[Laser] Contentof Laser Digest, Vol 77, Issue 1, LASER Cutter

[Dieter Palme]

It must be a very big batt!

300 ft lenght x 1/2" thickness x 1/20" cut = approx. 90 inch ^3 volumen
to melt, Fe -> 131 gr/inch^3 -> 11.8 kg Fe.

Heat of fusion (Fe) 14 kWs/mol, specific weight of Fe ~19 g/mol. 11,8 kg
Fe -> 620 mol, needed Power 620 mol x 14 kWs/mol = 8700 kWs. In 6 min =
360 sec, 8700 kWsec /360sec = 24 kWatt optical Power for 6 Minutes. The
electrical power for the laser must many times the optical power.

If the cut is down of 1/200" (a very sharp focus) the needed Power
decreases by 1/10. P -> 2.5 kW optical Power. Many kWatt's electrical
power also.

The efficiency of lasers differs from 3 to 40 %. For cutting is a stream
of oxygen helpfull the iron burns in O2-gas and produces additional heat
for melting.

This system should be possible. Not more then 5 kW for 6 min are needed.

Dieter - dl7udp -



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Gesendet: Dienstag, 1. März 2011 18:01
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Betreff: Laser Digest, Vol 77, Issue 1


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Today's Topics:

   1. Battery-powered LASER cutter could save car accident victims
      (bernieS)


----------------------------------------------------------------------

Message: 1
Date: Tue, 01 Mar 2011 11:40:45 -0500
From: bernieS <bernies at netaxs.com>
Subject: [Laser] Battery-powered LASER cutter could save car accident
	victims
To: laser at mailman.qth.net
Message-ID: <20110301164054.A73BC88011 at mailman.qth.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed

Does anyone here besides me think it's a bogus claim that this thing 
can "cut 300 feet of half-inch-thick steel in six minutes on a single 
(50lb) battery charge"?

-Ed


http://www.emergencymgmt.com/health/Beam-Life-DeviceCar-Accident-022511.
html

Beam of Life Device Could Save Car Accident Victims
By: Corey McKenna on February 25, 2011

Two students at Ball State University in Muncie, Ind., are working on 
commercializing a battery-operated laser cutter that could help first 
responders shave minutes off the time it takes to free someone 
trapped in a crashed vehicle. The students, Adam Odgaard and John 
Benjamin, say the device is quieter and generates fewer sparks than 
hydraulic cutters currently used by rescue workers.

The tool, dubbed the Beam of Life Device (BOLD), can cut 300 feet of 
half-inch-thick steel in six minutes on a single battery charge. 
Odgaard said he and Benjamin found that an average extrication takes 
nine to 15 minutes. Odgaard said the BOLD could be at least three 
minutes faster than that. A proposed backpack design could help 
rescuers get into tighter spaces than hydraulic tools.

The current prototype, a desktop model, was developed by Tim Bradley, 
an engineer at the Naval Surface Warfare Center in Crane, Ind. The 
next step is for Odgaard and Benjamin to secure funding to develop a 
smaller prototype in which the power supply fits in a 50-pound 
backpack connected to a wand that a firefighter could operate single 
handedly. The target weight for the device is comparable to the 
weight of similar tools on the market, such as the Hurst Jaws of Life 
line of tools, to which the BOLD is being positioned as an alternative.

"You have to be able to get the shears in there, and then when the 
shears are going it will work against you and tire out most of the 
rescue responders trying to cut through steel," Benjamin said. With 
the BOLD, "you don't have to create an entry for your cutters to be 
placed inside the vehicle."

The BOLD also does away with carbon dioxide emissions so rescue 
workers won't have exhaust from the device blowing back at them.

Odgaard and Benjamin, who both study entrepreneurship, expect 
development of a smaller prototype to take about six months. That 
will be followed by a year of testing and evaluation with fire 
departments. The BOLD could be available for purchase by the end of
2012.

In 2009, more than 8,600 people were involved in motor vehicle 
crashes that required extrication, according to the National Highway 
Traffic Safety Administration. That number has been steadily rising, 
according to Frank Pintar, a professor in the Department of 
Neurosurgery at the Medical College of Wisconsin. Pintar is part of a 
team that's studying how to improve extrication methods.

There have been instances, Pintar said, where firefighters have 
endangered themselves or each other while attempting extrications. He 
sees a place in the field for a device like the BOLD if it can reduce 
the likelihood of those injuries.

"I don't see this taking the place of the Jaws of Life," he said. "It 
sounds like it's obviously a quieter device, and it might work just 
as well as a Sawzall without the dust flying all over the place and 
that kind of thing."

One advantage of hydraulic tools is that they support portions of a 
vehicle being cut. "In extrication you can't just cut metal," he 
said, "because sometimes a crumpled [piece of] metal that you cut 
will collapse the rest of the car and you'll actually endanger the 
occupant or other firefighters by doing that. So a hydraulic device 
actually adds stability to a crumpled car as opposed to just cutting 
things away."

Hydraulic cutters and spreaders are useful, Pintar said, when an 
occupant's limb is trapped in some kind of sheet metal. Where the 
BOLD would be useful is when an occupant is trapped in a car without 
being entangled by metal. "Let's say you would cut all the A-pillars 
of the car and just take the roof off, and then extricate the 
occupant from the top of the roof," he said. "Then this device might 
come in handy, but essentially that's what a Sawzall will do as well."

Odgaard and Benjamin are not the only ones attempting to market a 
battery-powered rescue tool. Both Hurst and Milwaukee Electric Tool 
Corp., maker of the Sawzall reciprocating saw, market battery-powered
tools.
   



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End of Laser Digest, Vol 77, Issue 1
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