Dear sir`s i want to place one TBGA144 with DRS24 rework station i use many different profile but with near all of them in the ramp stage and reflow stage the balls of the BGA thrown away from the part and cause many short circuit under it and also many missing pad around it . i wonder if anyone could help me how to set AIR FLOW,TEMPERATURE & TIME in the ramp stage and reflow stage, also if any body could send me a document that could help me for giving different type of profile for placing different types of BGA it would be appreciated . Thanks
I have used the DRS24 for many years and have had similar problems with what you are talking about. I do not have any documents but I will tell you what I have seen. It sounds like an inconsistant collpse of the BGA. If one side of the BGA collpses first, it usually bridges. If the part is uneven, there are usually opens on the lifted side.
Preheat is important. Make sure your preheat is adequate and at the correct temperature before proceding with the profile. Chech your preheater plate for "hot spots" We found certain area's of the plate were hotter. Just make sure that part that you are working on is located over a consistant area. Make sure the correct nozzle is used. A larger nozzle may work but a nozzle that is too small will give you inconsistant results. Verify your temps and airflow. You want the BGA to come up to temperature slowly and consistanly. If the airflow is too high, it will not heat evenly. Air vac should have recommended temps and the air flow should be dependant on the nozzle size that you are using.
Contact Air Vac for recommended times and temps. They have alot of experience and may have the numbers that you need for this part (although this is also dependant on the PCB)