Trotech laser cutters.

[Steve Baker]

I've been talking to several laser cutter manufacturers recently. One of
them, Trotech lasers offered to do a test cut for me. I sent them an SVG
file of a part I regularly cut at the space from 1/4" plywood. This part
needs a little bit of etching and a lot of cutting - and it takes our
trusty laser about 3.5 minutes to cut (using 80% power and 2% speed for
cutting and 20% power and 100% speed for etching - as recommended, and
more or less what we have in our defaults for plywood). That's about 30
seconds of etching and 3 minutes of cutting.

They tried it on their 80 watt laser - and it took one minute and nine
seconds!

Since the job is mostly about cutting - this can't be due to faster motors
or better acceleration - it can only be down to laser power.

So if our laser is 60 watt and theirs is 80...how the heck can it be 3x
faster?!?

(Incidentally, the machine they used costs about $16k)

-- Steve

[Jerry Rutherford]

Light / Power is Logarithmic.

Askjerry... everyone else does.
Visit me online at http://askjerry.info
See my projects, video links, tutorials, and blog today.

 -- Steve


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[Steve Baker]

Eh?

A watt is a unit of power defined as one Joule per second - and a joule is
a newton-meter. That's not logarithmic.

Are you saying that the rate at which you can cut through wood with a
laser is a logarithmic function of it's power?

-- Steve

Jerry Rutherford wrote:
> Light / Power is Logarithmic.
>

> *Askjerry... everyone else does.*

> Visit me online at http://askjerry.info

> *See my projects, video links, tutorials, and blog today.*

-- Steve

[Jerry Rutherford]

Yes... when you go from a 25 watt to a 35 watt laser of the same type your cut time is just about halved, even though the power was not doubled. When you go from a 35 to a 60 it goes down by almost 2/3 give or take... I don't have a formula on it... but it is not (double power = half speed) as you might expect.

Askjerry... everyone else does.

Visit me online at http://askjerry.info

See my projects, video links, tutorials, and blog today.

[Steve Baker]

Well, the mystery of how the Trotech machine could be so fast has been
resolved.

The salesman sent me a photo of what it cut - and it's missing at least
2/3rds of the design! I doubt that it's any faster than our ULS machine.

I think they probably have a bad SVG importer - I'm trying to find out
whether they used Corel Draw or some nasty knock-off CAD system.

-- Steve

Jerry Rutherford wrote:
> Yes... when you go from a 25 watt to a 35 watt laser of the same type your
> cut time is just about halved, even though the power was not doubled. When
> you go from a 35 to a 60 it goes down by almost 2/3 give or take... I
> don't
> have a formula on it... but it is not (double power = half speed) as you
> might expect.
>

> *Askjerry... everyone else does.*

> Visit me online at http://askjerry.info

> *See my projects, video links, tutorials, and blog today.*

>
>
>
> On Fri, Mar 30, 2012 at 10:18 PM, Steve Baker <st...@sjbaker.org> wrote:
>
>> Eh?
>>
>> A watt is a unit of power defined as one Joule per second - and a joule
>> is
>> a newton-meter. That's not logarithmic.
>>
>> Are you saying that the rate at which you can cut through wood with a
>> laser is a logarithmic function of it's power?
>>
>> -- Steve
>>
>

[Matt Goodman]

I think the logrithimic speed behavior comes from the fact that radiated power goes like t^4, so given a linear scaled flux of photons, you shoulkd get something that seems logish.  

My 2 cents.  
--Matthew Goodman

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