First look at Nichia 119D D340 sm505 R70

clemence · February 18, 2019, 5:06pm

led4power:

clemence:

led4power:

IMO, any low melting point temp solder is not as good as it sounds, because diffusion of solder alloy atoms into soldering metal surface is greatly reduced compared to lead-free solder (diffusion increases exponentially with temperature). I’ve used some BiSn ~150C solder for prototyping before, and mechanically it sucks compared to PbSn, let alone SnAgCu. After soldering I can rip off components with relatively low force, basically every joint becomes like a cold joint, it’s more like a weak glue than like a solder.

I suspect the low diffusion could be also bad for metal-to-metal “contact” thermal conductivity, indium has slightly higher thermal conductivity than Pb-free SnAg solder, but thermal conductivities are given for bare metals only.

I don’t know what happens at boundary of solder alloy-base metal regarding the thermal conductivity, but my intuition tells me higher temp. solder would perform better even if it has slightly lower thermal conductivity because diffusion of atoms is better/deeper.

Sn52Ag48 is indeed sucks for LED soldering. I only use it for LED wires attachment to make soldering my boards (and those like yours too) easier. But preparing a low temp soldering blob for users is not as simple as it might look. Sn52Bi48 is very brittle as itself and not a good choice unless mixed with a little bit Pb based solder. To get a proper mix without leaving unmelted 60/40 or 63/37 granules, you have to heat it to slightly above the melting temp of the highest melting point of the contents. I’ll consider your explanation here for my next test. I can’t comment anything about it yet, have to go back to the classroom to study it. I’m still learning here. To be honest, I’m still not quite sure if it’s the Indium or something else that boost my last test result. I agree SAC305 is superior if we put thermal performance and tin whiskering aside. But for E21A, this is a nightmare. Almost all manufacturers prefer 63/37 than SAC305 for their E21A equipped products. My story with Indium started because of E21A. And never really cared for its superior thermal properties that much. I guess you also agree that thermal conductivity is not as important as thermal resistance. As long as we can make the solder joint very thin, the solder material used would not be too relevant. Will get back to this after finishing my other tests. - Clemence

Since lead solder is banned in EU and most other countries, it’s strange that manufacturers are allowed to use it in their E21A products.

These kind of measurements definitely should not be done with LEDs as heat sources, thermal resistance, Vf, efficiency from LED to LED can vary –5% for same bin, all this can make dissipated heat different enough to make such tests questionable. This problem could be eliminated only by testing larger number of LEDs, but even 3 LEDs from same batch for each solder type measurement could give us a more valid clue.

Other solution would be to use small size power resistor in package similar to lfpak33 or something like that, in that case you exactly know how much power is dissipated (U*I), by measuring resistor top side temperature you can compare and see which solder or soldering technique performs better, and by how much. Also you eliminate light measurements which are one of the most inaccurate measurements in technology, temperature measurement is very simple and accurate (PT100 sensor).

Thanks for your input L4P

- Clemence

clemence · February 18, 2019, 5:24pm

Currently, I don’t have all needed setup to make a valid experiments. And after some thoughts, it’s better if someone else do the test. People would think I’m biased to something that I sell. I’ll gladly provide some test specimens and materials to those who wants. Djozz, Koef3, Maukka perhaps?

In the mean time please hold all conclusions until a more valid test is done.

- Clemence

Texas_Ace · March 3, 2019, 2:58pm

I know I am late to the party, This thread was just pointed out to me. I was not aware that a 219D was out.

How is the tint on it? Do we finally get rosy 219B tints with 219C output?

I have not been able to find a high CRI LED I like from any manufacture since the 219B 9080. They are all green!

ggf31416 · March 3, 2019, 4:18pm

219D is old news, CRI 70 and only a minor improvement in output and throw. There were reports of the 219D LED turning blue on turbo mode in the Folomov 18650S flashlight.

TL;DR it s*cks.

Texas_Ace · March 3, 2019, 4:43pm

Ah, thanks for the info, I assumed it would have 90cri like the rest of the 219 series.