As you can see from these photos, I'm having a hard time applying solder to pads for QFN parts with 0.5mm and below pad sizes. The stencil is 5mm thick, hence the pile.
If I were to placed a component on these pads and use my re-flow oven, I will surly get bridging.
And help would be greatly appreciated.
Problems applying the right amount of Solder Paste
Moderators: adafruit_support_bill, adafruit
Please be positive and constructive with your questions and comments.
- jamesbuchanan1220
- Posts: 13
- Joined: Mon May 26, 2014 2:07 am
- Franklin97355
- Posts: 23912
- Joined: Mon Apr 21, 2008 2:33 pm
Re: Problems applying the right amount of Solder Paste
Not a lot you can change if you can't get the proper stencil.
- jamesbuchanan1220
- Posts: 13
- Joined: Mon May 26, 2014 2:07 am
Re: Problems applying the right amount of Solder Paste
What is the proper stencil?
- Franklin97355
- Posts: 23912
- Joined: Mon Apr 21, 2008 2:33 pm
Re: Problems applying the right amount of Solder Paste
One that has the proper thickness for the pitch of the pads on the PCB.
- jamesbuchanan1220
- Posts: 13
- Joined: Mon May 26, 2014 2:07 am
Re: Problems applying the right amount of Solder Paste
This is the thickness suggested. There must be something else.
- Franklin97355
- Posts: 23912
- Joined: Mon Apr 21, 2008 2:33 pm
Re: Problems applying the right amount of Solder Paste
Then you are not holding the stencil to the board tight or squeegeeing hard enough.
- jamesbuchanan1220
- Posts: 13
- Joined: Mon May 26, 2014 2:07 am
Re: Problems applying the right amount of Solder Paste
Notice the surrounding pads, you'll see that this problem does not happen to the other pads. Have you ever used a stencil?
- jamesbuchanan1220
- Posts: 13
- Joined: Mon May 26, 2014 2:07 am
Re: Problems applying the right amount of Solder Paste
To be fair, these pads are associated to DFN type parts. Thus, less than 1 mm on each pads dimensions and from the configuration of the pads, not possible to hand solder; since the pads are under the part's body.
- Franklin97355
- Posts: 23912
- Joined: Mon Apr 21, 2008 2:33 pm
Re: Problems applying the right amount of Solder Paste
I'm out of ideas then.
- juku
- Posts: 6
- Joined: Sat Sep 01, 2012 4:38 am
Re: Problems applying the right amount of Solder Paste
SMD stencils are typically 0.1mm thick.
- jamesbuchanan1220
- Posts: 13
- Joined: Mon May 26, 2014 2:07 am
Re: Problems applying the right amount of Solder Paste
Where do you get 0.1mm thick stencils?
- adafruit_support_mike
- Posts: 67454
- Joined: Thu Feb 11, 2010 2:51 pm
Re: Problems applying the right amount of Solder Paste
There are several companies online that will make them for you, but they run about $30-$40 per stencil.
- jamesbuchanan1220
- Posts: 13
- Joined: Mon May 26, 2014 2:07 am
Re: Problems applying the right amount of Solder Paste
So far, only 3mil is available. Again, which company does less then 1mm?
- juku
- Posts: 6
- Joined: Sat Sep 01, 2012 4:38 am
Re: Problems applying the right amount of Solder Paste
Some links in this thread: http://www.liteplacer.com/phpBB/viewtopic.php?f=8&t=83
- jamesbuchanan1220
- Posts: 13
- Joined: Mon May 26, 2014 2:07 am
Re: Problems applying the right amount of Solder Paste
Thank you, I'll look into them.
Please be positive and constructive with your questions and comments.