Hello Friends! I am getting ready to reflow a triple Nichia mcpcb onto a copper spacer. This is for a convoy s3. I thought before I do, I would try and gain some knowledge from all of the experienced triple builders out there so here are just some questions I have:
Do you heat the spacer befor you put on the mcpcb or do you just heat it up all together?
How long do you keep heating after the melting temperature is reached? I will be using a home made hot plate and I do have a thermocouple to track the temperature.
How do you keep all of the emitters and copper jumpers from moving out of place? I would think they would stay there but wouldnāt they bubble up without being able to press down on all emitters when heat is removed.(like you would when reflo wing an emitter) I donāt even know if this makes sense?
Are there any tips or information that would be good for me to know before I do the reflow?
I use a blowtorch for this, usually about 10 seconds of heating is enough for a brass pill, maybe less for a copper spacer.
-Clean up the mcpcb and copper spacer surface, if copper is oxidized then polish it/ sand it with high grit paper.
-Apply an even thin layer of soldering paste and place the mcpcb
-Hit it with blowtorch from below
-As soon as the solder melts, remove heat and apply pressure on top with tweezers and align the mcpcb, keep it in place until it cools down.
As long as you donāt touch the LEDs they wonāt move. Personally I donāt like using heat guns or the hot plate method, sometimes it takes too long and the existing solder dries, making the LED connection weak. I recommend trying with any blank mcpcb first to know how long you should keep the blowtorch, just remember to remove the old solder before reflowing the real mcpcb.
Just be careful. The copper heatsink will suck up heat and retain it like a glowing ingot. The mcpcb will solder itself down, but that mini blast furnace of a heat sink will keep pumping out heat which can cause the entire mcpcb to go out of control and blacken and separate the dielectric layer from the noctigon.
roll up a piece of aluminium foil, like a tube and insert it in the center hole, it should be wide enough to stop horizontal moving of mcpcb but loose enough to allow vertical moving and you will have perfectly centered mcpcb.
This is very true. If you have compressed air you can use it to cool the heatsink down a little faster. Blow upwards from under the heatsink so you donāt blow the MCPCB off!
Iāve used a blowtorch for the soldering but the one I have sucks pretty bad, took for ages. Now I use the hot air soldering station at highest temp on full blast. Quicker than my crappy blowtorch and it saves me from having to buy a better one (and new gas).
Good to know. Iām using a homemade hotplate so it will probably work a bit differently than this. Its a block of 3ā aluminum round stock with a 1/2ā 100w soldering iron heater cartridge going through from the side. I have two of these blocks so, I plan to use one to cool the copper/mcpcb down after the solder melts. This is my plan anyway? I successfully did a sk68 pill with 5 pennies and a xml2 on 16mm sinkpad. This triple, however, has many more components so Iām gleaning advise before I give it a go. Which will be in the next few hours:)
Wellā¦ Itās done. Iām not sure if I used enough solder paste or not, but itās good and stuck I tried to record the episode, but I donāt know what it is about filming these events? Thereās always something to laugh at durring some part of the clip. Shaky hands, dropping things, dropping everything. Thereās also forgetting things, bumping things, and burning things-like yourself;) and thatās just me!!! :bigsmile:
So if I can figure out how to edit and make the video shorter from my iPad, I will post it and alow you to have a laugh at my expense.
Anywayā¦ I think it turned out ok? A couple of the jumpers shifted durring the process but other than that it all looks good. However, the jumpers that shifted are so close to each other that I donāt know how they are not touching? Iāve tested for continuity over and over and everything tests as it should. Maybe someone can let me know if it could be a problem?
Hereās what I do. I get a small container and put maybe an inch or two of water in there. As soon as the solder settles, I slowly immerse the whole bit in there, obviously taking care to not let the leds get wet. It will sizzle like crazy, but it cools the pill and spacer off very fast.
Also the last time I did a triple xpl reflow, the whole thing slipped and fell on the floor when I put pressure down from the top. The solder was wet, and everything separated when it contacted the floor. After collecting everything and reflowing it all back on, it worked fine!
Doing it this way is quite slow but I need every second I can get to think it all through. If I did it the quick way using a torch bad things would start to happen as soon as I saw flames;)
Well done, glad the slip didnāt cause any harm. Thanks for taking the time to make the video, I havenāt had the need to do this yet but itās on my radar. Any notes I can take ahead of time are worth more than than their weight in gold.
so here are just some questions I have:
I tried to record the episode, but I donāt know what it is about filming these events? Thereās always something to laugh at durring some part of the clip. Shaky hands, dropping things, dropping everything. Thereās also forgetting things, bumping things, and burning things-like yourself;) and thatās just me!!! :bigsmile:
