Lasever 200mW 532nm

[sbk]

Just got a Lasever LSR532ML 200mW module direct from David.
Was sent on saturday, and was on my home tuesday morning! Incredibly fast shipping

The laser is working very well : I measured a peak over 300mW on warm-up but the average power is between 250 and 280mW, so a lot over the specs!
Beam is TEM00, and has a great divergeance.
Like the other small Lasever modules, you have to insulate both head and driver as they are getting warm

[buffo]

Like the other small Lasever modules, you have to insulate both head and driver as they are getting warm

Um... don't you mean "heat sink the head and driver"? Insulating them would make them get even hotter because the heat couldn't get out.

Adam

[dave]

Hehe,

we just received a couple of cni 200mw's, and the powers were 325mw and 365mw after warmup

[dave]

Um... don't you mean "heat sink the head and driver"? Insulating them would make them get even hotter because the heat couldn't get out.

Adam

not if you use silicon impregnated heatsink insulation. I think farnell sells it in sheet form...

[buffo]

Good to know that Chinese lasers are getting serious about their specs. It's a hell of a lot better to be over-spec than under, at least when it comes to power output.

Maybe they're doing better quality control and pre-shipment testing these days? If so, that's a good thing.

Adam

[buffo]

not if you use silicon impregnated heatsink insulation. I think farnell sells it in sheet form...

I've never even heard of this stuff... Is it electrically conductive? (My guess would be no, since it's sillicon impregnated.) How good is it at conducting heat then? Do you use it on your lasers Dave? (Between the head and the baseplate maybe?)

I've heard of people using arctic silver thermal compound inbetween the head and the baseplate of the optical table to increase the rate of heat transfer, and I've also heard of people adding heat sinks to the head (and the driver) to help keep everything cool. But this is the first time I've ever heard of heatsink "insulation"...

Details, please!

Adam

Edit: I looked around on the Farnell site, but under thermal management products a search for insulation only turned up insulating pipe (which was no longer stocked). A quick google search suggested that heatsink insulation is normally made of mica and doesn't conduct heat very well at all. It's used to electrically isolate a metal can power transformer from a common-rail mount, but several websites point out that it often causes overheating problems. Why would you want to use this on a laser that already runs hot to begin with?

[steve-o]

I work in electronics, and heatsink compound or thermal heat conducting pads are used (usually) under the components to fill in any gaps that may exist in the irregularities of the metal to metal contact to improve the efficiency of heat transfer. Silicone based compounds (such as dow-corning 340- what we use here at work) are not electrically conductive but should not be used as an insulator or electrical isolator due to metal-to-metal contact in some areas of the mounted device.
If you insulate an electronic power device (transistor, laser module, etc. it would cause more harm than good because some of the heat is dissapated through the top of some devices (see Marconi's design with the heat-sink fins on top), but the main heat transfer point is still on the flat bottom (more area=more transfer). I hope this clear-as-mud explanation clarifies the issue, although I'm not sure about the application referred to. Possibly the terms insulation and isolation are being transposed or being incorrectly interpretated.
Cheers,
Steve

<edit> mica is used for electrical isolation and does conduct heat but must be used in conjunction with heat sink compound for heat transfer. I don't know if "artic silver" is h.s. compound (have not heard of it) but I assume it is similar if used for the same purpose.

[buffo]

Thanks for the input Steve-o. You and I are on the same page then.

BTW, actic silver compound is a brand name for a popular thermal paste (also known as thermal grease) that is often used for CPU heatsinks. Basically it's similar to the heatsink compound you were referring to, except that it's marginally better than the stock thermal grease that comes with a CPU kit. (And quite a bit better than the head-conducting pads that come on the really cheap CPU heatsinks, though that's primarily due to the thickness of those pads vs the much thiner layer of paste that is normally applied.)

But getting back to the laser application - yeah, I don't see how any form of heat sink insulation (whether mica or silicone based) is going to improve the heat transfer from the head to the baseplate. (Quite the opposite, actually.) I'm still curious as to what Dave was referring to though.

Adam

[steve-o]

Yeah me too.
The stuff we put the grease under are 200-300 amp IGBTs and other similar power devices (industrial motion control.) Must be different than CPU stuff, I dont know that much about motherboards and computer stuff
(except how to crash them sometimes )

[marconi]

I think he was refering to its use for uneven metal to metal contact.
And without the mess.
Its the same stuff I use.