engraving timing and power settings?

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engraving timing and power settings?

Postby educa » Sun Feb 12, 2012 10:33 am

Hi,

Since I will try to create all needed electronics myself (using microcontollers (multiple ones) ) I am preparing for what I will need.

The part to control steppers and even the part to control the laser on/off including PPI pulsing is not a problem.

But... I have a few things to think about laser engraving of pictures.

Dirktheeng wrote a little article about laser power and the fact that you get peak power in a single pulse at about 2 or 3 ms in the shot.

But what about engraving ?

If an engraving head travels a distance of for example 20cm (200mm or 1000 dots if we try to engrave 5dots/mm 127DPI)

That 20cm distance will be done at quite high speed, say for example at 500mm/sec
That means the laser only has 1/2500th of a second time per dot.

Thats 0.4ms for 1 dot.

How on earth are laser engravers doing this? Are they setting the power at 100% and then giving pulses for 0.4ms ? or do they use other tricks to be able to fire the laser that fast ?

I do recall from Dirktheeng's information that the laser does start shooting faster then those 2 to 3 ms, but will it allready shoot after 0.4ms ???


Is there anybody who has information about this ? Maybe those people who have emc2 configured to engraving could explain? I suppose they will have timings entered into their software?


My purpose is to recreate a controller in a very very very cheap way using Atmel AVR controllers (but not arduino, since I want to program them at much lower level to get very tight timing profiles)


Any info on these timings/settings would be very valuable to me.

Kind regards,

Bart
educa
 
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Re: engraving timing and power settings?

Postby BenJackson » Sun Feb 12, 2012 7:09 pm

I'm sure my code is trying to pulse for tiny durations like that, and I don't know what really happens, although the engraving detail is good.

I have considered several ways to pre-process the image to take that sort of thing into account but I haven't really done that much engraving.
BenJackson
 
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Re: engraving timing and power settings?

Postby educa » Sun Feb 12, 2012 7:16 pm

Ben , is it somehow possible to know exactly the timings you have configured in emc ?
educa
 
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