TEMPERATURE DISTRIBUTION

July 8, 2013 in REFLOW SOLDERING

This post is about temperature distribution in homemade reflow ovens.

When developing a reflow oven or simply transforming a toaster oven into a reflow oven we ofter have doubts about temperature uniformity. Will my new oven have an even temperature distribution which will allow me to solder bigger pcbs?.

We have made a simple experiment using one homemade reflow oven to see if the temperature was uniform.

Our test oven is a simple oven equipped with 5x 180W  infrared lamps evenly distributed. This distribution should allow to have already quite good heat distribution.

horno entero_low

lamparas distribucion_low

 

Our next step will be to distribute temperature sensors on the inside of the machine to be able to record their temperature at the same time.

DSC_0099

Now we can start soldering. We will repeat the soldering process two times to see how temperature distribution is inside the oven with and without an fan for forcing the air to move. For the results see the graphs below:

The sensors marked with a “B” are showing the temperature with ventilator

Graphique 4

So the effect is that the uniformity of the oven with fan is much better but the oven is much more slower and heat looses are much bigger.

So if you oven is not really powerfull and you can not upgrade it you will have problems when soldering as the heating ramps will be much more slower. Take that into account when building your oven.

On the other side your oven will have a much better temperature distribution inside when using a ventilator, even with ovens equipped with infrared lamps this effect is quite clear. My oven have lamps evenly distributed an even like that some parts of the oven are 20°C cooler than others.

UPDATE (10/12/2013): We have added more power to our oven, if you want to see the results go here.