Soldering Irons - Ultra fine soldering

[ban-all-sheds]

Yes it is - in some cases it's considerably higher.

 

[aptsys]

I assumed "rework" meant manual soldering in the process of repairs...

It does

Err....

those SMT rework tips are for rework rather than soldering.

You use them for removing components. You wouldn't usually use them for soldering the components.

 

[IJWS15]

A warning for those who don't already know . . .

Some PCB components are not suitable for lead free solder - the higher temperature destroys them. Check with makers data sheets.

Made life interesting for our production people where you can only switch a board to lead free only when you have suitable components to replace everything on the board. One component holds up the whole changeover.

 

[ban-all-sheds]

You use them for removing components. You wouldn't usually use them for soldering the components.

What do you use to replace components?

 

[mattylad]

SMD "rework" includes manual soldering, otherwise how the heck do you put the component back once it has been removed?

You are simply redoing the work (hence "rework") that the SMT placement machines & ovens have done, on a small/local scale so that you do not need to put all the rest of the board & components back through the assembly process again.

A hot air rework station can easily be used to do the initial soldering on single/few SMD components, that IS one of the functions that it is designed for, soldering using hot air.

Whenever I need individual SMD components fitting to a prototype board, I simply take it to the shop floor and use the rework station, or if it's a complicated component I'm unfamiliar with I get one of the shop floor lasses to do it for me, but they still use the hot air rework stations.

(I have my own station but the compressor went walkies )

SMD components are designed to be soldered using either hot air or wave solder NOT soldering iron tips, especially the smaller/finer components that can easily be damaged by using iron tips.

Aptsys, what do you use to replace a component then? magic!

EDIT: Just to confirm, I'm talking about a hot air rework station like this although maybe not one that's so expensive - lol

 

[sm1thson]

using a flux pen helps loads, so does a clean tip (the chemical tip cleaners are handy), lead free solder is a pain to work with use lead where you can (and use thin solder not thick stuff), the 12w antex iron from maplin http://www.maplin.co.uk/Module.aspx?ModuleNo=4048 is great for smt resistors etc (generally down to 0603, 0402 with practice). hot air stations are good, but it takes time getting use to them for less complicated devices stick with an iron or you may just be overcomplcating things if you dont already have the tools and know how.

 

[ban-all-sheds]

Aptsys, what do you use to replace a component then? magic!

The oven of a Baby Belling?

 

[mattylad]

Isn't that for melting cheese?

The problem with putting the whole board back through an oven is that you can introduce new problems & bad joints on other components when they all reflow again, which is why there are hot air rework stations for local working.

 

[aptsys]

You use them for removing components. You wouldn't usually use them for soldering the components.

What do you use to replace components?

Hot air or soldering iron usually. Some of those desoldering bits don't allow any means of holding the component down or even locating the component.

 

[mattylad]

Hot air?
Not from a hot air rework station by chance? lol

 

[meditatinghamster]

Is the melting temperature of lead free solder higher than the old lead/tin solder? If so, that would explain difficulties when trying to desolder using a conventional iron on newer boards.

Regards

From what I can see, the lead free ones melt at a higher tempperature.
"common alloys are 60/40 Sn/Pb which melts at 370 °F or 188 °C and 63/37 Sn/Pb used principally in electrical work"

Although I did encounter some magical solder that wouldn't melt even at 400+.
I was trying to replace a transistor (the regular biggies) on a motherboard. Two of the legs would desolder, but one of them just would not melt no matter how high the temperature of the iron. Surreal, lol.

http://en.wikipedia.org/wiki/Solder#Lead_solder