I was watching some high powered flashlight videos, the issue of heat and I wondered…
Is anyone making an attached but separated head. What I mean by that, the head is attached to the body by cooling ribs with an air gap between the head and the body. Even better yet, if they have done that, did they place a fan in between?
That would reduce the heat transfer to the hand grip and increase the underside cooling of the led.
If not, why not? It would make for a really cool and distinctive looking flashlight.
Interesting but no. I was thinking more of the ribs running parallel to the body.
It would be a bit of a pain to machine, but then, it would allow for a small fan that would be inherently protected,
inherently offer the best possible cooling and be cool like nothing else. The draw of a 1 inch fan couldn’t be anywhere near high enough to make a difference in a battery life.
Come to think about it, it could be a high power BLF design that would set the industry on it’s ear.
Having fins parallel to the body of the light does offer some advantages. You could have a fan blow down the length of the ribs for much superior cooling.
I’m not sure how you’d machine it though. I don’t think you could do it on a lathe. It might be really expensive to machine.
I thought about that and the only way is to machine it is to first lathe it and then vertically mill the fins. OR do the entire thing on a 5 axis CNC mill.
I open a thread to ask for some 3d rendering help.
Would be interesting to have vertical ribs going the entire length of the light. I think cooling would be quite good even with the fins not exposed except for an air intake at one end and exhaust ports at the other with a fan for air circulation.
I think I know what you are talking about. There would be just as good grip on it as checkering plus with far more surface area, better and faster cooling.
More heat is transfered from the lights body into your hand (liquid cooling) than from the lights body into air (air cooling).
Flashlights arnt a new thing, if vertical ribs worked better they would have been implemented by now. Seems to me like all vertical ribs would do is decrease the contact area between hand and light body decreasing the cooling ability of the light…
Not saying it won’t look BA, but it won’t work any better.
Also since you’ve brought up fans what’s your plan for water resistance? Fans, especially tiny ones die when submerged cause the force needed to move liquid is so much higher than air their little motors just instantly die regardless whether they’re IPX sealed or not. On the few forced air cooled lights now I believe the fans are usually designed to sense water egress and shut down immediately to prevent burning up the tiny little motors.
It’s dead easy to make horizontal fins on a lathe. Easy = cheap so not surprising they appear on many lights.
Also, I think the main advantage of horizontal fins is that a fan could blow along each fin providing much superior convection. A fan on horizontal fins isn’t as good since the fan’s blast would be deflected away from the light as soon as it hits the first fin. This is why most PC heatsinks use a series of radial fins with the fan blowing air down the length of each fin.
In a flashlight, I don’t think vertical fins offer any real advantage unless the light also uses a fan. And right now fans are specialty items found in very few flashlights.
There would be less heat transferred if the connection was ribs. There is less mass conducting the heat and that finned mass is now subject to faster cooling.
More expensive to make. It would require one more machining step. On the other hand, machining is relativly dirt cheap these days.
That’s why I started the thread.
I spent an hour on Google trying to find something that looked like what I was thinking and nothing. So chances are nobody has made one.
You asked and answered the question.
The separate head can be machined with much more surface area for passive cooling. Cooling ribs not only on the sides but also underneath the head. The fan, if there is a fan, would add yet another level of better cooling.
The ribs running parallel, connecting to the body would decrease the amount of heat transfer. I don’t know what is the working temperature of leds and their boards, but I assume it’s far higher then what we can withstand.
Then there is also the benefit of not transferring heat to the batteries.
A smaller shop would not want to invest in a 5 axis mill. So the way to do it is to machine a solid block on a CNC lathe then finish it on a CNC mill. The CNC mill can do the fin design and put the ribs/fins on the back of the body.
If the flashlight company is doing their own machining, they probably have a CNC mill to do the end caps. That can also do the fin machining.
Zn can be cast, and it’s lightweight. We had a local mfr who’d do cast-Zn molds for production parts (everything from gears to whole cases), and once the mold’s done, you can get (amortise) a pretty low cost per part.
No idea what kind of volumes They™ do for flashlights, whether 1,000s or 100,000s, so can’t say anything about the economy of making cast-Zn parts. Think Mg was supplanted by Al for most things except hard-drive parts where you don’t care about cost as long as it’s light.
