Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Reflow Profiling

Views: 4140

#78470

Reflow Profiling | 22 July, 2017

We normally do reflow profile on non-populated solder sample board. We do use some critical component like BGA and put thermal couple underneath. I need your expertise. How much will it drop in peak temperature when we will be running populated board? I believe about 3 degree C. But I like to hear from the experts.

reply »

#78471

Reflow Profiling | 22 July, 2017

It depends on the thermal mass of your assemblies (boards and components). Generally, if boards are small with few layers, the additional mass of components may have a significant impact on reducing the peak temperature. If boards are larger with solid ground and are thermally heavy, processing this assembly with parts should not impact the peak temperature significantly (maybe decrease of up to 5 degrees C).

reply »

#78472

Reflow Profiling | 24 July, 2017

This will depend on many factors: your reflow oven chamber size, your oven temperature controller, the speed of the conveyor, size and mass of your PCB, etc etc.

In practice you should adjust the profile for each case if you want to set in the optimal middle of your process window, or you can group similar boards and run them with one profile

We use Mistral 360 with glass top where you can "see" your process while board pass through the oven, you see when the paste dry, you see when the reflow starts, what is the time above liquid etc etc, and can adjust up or down with few degrees in each chamber to achieve what you want without using any profiler

reply »

#78488

Reflow Profiling | 25 July, 2017

"We use Mistral 360 with glass top where you can "see" your process while board pass through the oven, you see when the paste dry, you see when the reflow starts, what is the time above liquid etc etc, and can adjust up or down with few degrees in each chamber to achieve what you want without using any profiler"

Anything past attaching thermocouples and using a data logger is guessing.

reply »

#78494

Reflow Profiling | 25 July, 2017

This is easy experiment. Just run no populated PCB and that a populated one using the same spot for your thermo-couples. If you have a convection oven, you might be surprised how small this difference could be if not none. In some cases, I would expect to see even the opposite - having higher temp with the parts(this air circulates and sometimes the parts can hold it in certain sections and not let it escape that quick)

reply »

#78496

Reflow Profiling | 25 July, 2017

Thanks to everyone for the help.

reply »

reflow oven profiler

Reflow Oven