[Robotgroup] laser cutting (was: cardboard bots)

[Glenn Currie]

I have not used the LASERS at the UT Architecture Department
or one used to cut solder masks.   None of my LASER pointers
will burn anything but a patterns  in live retinas.   

Although they will project a ~ 3' wide pattern on the downtown
Round Rock water tower from ~4,600 feet.  Harbor Freight night
vision goggles are needed to see the reflection.   For those interested,
I suggest doing these type experiments at night, as night vision scopes
are of limited use in daylight.   A solid optical mount is needed for
both LASER pen and the night vision scopes.   I have found that a 
fire place chimney will do.   Also, when conducting such experiments,
tell a couple of friends you are developing a lunar LASER ranging
device, so if the Williamson County police arrest you, it can be 
explained to them that you were just calibrating your instruments
before an observing run, and not an evil terrorist with plans to blow
up an empty water tower with a Wallgreens combo ball point pen/
LASER pointer, from almost a mile away.  

Landmarks like the Round Rock water tower are prime symbolic
targets for terror attacks.   I know I have strong feelings about
vigilance and Homeland Security.  Austin, being the state capitol
and the state the current president is from, makes our area a prime
target terrorist target.   In the downtown area it is hard not to get
your hair mussed due to the constant helicopter over flights,
especially around the capitol area.   

By the way, anyone hear if they figured out who threw the Molotov
cocktail on the porch of the Governor's mansion?   I wonder if the
effectiveness of the security cameras was reduced by all the dust
stirred up by the security aircraft?

I hope they get is all figured out so the Round Rock water tower will
be safe.

Solder masks come in different sizes, the ones I have seen were
two orders of magnitude less expensive than the ones you have
experience with.

Lots of details.  Some are important.  Check your time and credit line
limits before getting too deep into any project or you may end up
with only the data of the time and credit line part of the experiment.

-Glenn

Leslie Filip <lfilip at mac.com> wrote: The solder masks are done on a different kind of laser than what is  
over at the UT Architecture Department. Solder masks start at a few  
hundred dollars, so I would suggest it is more an economic issue than  
a technical one to make art with the same tools and techniques.

Les


On 17 Jun 2008, at 1:53 PM, Gray Mack wrote:

> With thin durable metal, we could probably make some cool art,  
> models, beam robots, a robotgroup logo paint template, etc using  
> that method.
> Any idea of cost per square inch?
> Is the metal more bendy or springy?
> -Gray
>
> --- On Tue, 6/17/08, Glenn Currie  wrote:
>
>> From: Glenn Currie 
>> Subject: Re: [Robotgroup] laser cutting (was: cardboard bots)
>> To: "The Robot Group Mailing List" 
>> Date: Tuesday, June 17, 2008, 11:57 AM
>> There are companies that make thin metal solder masks for
>> circuit board fabrication.  For surface mount parts, you
>> send
>> in a CAD generated solder paste mask and they send you a
>> LASER cut metal solder mask.  You lay the solder mask
>> over the circuit board and paint the exposed areas with
>> solder paste.  The solder paste serves to hold the surface
>> mount
>> parts in place before the solder is heated.   You remove
>> the
>> mask apply the parts - by hand if you are doing prototypes,
>> then baked the board and chips in a toaster oven at the
>> temperatures
>> the solder past is designed to work with and the solder in
>> the
>> paste liquefies and solders the surface mount chips to the
>> board.
>>
>> The mask can have arbitrarily complex patterns, the LASER
>> does
>> not care.   The masks are not real expensive and can be
>> reused
>> because they are durable metal.
>>
>> You could send in "art" if you wanted and get
>> them to cut you
>> a metal mask.  Just learn how to generate the CAD files.
>>
>> -Glenn
>
>
>
> _______________________________________________
> Robotgroup mailing list
> Robotgroup at puremagic.com
> http://lists.puremagic.com/cgi-bin/mailman/listinfo/robotgroup

_______________________________________________
Robotgroup mailing list
Robotgroup at puremagic.com
http://lists.puremagic.com/cgi-bin/mailman/listinfo/robotgroup