Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Drop-in transformer mounting method

Drop-in transformer mounting method

Drop-in transformer mounting method

Hi everyone;

I need to learn how drop-in type switched mode transformers are being soldered in wave soldering process.

The specific application details are listed below:

* The application is slim product of lcd tv.
* Due to slim design, the power supply should also be slim !!
* The maximum component height on the pcb is 10mm.

Due to height limitation, the switched mode transformer should be mounted as drop-in style. This means you open the related area of the pcb and let transformer body to go inside the pcb area, so you would be able to use 12-13 mm of heigh for the component.

As using the wave soldering process, you should be able to prevent the transformer body to face the solder while passing through the wave soldering.

I think we should use a cap or something else to provide a mask for the open area of the pcb through which the transformer drops in.

I want to learn if there's a known method for this purpose.
Please see atached picture of one example.

Thank you.

RE: Drop-in transformer mounting method

I highly doubt any of those board are wave soldered.  One transformer was definitely done by hand (the black one in the lower left-hand corner), and the other were on SMD boards and likely done with IR reflow.

Dan - Owner

RE: Drop-in transformer mounting method

You're right about the left lower corner (black) one, it's hand made.
But the others are being wave soldered, not reflow.

I'm wondering that how the component body is protected from hot solder.

Thank you for your reply.

RE: Drop-in transformer mounting method

How do you know those others are being wave-soldered?

Wave soldering of SMD components is rarely done as the components get washed away with each wave... in rare cases, the components may be glued down before being sent to the wave machine.  In mixed component cases, the SMD parts are IR-flowed and the remaining components (usually through-hole edge connectors, etc.) are soldered by hand.

Dan - Owner

RE: Drop-in transformer mounting method

That is the perfect application for a selective soldering machine. And if its not hand soldered its done with the selective solder machine. Like a single point (or multipoint nozzle) mini-wave with an x-y-z cartesian type movement system.  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close