Topics

Reflow soldering multi-pin SMDs #eagle #pcbgcode


John Ferguson
 

I'm posting this question because there is so much good experience expressed in the posts here.

I have my new fixture completed with the .250 hdpe alignment pins and the alignment holes added to the drill jig and find it close to perfect,, slight press fit pushing the pcb down over the alignment pins and then secured with the 6-32 nylon socket head cap screws.  I made another jig plate 5 inches long with holes for  the two .250 alignment dowels.  one of the long sides is milled parallel with the dowels so that I can put it on the dowels and use the milled edge to align the fixture with the X-Axis of the mill.

It is as close as I can measure.

My second smd board after I make the trial board will contain a multi-pin GPS chip.  The contacts are on the bottom of opposite edges.  Assuming that I lay down the paste with a .004 stencil and it looks neat, and I place the chip carefully and accurately is there a real possibility that I will end up with bridges or other problems where I cannot see them?

If I do, what should I do then?

John ferguson


Jerry Lee Marcel
 

On Tue, Aug 25, 2020 at 03:57 PM, John Ferguson wrote:
My second smd board after I make the trial board will contain a multi-pin GPS chip.  The contacts are on the bottom of opposite edges. 
Do you mean something like a BGA?


John Ferguson
 

Not that bad.  the chip has little cylindrical hollow posts on opposite edges. They are cut away and I think would be easy to solder by hand.  Ive hand soldered earlier smd projects but in those cases the pins of the multi-pin chips projects horizontally and I was able to remove the bridges with copper braid.

john

On 8/25/20 10:10 AM, Jerry Lee Marcel wrote:
On Tue, Aug 25, 2020 at 03:57 PM, John Ferguson wrote:
My second smd board after I make the trial board will contain a multi-pin GPS chip.  The contacts are on the bottom of opposite edges. 
Do you mean something like a BGA?


John Ferguson
 


Jerry Lee Marcel
 

On Tue, Aug 25, 2020 at 04:28 PM, John Ferguson wrote:
This is what the chip looks like:


https://cdn-shop.adafruit.com/datasheets/GlobalTop-FGPMMOPA6H-Datasheet-V0A.pdf
OK. IINM, it's what they call "castellated" holes. Since they are plated through, soldering them should be even easier than usual SMD's because solder would tend to go up with capillarity.


Nick Quill
 

Hi John
I have a lot of experience of surface mount assembly in fact I have spent the last 20 years running an SMD assembly company.
If it was a production job we would use a 0.1mm stencil to apply paste and reflow with hot air convection reflow and would expect no issues with shorts etc.
To be honest these devices are very easy to hand solder if you use a fine cored solder wire and liquid flux.
If you align the device accurately on the pads and just solder opposite diagonal pads and then check alignment and make sure device is flat to the board before soldering the other connections. Would also recommend using lead based solder as it will flow much better. If the unit is for personal use and not being sold using tinlead is allowed.

On 25 Aug 2020, at 15:28, John Ferguson via groups.io <jferg977=aol.com@groups.io> wrote:

This is what the chip looks like:


https://cdn-shop.adafruit.com/datasheets/GlobalTop-FGPMMOPA6H-Datasheet-V0A.pdf




John Ferguson
 

Thanks Jerry,

It's good to know what these things are called. 

On 8/25/20 11:49 AM, Jerry Lee Marcel wrote:
On Tue, Aug 25, 2020 at 04:28 PM, John Ferguson wrote:
This is what the chip looks like:


https://cdn-shop.adafruit.com/datasheets/GlobalTop-FGPMMOPA6H-Datasheet-V0A.pdf
OK. IINM, it's what they call "castellated" holes. Since they are plated through, soldering them should be even easier than usual SMD's because solder would tend to go up with capillarity.


keith3125
 

Those are castallations. In my opinion the most easy to solder and by hand. I love those terminations

On Tuesday, August 25, 2020, 10:28:12 AM EDT, John Ferguson via groups.io <jferg977@...> wrote:



John Ferguson
 

I think I will do these by hand.  thanks for the recommendation.

On 8/25/20 5:11 PM, keith3125 via groups.io wrote:
Those are castallations. In my opinion the most easy to solder and by hand. I love those terminations

On Tuesday, August 25, 2020, 10:28:12 AM EDT, John Ferguson via groups.io <jferg977@...> wrote:




Ken McNabb
 

I’ve have been using ISM radio modules with these terminations for many years. If you board has a solder mask you should be ok with it. We tend to hand solder these due to some experience with modules failing after reflowing. (they are rated to be reflowed but the failure rate was considerably higher in our experience.)

One little tip I have, which will be possibly controversial to the purists, is we put a strip of magic tape down first. It will probably have a different name elsewhere in the world, possibly invisible tape etc.

This puts a tiny gap under the module of approx. 0.05mm. It helps two ways. Solder is less likely to bridge between pads, secondly if you ever need to remove the module you can with solder wick and a fine stainless blade.

Our units are fitted to vehicles and after more than 8 years we have not had any issues with failures in the field so it doesn’t seem to weaken the solder joints at all.

 

Regards

Ken

 

From: pcbgcode@groups.io <pcbgcode@groups.io> On Behalf Of John Ferguson via groups.io
Sent: Wednesday, 26 August 2020 7:12 AM
To: pcbgcode@groups.io
Subject: Re: [pcbgcode] Reflow soldering multi-pin SMDs #EAGLE #PCBGCODE

 

I think I will do these by hand.  thanks for the recommendation.

On 8/25/20 5:11 PM, keith3125 via groups.io wrote:

Those are castallations. In my opinion the most easy to solder and by hand. I love those terminations

 

On Tuesday, August 25, 2020, 10:28:12 AM EDT, John Ferguson via groups.io <jferg977@...> wrote:

 

 

 


keith3125
 

Pardon me for saying so but that sounds like a bad idea because you're relying on the solder to bridge that gap rather than heating the castellation so the chip doesn't misalign.
And that's called a possible 'head in pillow' in PCB jargon.

On Tuesday, August 25, 2020, 07:22:26 PM EDT, Ken McNabb <k.mcnabb@...> wrote:


I’ve have been using ISM radio modules with these terminations for many years. If you board has a solder mask you should be ok with it. We tend to hand solder these due to some experience with modules failing after reflowing. (they are rated to be reflowed but the failure rate was considerably higher in our experience.)

One little tip I have, which will be possibly controversial to the purists, is we put a strip of magic tape down first. It will probably have a different name elsewhere in the world, possibly invisible tape etc.

This puts a tiny gap under the module of approx. 0.05mm. It helps two ways. Solder is less likely to bridge between pads, secondly if you ever need to remove the module you can with solder wick and a fine stainless blade.

Our units are fitted to vehicles and after more than 8 years we have not had any issues with failures in the field so it doesn’t seem to weaken the solder joints at all.

 

Regards

Ken

 

From: pcbgcode@groups.io <pcbgcode@groups.io> On Behalf Of John Ferguson via groups.io
Sent: Wednesday, 26 August 2020 7:12 AM
To: pcbgcode@groups.io
Subject: Re: [pcbgcode] Reflow soldering multi-pin SMDs #EAGLE #PCBGCODE

 

I think I will do these by hand.  thanks for the recommendation.

On 8/25/20 5:11 PM, keith3125 via groups.io wrote:

Those are castallations. In my opinion the most easy to solder and by hand. I love those terminations

 

On Tuesday, August 25, 2020, 10:28:12 AM EDT, John Ferguson via groups.io <jferg977@...> wrote:

 

 

 


Ken McNabb
 

Yes it is only good for hand soldering where you can place the iron on both sides of the join. (tape is rated for reflow temps so should never be used there anyway). Familiar with the fault you mention. Our skilled hand soldering people know how to avoid it. Like I said after many years we have had no returns from hundreds of modules, from soldering faults. As I said the purists will not like this method, but we have found this reliable and if we do get a failed module, it makes it quick and easy to replace, without having to bust out the hot air tool and fit the special nozzle. While bridging on the production boards is typically not an issue, on the “machined” prototypes it seems to be more common. That said we rarely use “machined” boards these days, unless we are in a real hurry and can’t wait for the 10 days from the pcb fab.

 

From: pcbgcode@groups.io <pcbgcode@groups.io> On Behalf Of keith3125 via groups.io
Sent: Wednesday, 26 August 2020 10:26 AM
To: pcbgcode@groups.io
Subject: Re: [pcbgcode] Reflow soldering multi-pin SMDs #EAGLE #PCBGCODE

 

Pardon me for saying so but that sounds like a bad idea because you're relying on the solder to bridge that gap rather than heating the castellation so the chip doesn't misalign.

And that's called a possible 'head in pillow' in PCB jargon.

 

On Tuesday, August 25, 2020, 07:22:26 PM EDT, Ken McNabb <k.mcnabb@...> wrote:

 

 

I’ve have been using ISM radio modules with these terminations for many years. If you board has a solder mask you should be ok with it. We tend to hand solder these due to some experience with modules failing after reflowing. (they are rated to be reflowed but the failure rate was considerably higher in our experience.)

One little tip I have, which will be possibly controversial to the purists, is we put a strip of magic tape down first. It will probably have a different name elsewhere in the world, possibly invisible tape etc.

This puts a tiny gap under the module of approx. 0.05mm. It helps two ways. Solder is less likely to bridge between pads, secondly if you ever need to remove the module you can with solder wick and a fine stainless blade.

Our units are fitted to vehicles and after more than 8 years we have not had any issues with failures in the field so it doesn’t seem to weaken the solder joints at all.

 

Regards

Ken

 

From: pcbgcode@groups.io <pcbgcode@groups.io> On Behalf Of John Ferguson via groups.io
Sent: Wednesday, 26 August 2020 7:12 AM
To: pcbgcode@groups.io
Subject: Re: [pcbgcode] Reflow soldering multi-pin SMDs #EAGLE #PCBGCODE

 

I think I will do these by hand.  thanks for the recommendation.

On 8/25/20 5:11 PM, keith3125 via groups.io wrote:

Those are castallations. In my opinion the most easy to solder and by hand. I love those terminations

 

On Tuesday, August 25, 2020, 10:28:12 AM EDT, John Ferguson via groups.io <jferg977@...> wrote: