Feasible with soldering iron?
I think my eyes and steady hand should make it just about possible. The pcb i have for an LT3045 has vias under the pad of the chip through to a pad on the reverse side of the board, so if I tin the u underside of the chip, I would imagine I can heat through from the reverse of the board through the vias to flow the solder to the base of the chip for heat dispersion?
Any thoughts
I think my eyes and steady hand should make it just about possible. The pcb i have for an LT3045 has vias under the pad of the chip through to a pad on the reverse side of the board, so if I tin the u underside of the chip, I would imagine I can heat through from the reverse of the board through the vias to flow the solder to the base of the chip for heat dispersion?
Any thoughts
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I use my Infra Red rework station and hot air to remove and re-ball all sizes of processors and simple SMD chips.
Use plenty of flux to increase the heat flow.
Use plenty of flux to increase the heat flow.
You will need to use a decent sized chisel tip as the PCB pads and LT3045 will wick heat away from the soldering iron tip.
Tin the pcb pad first but don't use too much solder then heat the bottom side of the board and place the LT3045 on the pad and wait for the solder to melt then gently push down so the LT3045 is flush on the PCB making sure the rest of the pads line up.
Tin the pcb pad first but don't use too much solder then heat the bottom side of the board and place the LT3045 on the pad and wait for the solder to melt then gently push down so the LT3045 is flush on the PCB making sure the rest of the pads line up.
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More flux, less solder is a good mantra for SMT work. Avoid touching the chip pins too.
My homemade reflow oven is a somewhat modified cheap sandwich toaster and the results are excellent compared to anything I can do by hand.
My homemade reflow oven is a somewhat modified cheap sandwich toaster and the results are excellent compared to anything I can do by hand.
Very neat, and I like the marks of the power polarity - saves confusion later on.
Actually, I was looking to see how you built your diy oven, so I could follow on - photos maybe, with a temperature control?
Actually, I was looking to see how you built your diy oven, so I could follow on - photos maybe, with a temperature control?
I think I'd have to open it up - the jist is I didn't bother with measuring temperarure as it came with a tmeperature control (of sorts), so my thermal profiles are very simple, start at 150C setting for 3 minutes, ramp up till the solder paste reflows.
It came with one top element and one bottom element, and I repositioned the top element, and moved the bottom beside it for a more even heating.
The temperature control is basically a PWM controller implemented with a self-heated trimetalic strip! It cycles every20 seconds or so, but this seems to work quite well (repeatably) as experiments have shown.
Solder stencils are invaluable for this kind of work, and I often cut my own with a laser cutter (I tried mylar sheet, but it raises edges, standard printer paper works though for one-time use).
It came with one top element and one bottom element, and I repositioned the top element, and moved the bottom beside it for a more even heating.
The temperature control is basically a PWM controller implemented with a self-heated trimetalic strip! It cycles every20 seconds or so, but this seems to work quite well (repeatably) as experiments have shown.
Solder stencils are invaluable for this kind of work, and I often cut my own with a laser cutter (I tried mylar sheet, but it raises edges, standard printer paper works though for one-time use).
I went out and found one of those oven/grill benchtop 'things' - found a small 9 litre 1200W unit with temp control - and now collecting some 'scrap' smd devices and spare boards and flux, solder, laser temp gun, stamp collectors magnifiers, a good light, etc to learn how to do this smd devices.
Apart from some practice, a lot of patience with these rather small objects, are there any special techniques required ….?
Apart from some practice, a lot of patience with these rather small objects, are there any special techniques required ….?
Have a look at just about any IC data sheet and you'll find the recommended temperature profile. It's worthwhile to do a little characterization of your oven to see which settings come closest to the recommended profile. You don't want to stress the components and the board more than necessary.
Tom
Tom
All the profiles are basically the same, soak for 2 or 3 minutes, ramp up, ramp down. If they weren't all the same you couldn't put different parts on the same pcb!
Well, in truth some parts are more fussy (melt quicker) - I've had flat-flex connector gates that melted (I think they prefer hot air heating to radiant).
Well, in truth some parts are more fussy (melt quicker) - I've had flat-flex connector gates that melted (I think they prefer hot air heating to radiant).