SMT prototyping/DIY reflow ovens

[mackrackit]

I may be doing it wrong..
I just use the temperature control that is on the oven with an oven thermometer (kitchen type) to monitor it. My oven also has a timer.

I set the temperature for around 350 F and the timer for 15 minutes. Place the boards in the cold oven. When the timer goes off I leave the board in the oven with the door closed. The slow cool down seems to have less oxidation than a fast cool down.

[ScaleRobotics]

I set the temperature for around 350 F and the timer for 15 minutes. Place the boards in the cold oven. When the timer goes off I leave the board in the oven with the door closed. The slow cool down seems to have less oxidation than a fast cool down.

Thanks Dave, I guess I could have saved some money then! Although I was making boards with rgb surface mount leds that are supposed to be pretty sensitive about being baked. Here is the profile for the solder I was using. They say optimum performance is below 5.5 minutes to peak temp, and show it in reflow zone for 75 seconds.



I notice most manufacturer's specs are quite short. Here is some info from Microchip.


But perhaps I am being too worried about cooldown. And just keeping the door closed would be more gradual cooling.

[dhouston]

I just use the temperature control that is on the oven with an oven thermometer (kitchen type) to monitor it. My oven also has a timer.

I use a small kitchen count-down timer. I have critical points marked on the temperature dial and make changes manually. Initially, I used temperature strips and a thermocouple but now just wing it as the manual methods seem adequate. The only problem I've had over hundreds of boards is with some large components (2.1mm power jack, RJ11 jacks, etc.) starting to deform. I now leave those for manual soldering. I usually have ~50in² of boards so just open the door after the brief soak at high temperature. My boards probably wouldn't meet ISO standards but none have exhibited problems.

I do use a stainless steel stencil for larger boards and for v-grooved small boards. It precisely controls paste thickness and I cannot recall a component misalignment with a stencil while manual paste application frequently results in misalignments that need manual resoldering.

I have a spinal cord injury that has paralyzed the fingers of my left hand. I use tweezers to place components. I design using 805 or larger components. I figure anyone should be able to do this if a one-armed geezer can handle it. I find it easier than manual soldering through-hole components.

[rsocor01]

Initially, I used temperature strips and a thermocouple but now just wing it as the manual methods seem adequate.

I think that using a non-contact infrared thermometer is the best way to control the temperature. Of course this is true if you don't want to spend thousands of dollars in a professional reflow oven. I bought this thermometer from Home Depot for under $30, and it works great!

http://www.homedepot.com/h_d1/N-5yc1...atalogId=10053

You aim the laser at the boards that you are "cooking" and it will tell you the temperature either in degrees Fahrenheit or Celsius. You can even see the difference in temperature at any given time between a metallic part in your board and a PCB non-metallic section in your board.

Robert

[kukata86]

http://www.kukata86.com/en/what-is-r...ven-controller