process_reflowoven

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Table of Contents

  1. What is a reflow oven?
  2. How to use the reflow oven

What is a reflow oven?

A reflow oven is a specially-designed temperature-controlled box with air circulation that is used for melting solder paste. In layman's terms, it's a precision oven that you don't put food into. The heating and cooling follow a relatively precise profile to melt the solder without causing too much thermal stress to the substrate and the components. The solder used here is actually solder paste, rather than standard solder wire, which is solder that's suspended in a flux paste. You apply this to the pads (typically using a stencil), place your components onto the board, and then put the board into the oven, which melts the solder paste and electrically adheres the components to the board.


How to use the reflow oven

The Hive's reflow oven, the LPKF ProtoFlow , is located in the Semi-Clean room on the lower level of the IDC in Van Leer. It looks like a large rectangular box in the far corner of the room. It's connected to a computer that can theoretically provide higher-precision information and control over the oven, but that's beyond the scope of this writeup. Feel free to experiment if you'd like.

The oven has a power button on the front of the tool, and a small screen with four arrow keys on the top. That's it.

To operate (images below):

  1. Make sure that your board is populated with solder paste and components prior to starting the oven. Do not place any soft plastic components such as connectors onto the board because they will likely melt in the oven! If you're concerned, check with the datasheets about their maximum storage temperature/maximum reflow temperature. The lead-free profiles will reach 290C.
  2. Power on the oven by pressing the power button on the front of the tool.
  3. Using the arrow keys and the screen, navigate to the profile you'd like to run.
    1. If you used lead-free solder paste like was recommended in the stencil write-up, “LF-MEDIUM” will be fine. The difference between sizes and between LF vs. LF-2 is unclear.
    2. If you used a leaded solder paste, you can try the “PB-MEDIUM” profile, but YMMV.
  4. Press the right arrow key to select the profile, and then the up arrow key to highlight “OPEN/CLOSE”. Press the right arrow key to open the drawer.
  5. Once the drawer is open, adjust the metal bars inside (they're magnetic) to be the correct spacing so that your PCB sits on their edges safely. When that's done, remove your PCB and press the right arrow key to close the drawer.
  6. Navigate to “START PROF” (down arrow key), and then start the profile with the right arrow key.
  7. Once the oven has warmed up (a minute or two), the drawer will open. Place your PCB onto the pre-aligned bars. BE CAREFUL - it's hot! Press the right arrow key to close the drawer.
  8. The profile will run.
  9. When it's completed, the drawer will open again. Carefully remove your PCB (it's hot!), and press enter to shut the drawer.

Clockwise from top-left: the oven with its computer; the drawer open with the magnetic metal bars; the front of the oven with the power button prominently featured; and the screen and the four arrow keys on top of the oven.

  • process_reflowoven.1649612667.txt.gz
  • Last modified: 2022/04/10 13:44
  • by benh