DTR 20mm Module Heatsinking Capability

[_xXx_MLG_PiNgU_69420_xXx_]

Hello,
I am planning to do a C6 PLTB450B @1.8A build. I am curious about the heatsinking capability of DTR's 20mm modules (the ones with an aluminum back half). Do they provide a better duty cycle than Survival Laser's extended and tapered copper heatsinks?
This will be my first build, and I will probably do it in a month or so.

 

[paul1598419]

It sounds like you plan to use the 20 mm module as a heat sink. It might be enough copper to give you a reasonable run time, but I like to use more heat sinking for the 1.8 amp driven blues. But, that's just me. I have these kinds of diodes in MS Envy and MS-SSW-II hosts with larger aluminum heat sinks. Both give close to an unlimited run time. I do like copper better for heat sinking as it has ~1.6 as much thermal conductivity as aluminum.

 

[_xXx_MLG_PiNgU_69420_xXx_]

Yes, I am planning to use the 20mm module as a heatsink.
But is it a better heatsink than the SL extended and tapered copper heatsink, assuming everything else remains unchanged? I don't know it's weight, but it appears to be just as long.

 

[paul1598419]

You would have to ask SL what the mass is of their copper heat sink and compare it to the mass of DTR's copper 20 mm module. I doubt anyone has used both in a comparison to give you the information you are looking for.

 

[_xXx_MLG_PiNgU_69420_xXx_]

It says on SL's product page that it weighs 58g, if I remember correctly. I don't know about the mass of the 20mm module.
EDIT: Nevermind, I tried to check the total price with SL's Bargain No Diode Host Bundle instead, and turns out it's actually about 10-15€ cheaper, because of the extra price of the bigger module and the adapter for it, as well as because I'm not using neither a G2 or a 3E lens from the 20mm adapter bundle. I'll just go with the extended and tapered copper sink instead.

 

[_xXx_MLG_PiNgU_69420_xXx_]

On second thought, as this will be my first Class 4 laser, I'll use a 1.25A driver and a 3E lens (should be about 1.1W instead of 1.9W), so that I don't accidentally burn my house down or something. That way, it costs pretty much the same for both the 20mm module and the extended and tapered copper heatsink, so I'll just use the 20mm module, as I really don't like how th extended and tapered copper heatsink protrudes out forward, and I also like the look of the 20mm adapter. Also, I figured out the weight of the 20mm module on DTR's website (2.3oz = 65.2g for the full copper ones) which is more than the extended and tapered copper heatsink's 58g.

 

[paul1598419]

That is certainly a plan. Most drive these at 1.8 amps with a short focal length aspheric lens. The divergence on these isn't too bad, so you don't have to use a three element lens if you don't want to.

 

[_xXx_MLG_PiNgU_69420_xXx_]

I know, but I really want to make the most of the diode's low divergence, and also to reduce the power so I don't burn down my house by accident.

 

[paul1598419]

Meh, if you are careful what you point it at, you needn't worry. Some have claimed that they have scorched the white paint on their walls with 2 watt lasers, but I have never been able to make any marks on my walls with a three watt laser. They will burn ordinary plywood if focused on it. That is pretty much what I use to see if my lasers will still burn.

 

[_xXx_MLG_PiNgU_69420_xXx_]

Then G2 it is. How much divergence should I get with a G2? Also, is SL's G2 any worse than DTR's? Because it is cheaper if I get it with SL's DTR 20mm module bundle. And I only now thought of it, but is the aluminum back half good enough? Because I can only get the aluminum back half module separately for this 5.6mm diode, which is cheaper than buying the already pressed one with lead wires, which do heve a copper back half option, but increasing the total cost by ~10€.

 

[paul1598419]

RedCowboy has noticed the SL G2s are not centered properly in the lens housings lately. It is a major problem if you need to align your laser. The G2 from DTR has always been a more expensive short focal length aspheric lens than any of the Chinese versions of them. There are even cheaper versions on eBay than the SL one. You should expect to get up to 25% more power with a G2 over the 3 element lens. Also check that the AR coating matches the wavelength of the laser you want to use it on.

The aluminum back half won't add to the thermal conductivity of your module. So, if you don't need it, don't get it.

 

[Benm]

How is this module a heatsink though?

I'ts a module that connects a laser diode TO a heatsink like a flashlight host, but it only transfers heats, it's not intended to get rid of this heat into the environment by convection or radiation. After it heats up it's just a fairly short piece of 20 mm diameter metal.

You may use it's thermal capacity to create lasers with high power but very short duty cycles, but if you want something with power that can run permanently you do need proper heatsinking.

 

[paul1598419]

How is this module a heatsink though?

I'ts a module that connects a laser diode TO a heatsink like a flashlight host, but it only transfers heats, it's not intended to get rid of this heat into the environment by convection or radiation. After it heats up it's just a fairly short piece of 20 mm diameter metal.

You may use it's thermal capacity to create lasers with high power but very short duty cycles, but if you want something with power that can run permanently you do need proper heatsinking.

I couldn't agree more, but he is using a SL host that has a 20 mm copper module/heat sink. He is limiting the current to 1.2 amps, which is still a lot, but not as much as most drive this diode at. It will still have a limited run time. I believe his considerations are expenses over best practices.

 

[Bacon]

If it helps; here is my 20mm DTR next to a SL tappered copper heatsink.
I would say the SL has just a little bit more chunk to it; especially with a full copper 12mm module installed.
(I got the 20mm wired w/ driver at the time because I was being lazy)

 

[_xXx_MLG_PiNgU_69420_xXx_]

How is this module a heatsink though?

I'ts a module that connects a laser diode TO a heatsink like a flashlight host, but it only transfers heats, it's not intended to get rid of this heat into the environment by convection or radiation. After it heats up it's just a fairly short piece of 20 mm diameter metal.

You may use it's thermal capacity to create lasers with high power but very short duty cycles, but if you want something with power that can run permanently you do need proper heatsinking.

I know, but it's pretty close to te weight os SL's extended and tapered copper heatsink (their biggest one), and a C6 host is quite small, so it has limited potential for heatsinking. I am not very concerned about the duty cycle, as long as it can handle 30-40 seconds of on time. About SL's G2 lenses, I'm kind of on a budget, so I'll just get the 3E lens instead, and swap it out for a Sanwu G7 later.