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Years ago I wondered if a Laser beam with shields above and to the sides of it could cut grass instead of spinning blades. I think I mentioned it on another forum years ago but I don’t remember the answers. I honestly don’t know much about Lasers.
 

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While it is theoretically possible, I doubt that any manufacturer would produce such a thing due to the potential for product liability lawsuits. A laser powerful enough to cut grass would be too dangerous. Consider the the laser pointer, which normally operates in the milliwatt range, and so cannot even cause paper to ignite, but it can cause permanent damage to the human retina. A laser powerful enough to cut grass at any speed that would make it competitive to spinning blades would easily cut through human flesh as well, and could easily be converted into a weapon.
 

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Put that on an electric rider and the neighbors couldn't complain about noise anymore.
And no more dull blades.. ?

Honestly don't think you'd ever see it.
 

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Light Amplification by the Stimulated Emission of Radiation, or laser for short.

While applications for lasers have come up by leaps & bounds, I highly doubt we'll see them being used for rather mundane uses like cutting the grass on residential or commercial properties anytime in your children's children future.
Contrary to what one sees in movies, lasers work by focusing the light output onto a specific item. An easy way to think of it is to remember how you may have once used a magnifying glass to focus the sun's light onto a piece of paper (or other) to burn a hole. The point was to concentrate that intense focus point, too far away or too close didn't work. The same with lasers. There also can't be anything in the way of the beam because that will block the unfocused beam of light. Think of laser surgery where they have to insert a optic fiber to where the laser will work. They can't just aim the focus through your body.

The fictional popular "light saber" is not a laser, but a directed energy weapon that has a defined visible component, two quite different things.
 

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Feasible or not, I don’t see how a laser is any more dangerous than spinning blades.
 

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Grass could be 'vaporized', so no clippings/thatch and completely enclosed cutting area.
No physical blade to encounter roots or other fixed objects.
No rotational momentum, so could stop instantly if field breeched.
No rotational force to throw rocks/objects.
Less potential for hazard in dry grass from sparks against objects.
 

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Feasible or not, I don’t see how a laser is any more dangerous than spinning blades.
That spinning blade stays within the confines of the mower deck (or is supposed to)....A laser beam goes forever. Just imagine, you are standing by your laser mower and the spinning beam hits your feet....."Look ma, I don't need shoes anymore"
 

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The point was to concentrate that intense focus point, too far away or too close didn't work. The same with lasers. There also can't be anything in the way of the beam because that will block the unfocused beam of light.
Not the same. Lasers are "coherent" light. All (or nearly all) of the light energy is sent out in a single beam that doesn't need to be focused because it doesn't spread out as it travels away from the source. As to anything blocking the beam, if it is powerful enough to cut grass and the only thing in its path is grass, it will cut through any grass in its path given enough time.
 

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That spinning blade stays within the confines of the mower deck (or is supposed to)....A laser beam goes forever. Just imagine, you are standing by your laser mower and the spinning beam hits your feet....."Look ma, I don't need shoes anymore"
A laser could easily be confined to the deck - think of a mulch setup.
 

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It cuts by burning. I imagine it could be a fire hazard in dry conditions, or with leaves or other debris that easily catches on fire.
 

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Feasible or not, I don’t see how a laser is any more dangerous than spinning blades.
In theory, the laser does not need to spin like a blade. It can be directed across the width of the cutting path.

Clippings would not burn up, They would simply fall as the laser moved past the particular blade of grass that was cut.

The problem is that the blade of grass being cut blocks the laser from adjacent blades of grass. If the laser is strong enough to cut a 20" swath, it's also strong enough to lightly erode the foundation wall of a house with each pass. What material can be used to stop it at 20" that won't also be eroded to the point that the laser escapes the confines of the "mower"?
 

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In theory, the laser does not need to spin like a blade. It can be directed across the width of the cutting path.

Clippings would not burn up, They would simply fall as the laser moved past the particular blade of grass that was cut.

The problem is that the blade of grass being cut blocks the laser from adjacent blades of grass. If the laser is strong enough to cut a 20" swath, it's also strong enough to lightly erode the foundation wall of a house with each pass. What material can be used to stop it at 20" that won't also be eroded to the point that the laser escapes the confines of the "mower"?
Glass, or a mower/vibration safe equivalent. And those grass blades cut loose would be cut and recut the same way a mulcher blade recuts them.

Thing with LASERs is that they can be tuned, so they could cut grass and similar organic materials but not metal. It's a matter of beam strength.

Or so, I've heard.
 

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Glass, or a mower/vibration safe equivalent. And those grass blades cut loose would be cut and recut the same way a mulcher blade recuts them.

Thing with LASERs is that they can be tuned, so they could cut grass and similar organic materials but not metal. It's a matter of beam strength.

Or so, I've heard.
If the laser is spinning, you are right. But how fast (or slow) does the laser need to spin to cut all of the grass in its path? Since a laser makes no wind, the grass will drop immediately after being cut and multiple beams at various heights would be needed to mulch the grass.

The same problem occurs with a spinning laser. As it cuts one blade, the laser is blocked from adjacent blades in its theoretical path. It's energy is expended on the first solid object in its path.
 

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Also remember that LASERs are use in surgery and all sorts of industrial applications, so the beam can be controlled and caught. It doesn't just continue on forever through other materials.

And of course, this is all casual conversation ... what if, type stuff. I don't ever expect to see it in practice.
 

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My guess is practicality/cost/effectiveness, etc, all factored in make it not worth it. A laser pointer is about 5mW. In the US I believe 500mW is maximum you can own legally. A laser beam on police or aircraft can get jail time.
Here's a video of a young man who made a 200 Watt laser. It can pop balloons, burn wood, etc., but cutting grass at mower speed I bet would take more power.


Years ago Lowe's had a riding mower I thought of buying. Extremely innovative I thought. A gasoline engine with a generator and each of the three mower deck blades turned by an electric motor.
So no belts, and generator would run your house if you had a power outage!

A riding mower still needs propulsion, so the tried and true gas engine which also spins the blades makes the most sense.

We will certainly see 100% electric mowers in our future. Clean, quiet, simple.

Sent from my SM-S320VL using Tapatalk
 

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Discussion Starter #18
I wasn’t thinking of a spinning Laser, but a fixed position one with shields on all sides accept the bottom.
I think those electric generator/mowers that were sold about 5 years ago had lots of problems and were discontinued.
 

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My yard as I'm sure most people's yards aren't golf course is far from perfect. When I cut grass, types of grass and thickness varies, then I hit twigs, small limbs, leaves, etc. When I'm through it looks great.
A laser can't do that. It doesn't need to spin, but moving along at a constant speed it would have to be able to cut through all that variety of stuff. The sticks, twigs and leaves rather than getting chewed up (mulched) would be cut with precision which you wouldn't want.
I thought about laser years ago also...but it's just not practical.
Total electric you'll see with spinning blades. No gas or oil to fool with, plug it in overnight and you're ready to go. Quiet, very little maintenance.

Sent from my SM-S320VL using Tapatalk
 

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In theory, the laser does not need to spin like a blade. It can be directed across the width of the cutting path.

Clippings would not burn up, They would simply fall as the laser moved past the particular blade of grass that was cut.

The problem is that the blade of grass being cut blocks the laser from adjacent blades of grass. If the laser is strong enough to cut a 20" swath, it's also strong enough to lightly erode the foundation wall of a house with each pass. What material can be used to stop it at 20" that won't also be eroded to the point that the laser escapes the confines of the "mower"?
As I mentioned previously, it would be confined like a mulch setup is.

As has also been mentioned, lasers don’t inherently zap through everything in their trajectory.
 
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