6215H Heatsinks for xy block

[kecked]

WHAT KIND OF HEATSINKS ARE PEOPLE USING FOR THE 6215h SCANNERS?

I calculated 0.15 C/W is needed with a max Junction of 50C. So starting at 32C that only gives you 18C rise. Since they do max worst case 120W thats 18C/120W=0.15C/W. The Junction Case C/W is 1C/W. So adding it up, you get a neagtive C/W meaning you need active cooling. This is obviously not what is being done so I'd like to know what you are doing. Also anyone know the ratings and max junction temp for the big boy scanner amps? Guess I can look up the driver trans and get the curves. I used 32C as a worst case, that is only 90F so on a warm day that might not even be worst case inside the projector.

Thanks,

[mixedgas]

Copy LFI and put a mini fan on the bottom of the heat sink. After you extend the standard heat sink a bit to provide a larger thermal mass to cool. You need a certain minimum mass for uniformity.

Steve

[dsli_jon]

hey Sir P -

Copy LFI and put a mini fan on the bottom of the heat sink.

yeah, ∆ what he said... ie:



...'conveniently' for sale at a rock-bottom 'BFF' price, and yes, I have the sleeve 'adaptors' for the 6215 > 6800 hole.. free! (with purchase...) ..but If you want it just for 'testing' / R&D, I'd be happy to loan it to ya, tho, free! (w/O the strings...

Though, I gotta-say - I've put CTs thru quite some ringers / gauntlets, as I know many-others have, and I gotta say - I can't ever think of one time when they 'thermed-out'.. shut-down for overscan-angle / overspeed, yes, but iirc, nary a 'thermal-trip'... What are ya scanning, rasters on the moon?

Lemme know, I'm actually passin-thru / nearish SB tomorrow nite...
ciao
j

[Jem]

Hmmm...

Just seen this thread. Mine are mounted directly on to the baseplate, is that wrong?

Jem

[kecked]

Thanks for the offer. Jem, do your 6215H scanners ever even get warm attached to the baseplate? I have a 0.1c/w 5x5x1.5" heatsink coming with 4 fans mounted on the back. However, if I can get away with just the baseplate thate would be great. Do you have the drivers bolted to the plate as well? How big is the plate?

I just got my scan block and it is already 2" tall so if I add that fan on the bottom it it won't fit in my case. Nice job though and thanks for the offer.

I'm hoping to build this thread with peoples experience so everyone in the future knows the reality of the required heatsinking. Right now I've heard no heatsink bolt it to the plate all the way to massive tec cooling.

I'm drilling a 1/16" hole in my block so I can add a thermocouple. I'll post my results on a baseplate and with the fan cooling. If that fails I'll move to tec cooling.

BTW I have the onestoplasershop 2" tall block and it is massive. It sucks the heat right out of your hand and makes yor hsand feel cold.

[Jem]

Hi

Yes, I had a problem where the baseplate got so hot it was painful to touch it . The problem was caused by a 'custom' 445/473 TEC cooled combination laser. I actually thought I had damaged my scanners as they had become extremely hot and the test pattern looked awful. They were removed from the laser projector and sent to Bill at Pangolin for tests. Bill contacted me to say there was nothing at all wrong with them and they were still perfectly in tune, it must just have been a glitch due to them being hot at the time I projected the test pattern. He returned them to me and they were refitted into the projector. Since then I have removed the 445/473 combuination and use a single 445 diode with no TEC cooling. The baseplate now doesn't get so warm. If the projector is doing some heavy abstract scanning the scan block does get quite warm although nowhere near as hot as it did before, and now i'm aware of the extremes of temperature these scanners can be pushed to i'm much more relaxed about the whole heat issue.

In my humble opinion the CT6215H scanners are absolutely amazing . The size of my baseplate from memory is approx 8" x 18" x ½". I have approx 400mW of 660nm, 350mW of 642, 500mW of 532 and ~750mW of 445. So, in all ~2 watts at full power

In an ideal world i'd use a bigger case as it's *very* tight in there (ask Rob - Stanwax ). The biggest problem was the size of power supplies needed to feed the scanners

Hope this helps, but if you need anymore technical information i'd contact rob (Stanwax) as he rebuilt my projector for me.

Cheers

Jem

[kecked]

That's a keeper of a reply. So it sounds to me like the 5x5x1.5" heatsink 0.1c/w with fans is the best approach. The use of TEC in such a cramped space (mine is 12x18) is not going to work. I'll let you know how it goes. I think I will chance dumping the drivers into the plate though. You have the optical power setup I have. I do not want anything brighter. This is near the limit of my tolerance for pain! Will report in a month or so when the scanners come and Ican post some actual measurements of the scanner case temp verses the heatsink. I will also do a direct bolt to the plate and measure just fo the data point. I'll let it run until it stabalizes in temp or exceeds a scanner case temp of 40C with a full on grid pattern running at 60k and 2,5,10,15 degrees of scan angle. Heck I'll even try doing current curves as well. Maybe it will be possible to limit temp by watching the rms of the signal. Might be able to use a peak detector to warn the user if they are getting near the limit.

Last, no matter what I'm adding a thermocouple in the block touching the scanner case with an led that will tell the temp in a bar graph along the side of the projector. simple cheap and direct.

Here is my favorite heatsink supplier. www.coolinnovations.com

[Jem]

You pretty much lost me after the first sentence ... Just kidding, but I have to say my electronics skills are limited. Basically I just wanted to get them fitted and working and gave little thought to the heat issues. To be honest I don't think i'd have had a problem had it not been for the overheating blue laser module. Interestingly it was initially thought that these C*sio blues would need TEC cooling and that's the avenue we went down. However, it seems it's since been proven that you can abuse them quite badly before they finally submit. Therefore it appears that it's better from a temparature control point of view to avoid a TEC on a single diode unless you can easily get the heat caused by the TEC away efficiently.

I also have a thermocouple sat on my bench along with a nice little digital display. I just need to get it fitted into my projector , that's yet another job on the 'to do' list

I'll be interested to see your results though.

Take care

Jem

[kecked]

I just thought of a second approach which I think is the one I will try. Instead of using a giant heatsink I'm going to get 2 2"sqx1.5" high heatsinks and mount them to two sides of my scanner block and also bolt it to the baseplate. That increases the contact area from 4"sq to 12inch" sq. so more surface area gets the heat away faster and I also get a smaller footprint in the case. I'll let you know how it goes.

[Jem]

Ahh.... That sounds like a plan