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cutting kevlar with laser

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BlueMeanie445

BlueMeanie445

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Hi all.

Has anyone here ever tried to cut Kevlar with a 445nm laser or LD based laser before? A friend of mine is looking to cut 3/16 panels and would like to know what minimal power would be required to do this.

He wants to avoid using IR for its inherent dangers and a bulky Co2 tube is out. Would 1W-1.5W be enough for the job?
Speed is not an issue, but depth is. I have noticed with my 445 that it cuts quite deep depending on material and focus.

Any suggestions welcome.
 





No it wouldn't go through a 5mm kevlar panel. You would need a CO2 tube, but as you said you don't want it, dangers are minimal when in a controlled CNC environment, a lot safer than handling a 1W 445nm laser.
 
Asherz said:
No it wouldn't go through a 5mm kevlar panel. You would need a CO2 tube, but as you said you don't want it, dangers are minimal when in a controlled CNC environment, a lot safer than handling a 1W 445nm laser.
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It is for a DIY CNC, he just doesnt like the idea of invisible light. How much power would be reasonable? I ve seen that beams can be combined so any workaround you can think of will help.

Ive never tried to burn kevlar so this is where im at a loss when he asked.
 
If its just going to cut flat panels, it cold use several focused at one spot right?
 
Why doesn't he just use scissors? That's what bullet proof vest manufacturers do.
 
redhook said:
Why doesn't he just use scissors? That's what bullet proof vest manufacturers do.
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Hes into lasers too, so naturally he would like to replace those scissors. With other projects he was able to use red lasers, but this one is a challenge for a visible laser. Though it must be possible. I am waiting for a sample of the material as ive never handled the stuff and have no idea how much energy this would take.

Anybody even try burning the stuff? Does it melt like a polymer, or burn like something cotton based??
 
If you do end up using a CO2 laser, it should be noted that cutting kevlar with a CO2 laser produces cyanide.
(According to Sam's Laser FAQ)
 
BlueMeanie445 said:
Hes into lasers too, so naturally he would like to replace those scissors. With other projects he was able to use red lasers, but this one is a challenge for a visible laser. Though it must be possible. I am waiting for a sample of the material as ive never handled the stuff and have no idea how much energy this would take.

Anybody even try burning the stuff? Does it melt like a polymer, or burn like something cotton based??
Click to expand...

Ever hear of Nomex? Its a type of Kevlar that is used in fire resistant clothing (often mixed with regular Kevlar). This is another reason to just use scissors. And as was stated above (although with incorrect information, the ignition source makes no difference), Kevlar produces hydrogen cyanide when burned (among other harmful gases). From the Kevlar MSDS.

http://www.speedliner.com/Websites/bearcat/Files/Content/158508/6. MSDS-Kevlar.pdf

Kevlar¨ fiber is inherently flame resistant, but can be ignited (limiting oxygen index = 29). Burning normally stops when the ignition source is removed. Pulp and dust accumulations
may continue to smolder once ignited. Kevlar¨ fiber dust does not present an explosion hazard.
Burning Kevlar¨ produces hazardous gases similar to those from wool. These are mostly carbon dioxide, nitrogen oxides and small amounts of hydrogen cyanide, ammonia,
aldehydes, aliphatic hydrocarbons and other toxic gases, depending on conditions of burning.
Caution: If permitted to dry, pulp can become electrostatically charged during processing and handling. Electrostatic discharge may cause ignition of nearby flammable vapors. Close
package tightly after opening to retain moisture.
Extinguishing Media: water, foam, and dry chemical, CO2
Fire fighting instructions: Wear self-contained breathing apparatus. Keep personnel removed and upwind of fire. Wear full protective equipment (full Bunker gear).
Click to expand...
 
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Whoa, thanks guys. No wonder scissors are method of choice. I personally have never worked with the stuff and it did not even enter my mind to check the MSDS.

If it were a project of mine I wouldn't worry so much as I only do burning under strict ventilation. Ive read that materials burned with laser produce some extra chems. Not sure if thats correct, but better safe than sorry. That could have been a bad thing to look over.:spank:

Im going to try out a sample with extreme caution and see if this is at all possible with combined 445.

Im hoping 3W might do it, good thing these beams are flat :shhh:
 
I my self am making a CNC right now with a 1W blue laser for cutting thin plastics and decal etching. This is just for tuning, I'm installing a 60W CO2 laser for acrylic later :)
 
jbtm said:
I my self am making a CNC right now with a 1W blue laser for cutting thin plastics and decal etching. This is just for tuning, I'm installing a 60W CO2 laser for acrylic later :)
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Well that certainly falls under the 'go big or go home' ideology. I think hes just feeling out ideas, and wants to go with the least expensive. 60W would be a good way to go, but price, bulk, and the dislike of IR...

Ive tried cutting an opaque prescription bottle, at least 3mm thick and the 445 did quite nicely.
 
BlueMeanie445 said:
Whoa, thanks guys. No wonder scissors are method of choice. I personally have never worked with the stuff and it did not even enter my mind to check the MSDS.

If it were a project of mine I wouldn't worry so much as I only do burning under strict ventilation.


Im going to try out a sample with extreme caution and see if this is at all possible with combined 445.
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Hydrogen Cyanide kills in small quantities.

Hydrogen cyanide - Wikipedia, the free encyclopedia

A hydrogen cyanide concentration of 300 mg/m3 in air will kill a human within about 10 minutes. It is estimated that hydrogen cyanide at a concentration of 3500 ppm (about 3200 mg/m3) will kill a human in about 1 minute. The toxicity is caused by the cyanide ion, which halts cellular respiration by inhibiting an enzyme in mitochondria called cytochrome c oxidase.
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Tell him to get one of these.

laser_scissors.gif
 
Hope, he finds a non-toxic way to do that. Wow hydrogen cyanide? Thanks, I wouldn't have guessed that without reading this thread. If he want's visible a YAG laser will do it. Most industrial accidents involve Q-switched YAG lasers though. And as you said it's not in the budget.
 
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