comparisson of temperature change to loss of power

[waltfl]

hi
just a note at the side especially for florida I am in south west florida and I can tell to run a laser in a un air-conditioned space the cooling water temperature goes pretty fast in the range where the tube gets destroyed above 15degree Celsius (78F) there the tube starts loosing integrity and then the front lens cooling chamber comes off and that's it.
if the temperature goes below 60F the cutting power does not go down it stays .
I have a window A/C running which also is used as cooling for the water with a 120mm register ( see picture) and I have on very hot days ( above 95F) a hard time to get the temperature below 24C .
this small fridge will probably not do for heavy cutting.
just some notes
greetings
waltfl

Wow, I would have never guessed that temperature changes in that range would make a noticeable difference in cutting power at all. I figured that it would affect the tube life, but not cutting power. Many thanks for the good information. So what happens if the temperature gets below your ideal temp? Does the cut power go down?

I had been playing around with different speeds and power and writing down what works best. Now that I know it is so affected by temperature (and since I have my machine in an un-air conditioned space in Florida, my database I have been building up does not mean much. Looks like I need to get my temperature controlled at a steady state just so that my preset speeds and powers work all the time and I don't need to make adjustments all the time.

I am thinking that modifying a small fridge would work OK. I have seen some small ones that are made to cool just a six pack for pretty cheap. just put a quickie temp sensor and controller on it and should be quick and cheap.

[NickWL]

I tried a 120mm radiator with a mains-powered fan: useless.

Then I tried a six-pack/camping fridge (240vAC and 12vDC - it was cooled by a Peltier-effect cell), took the door off, lay it on its back, sealed the gaps and used it as a reservoir: hopeless.

What I ended up buying on eBay was one of these: Arcadia Aquarium Chiller 500ltr 250w AT250 Summer Fish Tank Water Chiller; I've never looked back. I always run the chiller and circulating pumps for a while before firing up, so as to avoid thermal shock.

Here's a picture of the setup - I've omitted the pumps because a) the picture is cluttered enough already and b) if you can't work them out for yourself your mummy shouldn't have let you play with lasers in the first place!

FullSizeRender.jpg (79.93 KiB) Viewed 4045 times

[waltfl]

hi nick
they are way to expensive for a water chiller, the system I use is a 20.000 BTU window AC with the radiator and it holds the room temperature at a normal ;level and the same time it cools the laser water.
the window AC and the radiator cost about the same as the aquarium chiller .
greetings
waltfl

I tried a 120mm radiator with a mains-powered fan: useless.

Then I tried a six-pack/camping fridge (240vAC and 12vDC - it was cooled by a Peltier-effect cell), took the door off, lay it on its back, sealed the gaps and used it as a reservoir: hopeless.

What I ended up buying on eBay was one of these: Arcadia Aquarium Chiller 500ltr 250w AT250 Summer Fish Tank Water Chiller; I've never looked back. I always run the chiller and circulating pumps for a while before firing up, so as to avoid thermal shock.

Here's a picture of the setup - I've omitted the pumps because a) the picture is cluttered enough already and b) if you can't work them out for yourself your mummy shouldn't have let you play with lasers in the first place!

FullSizeRender.jpg

[NickWL]

Not here in the UK they don't Walt!
Our climate makes domestic AC units virtually unheard of and most of our homes and work environments sit at 18-20 degrees without much help for most of the year.
Besides, I didn't think £100 ($160) was too bad a price to optimise tube performance AND lifetime!
Nick

[WarpedMindGames]

I wish I would have found this post a couple months ago.

I have had a K40 laser now since June, and I must say that the documentation and software (LaserDRW 2.013) has MUCH to be desired. The "manual" for the K40 states the water temperature should be around 39 degrees. There was no C of F afterwards so originally I was thinking the water temp should not get above 102 F because the laser is from China and they probably use C. (quick math conversion of 39C comes to 102.2F). I happily ran my laser for about 3 weeks and never let the cooling temp of the water in the bucket get above 80 F and had some great results (and great acrylic fume highs because I didn't put the exhaust in right). I did some research online, again before finding this site, and found out, on several sites, that the cooling water should be 39F. I have since been spending about $100/month USD on ice to keep the laser "cool". Thankfully I don't think I've trashed the tube because I would get the water temp to about 34/35F and let the water circulate through the tube for 30-45minutes hour before doing work.

NOW I understand why the engrave is fantastic but it takes 5-6 passes at some unknown (the software claims 75%) to cut 1/4" Acrylic @ 20mm/s. This of course wrecks the material I am working on (melting and becoming distorted and brittle).

I live in Ohio and I have the laser in an unheated garage, this time of year the garage temp is around 55-60F. My cooling tank is a 25 Gallon Sterilite/tupperware storage container with lid that is filled with 3 gallons of distilled water and I only use ice from a local company that actually makes the cubes from distilled water. I have 4 small holes in the lid of the tank that run the water in/out and power for my pump. I built a "splash tray" to the underside of the lid so that the return water splashes on this tray which makes noise and allows me to see the water droplets easily (to make sure the pump continuously runs). I also have a small, Made in China, water temperature gauge with submersible probe. I taped the gauge north of the laser control panel and ran the lead over the back of the laser and down into the bottom of the cooling tank. The gauge also measures ambient temperature outside and I can set alarms for high/low.

What my process previously has been is to fill the tank with ice, cover it, run the laser until the water temp alarm goes off because it reached 50F (arbitrary number i picked) then stop and drain off water/add ice as needed and rinse/repeat the process of letting the water get down to 34/35F etc etc. During the summer time 100 lbs of distilled ice cubes lasted about 4 hours, with the seasons changing I expect by middle winter I will use ice rarely/if at all.)

I think what I need is a good/inexpensive setup. I see water chillers ranging from $300-$1000 that are sealed systems (yes, i know every time i crack the lid on my tank I contaminate the supply) and I am running on a very low-budget start up company right now. Any suggestions on simple changes to what I am already doing, what I am doing drastically wrong, and/or what I am doing right?

So far I've had no electronics related heat issues.

I have 0 previous experience running any sort of laser and have hit just about every landmine I think is possible at this point. And I have found that a lot of the information, if you can find it, on the internet is terrible at best. THANK GOD FOR THIS SITE.

At some point I will have to get pictures together and show everyone what I blindly have done without want or warrant to this laser in order to "improve" it. You guys may find it interesting.

[WarpedMindGames]

I just looked up the said aquarium pump you recommended and it is £389.97 on eBay UK...sounds like you got a steal!

[NickWL]

I did!
But I waited about 6-8 weeks just watching aquarium chillers on eBay and pounced when all the stars were correctly aligned!
£100 plus an hour's drive to Bristol (carriage would have been a stinker) and same back.
Nick

[Tech_Marco]

Too bad I don't have time. Otherwise, I can show you guys the DIY water cooled cooler
Just don't have time to finish my project. It should be good enough to be used to cool off a 60W through evaporation.
It won't cost over $100 (my estimate)


Marco

[greg_gran]

My first post here, but I've got some experience with other equipment watercooling and couldn't resist chiming in
I just snagged a K40 with all the LightObject upgrades, and I too am wondering about optimum cooling temps for a 40 watt laser tube.

I don't doubt that cooler is better, but it seems like temps in the mid 30F to low 40F range are impractical for most people because of dewpoint issues. Maybe you could get away with those temps in the dead of winter when dewpoints are below freezing. 15 kilovolts and a sweating laser tube doesn't sound like a good idea to me

I am curious to know if coolant temps that low really do enhance the laser output power.

As far as coolant goes, I plan to use distilled water with 5% Isopropynol added in a closed system (ThermoTek Chiller). The objective of the alcohol is to prevent biological growth, which I'm sure will happen sooner or later without a biocide of some kind. I don't think alcohol will do much in an open system because it will evaporate out quickly.
Perhaps a few drops of bleach once a week would work...

I wish I would have found this post a couple months ago.

I have had a K40 laser now since June, and I must say that the documentation and software (LaserDRW 2.013) has MUCH to be desired. The "manual" for the K40 states the water temperature should be around 39 degrees. There was no C of F afterwards so originally I was thinking the water temp should not get above 102 F because the laser is from China and they probably use C. (quick math conversion of 39C comes to 102.2F). I happily ran my laser for about 3 weeks and never let the cooling temp of the water in the bucket get above 80 F and had some great results (and great acrylic fume highs because I didn't put the exhaust in right). I did some research online, again before finding this site, and found out, on several sites, that the cooling water should be 39F. I have since been spending about $100/month USD on ice to keep the laser "cool". Thankfully I don't think I've trashed the tube because I would get the water temp to about 34/35F and let the water circulate through the tube for 30-45minutes hour before doing work.

NOW I understand why the engrave is fantastic but it takes 5-6 passes at some unknown (the software claims 75%) to cut 1/4" Acrylic @ 20mm/s. This of course wrecks the material I am working on (melting and becoming distorted and brittle).

I live in Ohio and I have the laser in an unheated garage, this time of year the garage temp is around 55-60F. My cooling tank is a 25 Gallon Sterilite/tupperware storage container with lid that is filled with 3 gallons of distilled water and I only use ice from a local company that actually makes the cubes from distilled water. I have 4 small holes in the lid of the tank that run the water in/out and power for my pump. I built a "splash tray" to the underside of the lid so that the return water splashes on this tray which makes noise and allows me to see the water droplets easily (to make sure the pump continuously runs). I also have a small, Made in China, water temperature gauge with submersible probe. I taped the gauge north of the laser control panel and ran the lead over the back of the laser and down into the bottom of the cooling tank. The gauge also measures ambient temperature outside and I can set alarms for high/low.

What my process previously has been is to fill the tank with ice, cover it, run the laser until the water temp alarm goes off because it reached 50F (arbitrary number i picked) then stop and drain off water/add ice as needed and rinse/repeat the process of letting the water get down to 34/35F etc etc. During the summer time 100 lbs of distilled ice cubes lasted about 4 hours, with the seasons changing I expect by middle winter I will use ice rarely/if at all.)

I think what I need is a good/inexpensive setup. I see water chillers ranging from $300-$1000 that are sealed systems (yes, i know every time i crack the lid on my tank I contaminate the supply) and I am running on a very low-budget start up company right now. Any suggestions on simple changes to what I am already doing, what I am doing drastically wrong, and/or what I am doing right?

So far I've had no electronics related heat issues.

I have 0 previous experience running any sort of laser and have hit just about every landmine I think is possible at this point. And I have found that a lot of the information, if you can find it, on the internet is terrible at best. THANK GOD FOR THIS SITE.

At some point I will have to get pictures together and show everyone what I blindly have done without want or warrant to this laser in order to "improve" it. You guys may find it interesting.