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Messages - mrehmus

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1
Inspiration / Re: free book on laser cutting/engraving
« on: January 14, 2018, 12:43:23 PM »
That is why you use a temporary e-mail address or mark their incoming as spam. Not a problem if you know what to do.

2
Inspiration / free book on laser cutting/engraving
« on: January 13, 2018, 06:33:56 PM »
http://laser101.fslaser.com/ebooks?submissionGuid=77046aff-72c0-4915-95d3-9bcc6d3a3419

They want your name and e-mail address but the book looks useful.

4
Inspiration / Another source
« on: January 05, 2018, 09:58:14 AM »

6
Cutting / Re: 2500mW laser beam issues
« on: December 23, 2017, 09:04:37 AM »
That is what my beam looks like. I have a new lens that I hope will do a better job of focusing. But I thought I understood that the diode lasers do not emit a circular beam.

7
General Discussion / Take a look at this cheap and easy cable chain.
« on: December 22, 2017, 01:46:22 PM »
https://hackaday.com/2017/12/17/diy-cable-chain-looks-great-stays-cheap/

You can get a cheap tape measure at Harbor Freight. Sometimes they are even free with another purchase.

8
FAQs For New Users / Re: If you could do it over, what would you buy?
« on: December 13, 2017, 05:33:33 PM »
My experience with a blue 2.5 watt diode laser on an EleksLaser A3 Pro says it's great for engraving but inconvenient for cutting. Therefore, I also have a K40 CO2 laser that has an output power of 37 W and yet too small to cut an 4 mm birch plywood at once.

Regards Leif.

Would you elaborate on your experience with the 40- (32) watt unit? I am contemplating whether the 50- or 60-watt versions would be better. I am interested in cutting 1/4 inch (6.35mm) plexiglass and plywood. In the section on the 40-watt units if you would.

9
FAQs For New Users / Re: If you could do it over, what would you buy?
« on: December 13, 2017, 04:33:26 PM »
I'd buy a 40-watt CO2 unit or maybe 50 or 60 Watts. But now that I've had the 2.5-watt unit, I know that I need much more power to cut plastic at 1/4" thickness. The 2.5-watt unit works fine but it won't handle the thick stuff or difficult stuff like gasket material that has rubber in it.

10
Engraving / Re: How long do you run your laser for?
« on: December 12, 2017, 04:15:26 PM »
I think you both are saying the same thing. Stonemull is using 30 min vs 2 hours as an example. I have no problem with the numbers. It could be 2 minutes or 5 hours, the point is you must dissipate the heat or the device will self-destruct.

No, we are not saying the same thing. He is saying that time and temperature don't matter, that only the temperature matters. Devices have a curve of temperature vs time to destruction. What applies to ICs also applies to any semiconductor.

Here is what Micron Technology states: The time frame and random field failures in the useful life of the IC can be predicted using statistics based on lab data from a sample of parts and will vary greatly depending on the operating temperature of the IC. This process is explained in detail in the following pages. 
If you want to read the entire paper, use this URL: https://www.micron.com/~/media/documents/products/technical-note/dram/tn0018.pdf

11
Engraving / Re: How long do you run your laser for?
« on: December 12, 2017, 09:44:32 AM »
It is only the maximum temperature that matters, not the length of time.This applys to the power supply as well as the laser, I cannot see any way 2 hours could ever be meaningful, it will be as hot as it will ever get after 30 minutes or so, after that it does not care if an hour more or a thousand hours.

Not correct. Time and temperature have an effect on semiconductors. The longer they are too hot, the quicker they will fail, statistically.

That said, I run mine for five or six hours but I have an airconditioned shop so it stays at around 70 F max.

12
General Discussion / Re: Compressor for direct air
« on: December 08, 2017, 07:37:05 PM »
Harbor Freight has a sale on a 1\3 hp 100psi pancake compressor for $35.  Will this work for cutting and engraving? What else will I need in the way of tubing and the end piece for blowing?

Yes, it will but it is very noisy and it runs out of air quickly.

13
General Discussion / Re: howto fix laser diode
« on: November 28, 2017, 09:05:57 PM »
Heat conducting epoxy has metal in it.

14
General Discussion / Re: howto fix laser diode
« on: November 28, 2017, 03:39:49 PM »
You can also use heat conducting epoxy. Something like Delta Bond which I've used to fasten semiconductors to heat sinks.

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