PDA

View Full Version : A question about operating conditions



David Somers
10-23-2013, 1:12 AM
So...another question.

I noticed that most laser engraver manuals say something like....Operating Temperature Range 0-45 degrees, humidity 0-95% non condensing.

Of course, I assume the temp range is celsius, though as a lover of cold air if it were fahrenheit I would be delighted!!!!

My question is....what is the reality here? I am not sure what I would have to do with my wife to allow an engraver in the house, so I assume it will be in the garage if I got one. I live in Seattle, WA on the US northern west coast, about 400 ft elevation. It is rare to hit freezing temps in the winter. Snows come only once or twice every few years. More typically winter days are 37 or so for the lows, and low 40's for the high. My garage, if no heater is running, will be 10 degrees fahrenheit above that.

Any thoughts or cautions about this environment? Oddly enough, rusting is not an issue around here. I used to have my shop a short distance from the water and never dealt with rusting. When I lived in Hawaii though, 30 miles from the ocean and 4,000 feet elevation things would rust as you derusted them. Yeeks!! Seattle is pretty benign in that regard.

Anyway...I am interested in what the reality is with these machines versus the operating ranges the manufacturers state?

Thanks everyone!

Dave

Rich Harman
10-23-2013, 1:48 AM
Nothing to worry about in this regard. As long as it doesn't freeze you will be fine.

Dan Hintz
10-23-2013, 6:33 AM
Lasers don't operate well at cold temperatures... it's difficult to pump the gas mixture well enough to get it to lase. If things are too hot, you're starting to stress the electronics (just like any computer). Humidity is pretty much irrelevant, except for the non-condensing part (you don't want liquid water anywhere near electronics for obvious reasons).

In short, you'll want some heat in the garage for those colder days, and you'll want to let the temp equalize for a couple of hours to avoid stressing the tube. I believe they've gotten better, but a number of the older Epilog tubes had issues with firing at the start of the day, particularly when it is a bit chilly... people typically ran them at full power for 5-10 seconds at the beginning of each work day before throwing in a real project.

Dave Sheldrake
10-23-2013, 7:10 AM
Stability is more the order of the day for lasers, if you run at 50F all day you will be fine, if you run at 34F all day you will be fine (DC Glass tubes) jumping between the two will affect beam quality and power delivery quite a bit.RF tubes as Dan said are a bit more picky, the living room would be a great place to have one (although divorce costs more than a laser) ;)

Good Chinese machines will stand an incredible amount of abuse (I'll PM you a review of one I beat to hell and it survived)

cheers

Dave

Mike Null
10-23-2013, 7:46 AM
I am one who believes a stable, clean environment is best. I have been engraving for more than 15 years with virtually trouble free results with both my former ULS and my current Trotec machines.

David Somers
10-23-2013, 12:13 PM
So...the message seems to be, keep it above freezing and try to keep big temp swings from occurring at startup.


In a conversation I had with Dave Sheldrake I mentioned the idea of putting one of the smallest golden rod heaters inside a laser printer when it was off and in a cool environment. Those are little rod shaped heaters that are only 35 watts or so. In something as small as even a big laser engraver it should be enough to keep the inside temp 10 degrees F above ambient, which would be more than enough to remove any concerns with condensation, and might reduce concerns about big temp changes produced by starting in a cold environment.


I am afraid I am one of those sick people who is overly warm all the time. When I worked at Crater Lake, 600 inches of snow each year, I would wear shorts on my off time year round and was perfectly comfortable. I am no longer quite that hardy (or perhaps fool hardy is a better term? <grin>) but I still think nothing of working on my lathe in the garage with the bay door up on a winter day in Seattle. Admittedly, that is only 45 on average, but still....


As I was writing this post it occurred to me that I have no idea what the power off or standby behavior is on these devices. The Chinese manuals I have gone through don't seem to talk about this.


So....I am curious. Do you folks physically power them down at night? Or do you leave them up all the time? If they are powered down are they still consuming electrons, and presumably generating some heat?


On a related note. I used to cover the Pacific Islands. One of my offices was right on the water, and had only solar power with battery storage. It was not air conditioned and so windows were always open. On my first visit there I installed some new computers, and a year later they all failed? Turned out they had rusted to bits in a year. Seems when they were turned off at night because they did not have enough power storage to leave them on, the cooling components would have salt air condense on them. When I opened them up after a year there was a rime of salt crystals on everything. Complete rust buckets. The solution was to bump up their solar capacity and storage and provide them with machines that could be hibernated at night so they still produced a bit of heat that prevented condensation. Interesting. Which is why I asked the question above.


Dave

Dan Hintz
10-23-2013, 12:31 PM
Ideally you'd keep the tube at a warm temp along with the main control boards... but a sleep mode wouldn't keep the tube warm as it's not running.

I would consider a couple of 25W incandescent bulbs in there, if you need a heater... you get the same benefit, but you also know when the "heating element" goes out.

Joe Hillmann
10-23-2013, 1:10 PM
Ideally you'd keep the tube at a warm temp along with the main control boards... but a sleep mode wouldn't keep the tube warm as it's not running.

I would consider a couple of 25W incandescent bulbs in there, if you need a heater... you get the same benefit, but you also know when the "heating element" goes out.


In a Chinese machine would a heater in the engraving area keep the electronics and tube warm? In my Universals the tube is in a separate compartment and some of the electronics are in yet another compartment. In both those compartments I don't think there would be enough room to put a light bulb.

Dan Hintz
10-23-2013, 1:39 PM
Joe,

One light bulb for the tube compartment, one for the main electronics compartment. Look for small 25Wers, like they use in microwaves (about the size of the old bulb-type Christmas lights).

I wouldn't call it an ideal situation by any means (I'd always prefer to have my machine in a controlled environment), but some don't have the luxury of conditioned workshops.

Dave Sheldrake
10-23-2013, 3:45 PM
Hi Dave,

The main supply to all my lasers is kept on 24/7 with the machines control powered up, the water circulation is also on 24/7 as cavitation / forgetting to turn it on on startup kills more tubes than pretty much any other reason (DC tubes).

Condensation / rust is a problem to avoid but most Chinese machines aren't too worried about a little rough treatment (as in the link I sent you ;))

cheers

Dave

Kev Williams
10-23-2013, 3:58 PM
I look at it this way-- Electronic equipment can withstand greater temp extremes than I can, so -- If I'm comfortable, my machines are comfortable! :)

FWIW my machines have always been in the basement of this house, and temps have likely never been below 58 or above 88. They just keep getting older and just keep on going. Maybe they like the temps down here?

Dave Sheldrake
10-23-2013, 4:19 PM
They just keep getting older and just keep on going.

I know that feeling Kev :) cept the getting going is my problem these days :)

cheers

Dave

Robert Silvers
10-23-2013, 5:53 PM
I installed a natural gas heater in my garage and put in insulated doors and leave it to never go below 50F.

David Linahan
11-01-2013, 6:43 PM
I have the opposite problem. My laser is in the back shed and cold isn't a problem at all...even in the winter. But, come the warmer weather and nearly every day is over 30C, which according to the book means its too hot to run the machine. I'm considering building a "laser room" inside the shed with an A/C to keep things cool. I'm not sure what problems the high ambient temperature causes...but it voids the warranty so I'm guessing it would be expensive.

Dave.

David Somers
11-01-2013, 7:02 PM
Dave,

86F? Ick. I am a confirmed heat wimp. My wife worked the last 2 years at Sequoia and Kings Canyon National Parks in the Sierra Mountains of California. Headquarters and the employee housing area was in the low lands which stayed around 107 for 6 months of the year. 95 to 100 in the evening! Downright chilly! The National Park Service used what we call swamp coolers to cool the structures. Basically evaporative coolers. They could knock 10 degrees off the ambient temp, but not much more than that, though they were far cheaper to run than an air conditioner. They don't perform well in humid climates though. I am not sure if Traralgon is humid or dry? A 10 degree drop might be OK from a high of 86F in order to get a working temp in your shop for you personally, provided you have a decent chiller for the engraver itself? I am guessing, but I would think you would want a real chiller as opposed to one that simply moves water from a bucket like the less expensive chillers do.

If you are in a humid environment at those temps I think your only solution is true Air Conditioning. One of the parks I covered in the Hawaiian Islands was quite warm. We used AC to keep our server racks cool. Fans didnt cut it, and a swamp cooler was a total waste of time in that humid, coastal environment. The amusing thing was the only room they had space available in for the server racks was the bathroom. So the ONLY room in the whole park that was air conditioned was the bathroom. If you were working on the hardware you had to keep vacating the room when someone needed to make use of it. Pretty amusing. I might note that bathroom breaks tended to run long at that office. <grin>

I am not yet a laser owner so take anything I say with a grain of salt by the way. I am just relating experiences with things in hot climates in general. The rest of the crew will chime in with real life experiences about high operating temps. Though the posts I have read suggest that high temps are tough on the life span of your tube, and may cause it to shut down while it is operating. High temps seem to be much more of a problem than lower temps.

Dave Sheldrake
11-01-2013, 7:43 PM
I'm not sure what problems the high ambient temperature causes

Short version,

You get thermal runaway of the gain medium (CO2 gas) leading to exponentially increasing saturation values. Basicly a dead tube pretty quickly. I can post up the exact details if anybody needs them but I just got home and it's 23.28 here and I've been out all day so sorry for the basic answer.

cheers

Dave