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Author Topic: My first attempts at laser engraving.  (Read 91516 times)

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Offline Tweakie.CNC

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Re: My first attempts at laser engraving.
« Reply #90 on: June 27, 2009, 04:23:41 AM »
Hi Chris,

You really need to get goggles that have an optical density rated for the wavelength of the laser you are using. Welding goggles may protect your eyes but they are too dark to be of any real practical use.

Tweakie.
PEACE

Offline Chris.Botha

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Re: My first attempts at laser engraving.
« Reply #91 on: June 27, 2009, 05:25:07 PM »
« Last Edit: June 27, 2009, 05:29:20 PM by Chris.Botha »

Offline Tweakie.CNC

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Re: My first attempts at laser engraving.
« Reply #92 on: June 28, 2009, 05:01:54 AM »
Hi Chris,

If, like me, you need to wear spectacles for close up work then the goggle variety of protective eye ware are preferable as you can still wear your spectacles and wear the goggles at the same time.

Tweakie.
PEACE
Re: My first attempts at laser engraving.
« Reply #93 on: June 28, 2009, 05:02:56 AM »
Apropos of nothing, the latest price list landed in my inbox this am, Chinese stuff in US$...

25 watt CO2 laser tube $127 or 40W for $158
pukka DC PSU for above $172
ZnSe or GaAs lenses various lengths etc $30 to $45
Cu mirror $16 quartz / silicon / molybdenum too

So you're looking at 400 bucks for something that will actually cut and etch etc, vastly versatile with PWM or potentiometer control on the laser, and if you bolt it to the Z axis that takes care of movement too.

Now I'm going to ask you, how much are you spending on "experiments"?

I know I wasted 12 months and maybe 20% of the cost of my CNC conversion by being cautious instead of being bold, determining what was needed, and going out and doing it.

Offline Tweakie.CNC

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Re: My first attempts at laser engraving.
« Reply #94 on: June 28, 2009, 05:20:46 AM »
Looks good prices John - are you going to buy a kit of parts then ?.

For me, CNC stuff is not so much about 'spending money on experiments' it's all about acquiring practical knowledge and practical experience. The theory can easily be obtained for free.

Tweakie.
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Offline Tweakie.CNC

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Re: My first attempts at laser engraving.
« Reply #95 on: June 28, 2009, 07:06:59 AM »
Hi Chris,

The secondary cable on your laser controller board is for the TTL modulation input, if you choose to use it. The white wire is connected to ground and the blue wire is for the TTL signal (<0.5 Volt=closed and >2 Volt=open) this already incorporates a 'pull up' resistor so pulling the blue wire to ground turns the laser off and open circuit turns the laser on. The spec for the modulation input is TTL levels at a frequency no greater than 15 kHz.

Tweakie.
PEACE

Offline Chris.Botha

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Re: My first attempts at laser engraving.
« Reply #97 on: July 04, 2009, 06:50:43 PM »
Thanks for sharing all the information!
I’m ready to try this.
       My objectives:
1.   Add a bracket to my Romaxx CNC so that I could use either my Bosch Colt router or the laser without any change out using Mach3.
2.   Use the “Laser” to engrave wood only and if possible cut wood of a thickness of .0625 minimum and if possible up to .25.
3.   Always wear the proper type of “Laser” safety glasses.

Here is the unit I’m looking at: 
http://cgi.ebay.com/High-Power-Laser-Module-1000-mw-Cutting-Burning_W0QQitemZ180347420212QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item29fd8b3e34&_trksid=p4634.c0.m14.l1262&_trkparms=%7C293%3A1%7C294%3A30

A.   Will this meet my objective?
B.   I understand that I will need a power supply. Are there any other components that will be needed?
C.   Do you have other recommendations that you think would be better than this unit?
D.   Will this type of “Laser” have any issues with engraving on different types and colors of wood?
E.   If you cut wood, will you need to build or purchase a bed to lay the material on?

Thanks Again,
Bill
Re: My first attempts at laser engraving.
« Reply #98 on: July 05, 2009, 03:28:46 AM »

Here is the unit I’m looking at: 
http://cgi.ebay.com/High-Power-Laser-Module-1000-mw-Cutting-Burning_W0QQitemZ180347420212QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item29fd8b3e34&_trksid=p4634.c0.m14.l1262&_trkparms=%7C293%3A1%7C294%3A30



are you insane?
445 bucks for 1 watt and no PSU

you could just about put together a 25 watt co2 system for that money, and actually have full power control over the laser output via cnc / pwm

if you want to cut you need a lens / gas jet assembly, end of story, without it you're just melting your way through. and yes you need a cutting bed, always...

Offline Tweakie.CNC

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Re: My first attempts at laser engraving.
« Reply #99 on: July 05, 2009, 03:53:49 AM »
Hi Bill,

I will try to answer your questions as best I can. Please note that this is not definitive but just my opinions based on my experiences so far.

A. I have no working knowledge of these Turkish lasers as no one has yet reported back on their use. Provided the supplied lens will actually focus the beam to a spot the size of a pin point (within the available space on your machine) then the 1 Watt of laser power looks good.

B. Additionaly you will, I think, need to cool the diode casing with a larger heatsink and perhaps CPU type fan.

C. I have no recommendations.

D. Using a laser which is only 1/7 the power of this one - I have not had too much trouble with engraving different types of wood however the surface reflectivity of the wood is the controlling factor and a finely sanded surface seems to be better. Surface burn marks adjacent to the cuts are a problem to control however.

E. I suggest just laying the work onto a sacrificial board such as plywood would be OK.

Good luck with your project Bill - Please report back to the forum with your results.

Tweakie
PEACE