Removing IC with rework station but when to grab tweezers?

[komatsu]

I am going to be removing an IC from a hard drive PCB using a hot-air rework station.

I've looked at You Tube video's but I am a bit of unsure as to the exact moment you know when the
connectors have melted and it is time to grab a tweezers?

Any tips or advice would be great?

 

[komatsu]

Anybody?

 

[davenn]

The rework station I used had a suction cup that would lift the IC as the solder melted

 

[elebish]

I am going to be removing an IC from a hard drive PCB using a hot-air rework station.

I've looked at You Tube video's but I am a bit of unsure as to the exact moment you know when the
connectors have melted and it is time to grab a tweezers?

Any tips or advice would be great?

Flux the ic first and then heat. The solder will melt at approx. 419 degrees at which time the ic will "float" on the solder pads. Slightly bump the ic and it will move, ready to be lifted. Be careful not to heat too long or you may burn the board.

 

[shrtrnd]

As suggested, if you do this often, you might want to find a tool that lifts when the component is free.
Different solders melt at different temperatures, and we don't know the temperature your work station is operating at.

 

[mursal]

Has been known for people to lift one side, then the other side. This will allow you to heat/work one row of pins lift them free, then the other row. The pins will need a fettle when on the bench, but no big deal.

 

[elebish]

As suggested, if you do this often, you might want to find a tool that lifts when the component is free.
Different solders melt at different temperatures, and we don't know the temperature your work station is operating at.

Generally, solder paste that melts at a low 419 degrees is used for populating an sm board so as to keep the heat as low as possible. There are 2 different types of machines that are used to mount sm devices. One is a vapor phase and the other is an ir wave. Typically, the board is preheated for 15 seconds then lowered to the 419 degree chamber for 15 seconds, then raised back to the 200 degree chamber for cooling then back to the position where the board was initially installed to cool down so the board can be removed. Double sided component boards have the underside soldered first and those components are small and lighter than the major components on the top side which are soldered last. Solder wicking action keeps the smaller components on the bottom from falling off during the soldering of the top side components. A hot plate for preheating the board can be used during removal of a single smd along with a heat gun with a slow blower and an ss tweezer. Liquid flux made by MM is the best for solder flow when heating the component for removal.