| ??? 05/04/09 09:50 Read: times |
#165032 - Chico might care Responding to: ???'s previous message |
Richard said:
I don't know about your DIY experience, but the fellow I mentioned, for whom I built the deflection system for his laser soldering machine, also built a laser with which he cuts 5 cm thick deck steel. The other one who owns the laser engraver company built his CO2 laser in his basement. It quite easily cut into the concrete foundation of his basement. I doubt the power was limited to any small number of mW. What is your point? That all the examples you mentioned where XY systems to allow the laser energy to target a known position? That they built their own solid-state or gas lasers? That they bought lasers at a time when the regulations did not stop people from doing it? That they worked with lasers that requires modulation of the light beam? That they needed to ask on forums? Do you recommend Chico to build his own flash or diode-pumped gas or solid-state laser device? What is your view on precision-machining - an argument used by you several times in this thread? Another thing: I work as an RD engineer. At what point will things I do become DIY projects? Many home projects presented on the net (laser projectors, surface-mount owens, digital oscilloscopes, ...) are designed and built by people who do similar things for their living. They obviously present what they have done on the net - they do not come visiting forms to ask how to do their normal work. So DIY discussions on web forums are normally about "normal" people trying to build "normal" equipment at less-than commercial-grade levels. Since it's possible for someone to build a kW-size laser, I assume anyone determined to do so can, as well. The observation that I've made of my hand-held laser pointer projecting a spot on a wall 100 meters away suggests that a very-low-power laser source can do quite a bit, and from that I conclude that a rasterized display is inherently possible, perhaps with a bit more power than the 5 small 3V lithium batteries in my pointer will produce, but certainly not requiring kW. And did you make your observations when keeping the pointer still or when moving it? A 256x192 display rendered on a 256x192 mm surface at 30fps has a movement rate of 256*192*30 mm/s which corresponds to 1.5km/s or 5300km/h (3300 mph). Would you still consider the dots easy to see at that sweep speed? That sweep speed - in relation to the number of fps - is the reason why each of your pixels will pick upp 1:50000 of the optical energy emitted by the laser. Of course, you don't need kW. You would get a stunning 100" image 3x5W optical output. In a dark room, 3x500mW would give a decent image. If you accept the high-precision work, you can stack 3 200mW diodes from DVD burners if you have half-reflective mirrors. A vector projector can produce stunning output with a 5mW green laser - available over disk and legal. Richard said:
Since the error in a 2-axis positioning system is a function of the product of the precision Did you miss tht the two mirrors are at 90 degree angle? Their errors do not multiply. And an absolute error in the mirror will move the image sideways or change the size of the image. It's certainly easier to construct a system with only one degree of freedom, rather than two. Changing to a rotating mirror does not change to one degree of freedom. You have just changed how to produce that degree. You must run the mirror at known speed and synchronize every scanline with the angle of the mirror. Richard said:
BTW, If you think that text display is so trivial, try that with your stroked method. I doubt you'll find it easy. Keep in mind, too, that anything that can be done with text can be done with bitmapped graphics as well. Of course it doesn't matter what it displays. A text-type of display normally has way higher dimension in one direction, and what matters is that the limited vertical resolution of the CC display reduces the total number of pixels - that does affect the intensity, since the scan speed can be much lower, or the refresh rate much higher. And if you want to spend time with machine tooling, you can run 16 lasers above each other. So many posts in this thread, and you still havent't picked up on (or comment once about) intensity? Mental blanking active? |
