glue?

I find hot glue less than satisfactory because it does not cover sharp edges well (like the corners and edges of PCBs) and unless applied to a squeaky clean surface may leave small fissures between the PCB and the glue which will allow the ingress of water. Also, when you finally get the top coated and turn it over to get to the bottom, the glue doesn't necessarily melt the glue from the top to make an impervious seal.

I've found that cheap nail polish eliminates most of these problems. Indeed, ou can come back a day later and cover the opposite side with excellent sealing of the overlapped are.

And to cap it all off, you can see through the nail polish, so you don't have to scrape off the hot glue to see if your solder joints are corrupted or your tracks are de-laminating.

 

Experience is what you get when you don't get what you want.


   
Dazza, huckOhio and DaveE reacted
ReplyQuote
Ron
 Ron
(@zander)
Famed Member
Joined: 2 years ago
Posts: 3915
 

@will I knew you had to have a very good reason, thanks for the detailed answer.

Arduino says and I agree, in general, the const keyword is preferred for defining constants and should be used instead of #define
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon
My experience hours are >75,000 and I stopped counting in 2004.
Major Languages - 360 Macro Assembler, Intel Assembler, PLI/1, Pascal, C plus numerous job control and scripting


   
Dazza reacted
ReplyQuote
Dazza
(@dazza)
Trusted Member
Joined: 3 months ago
Posts: 48
Topic starter  

You are right of course; I have seen Hot Glue used extensivity in hobbyist projects and cheap toys. I thought it was the norm.

Nail Polish makes perfect sense

This One, a long time I have I watched. All this life has he looked away to future, to the horizon. Never his Mind on where he was! what he was doing!
Yoda


   
ReplyQuote