Tutorial: Do Surface Mount Boards

  1. Category
    How To, DIY
    Views
    33,119
    Replies
    5
     

    Do Surface Mount Boards

    Difficulty
    Medium/Hard
    Estimated Time
    One hour
    Skills Required
    Good eyesight, steady hands
    Parts Required
    PCB
    Surface mount components
    Solder paste
    Tools Required
    Reflow oven
    Fine tip tweezers
    Flat razor blade
    Isopropyl alcohol
    Laser cut stencil
    This tutorial will attempt to show (by example) how to do surface mount printed circuit boards. In this tutorial, I will show the steps required to build several of my Bioloid IMU boards.

    The first thing I do when I'm getting ready to do a set of boards (all the same) is to lay out all the parts on my workbench.

    Attachment 426

    In the image above, I've got (almost) all the parts lined up for making ten IMU boards. The parts that are scattered around are all 0603 sized 0.1 uF capacitors. Each IMU board required five of those parts, so I have 50 of them there.

    This next picture shows them stacked neatly - yes, it takes almost as long to lay out the components as it does to populate the boards! I also show some of the tools involved. The scissors and x-acto knife are for opening up the surface mount component rolls, and aren't actually used during the layout.

    Attachment 427

    Next, you can see the solder paste itself, plus the flat razor blade I use to spread the solder paste on the board. I've squeezed out a line of solder paste onto a piece of paper, and I scoop that up with the blade when I'm ready to start.

    Attachment 428

    This is the stencil. I get my stencils made at SMT Stencil, which is a web site run by the fine folks at Pololu. I send them a gerber file of my PCB layout, and they mail me back a piece of transparency with the holes all cut in the right place.

    Attachment 429

    Once the stencil is aligned with the board (which I do by eye), I grab the blade, and rub it across the stencil. The solder paste drops into the holes, and ends up sitting on the pads.

    Attachment 431

    After washing the solder paste off the stencil, the parts are then placed on the board, one at a time, using the tweezers. This part goes fairly quickly. Once all the parts are placed, it is ready to go into the reflow oven.

    Attachment 432

    Once I have five or six boards done, I place the tray (which is just a piece of aluminum with a thin sheet of silicone on top) into the oven, beneath the temperature probe from the oven controller.

    Attachment 434

    I switch on the oven, and wait five or six minutes for the reflow cycle to finish.

    Attachment 435

    Once the boards are done and have cooled down enough, I pull out the tray (using a pair of needle nosed pliers. I slide the boards onto my workbench, and check over each one to look for solder bridges on the chip(s).

    Attachment 436

    It takes two to three hours to build ten IMU boards like you see here...

    Attachment 437

    Once the surface mount parts are done, I solder on the through hole parts (mostly connectors), and program and test the boards.

    Here's a video showing the setup and board population:

    [YOUTUBE]z_NIY8GyQ90[/YOUTUBE]
    Attached Files
    • Parts-01
    • Parts-02
    • SolderPaste-01
    • Stencil-01
    • Stencil-Board-01
    • Paste-Board-01
    • BoardReadyToBake-01
    • FirstBatch-01
    • BoardsInOven-01
    • OvenControlBox-01
    • Boards-Done-01
    • Boards-Done-02
    "The best way to predict the future is to invent it." - Alan Kay, inventor of Smalltalk


Replies to Tutorial: Do Surface Mount Boards
  1. Join Date
    Dec 2007
    Location
    Portland, OR
    Posts
    3,198

    Re: Do Surface Mount Boards

    EXCELLENT work Jon! 10/10!
        

  2. Join Date
    Sep 2006
    Location
    Carol Stream, Illinois
    Posts
    1,695

    Re: Do Surface Mount Boards

    Great work Jon, thanks for the tutorial

    �In the long history of humankind (and animal kind, too) those who learned to collaborate and improvise most effectively have prevailed�
    - Charles Darwin
        

  3. Join Date
    Apr 2008
    Location
    Sacramento, CA, USA Area
    Posts
    5,341

    Re: Do Surface Mount Boards

    Hi Jon,

    Great work!

    Do you think it's worth talking about what a reflow oven is and where to find one (or maybe the option of a rework station for smaller batches) and also how you check your boards for cold solder (and do you, or do you just plug 'em in and exercise them before sending them out)?

    Thanks, Jon! This is great! I've been wanting to find the time for awhile to do a rework tutorial...
    I Void Warranties�
        

  4. Re: Do Surface Mount Boards

    I built my own reflow oven using a toaster oven and a controller made from an ATmega168...

    See this page from my blog for some of the details.
    "The best way to predict the future is to invent it." - Alan Kay, inventor of Smalltalk
        

  5. Join Date
    Apr 2008
    Location
    Sacramento, CA, USA Area
    Posts
    5,341

    Re: Do Surface Mount Boards

    That's too awesome! You should send that to Make Magazine!
    I Void Warranties�
        

Closed Tutorial