[Robotgroup] laser cutting (was: cardboard bots)

[Glenn Currie]

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

Leslie Filip <lfilip at mac.com> wrote: 
On 16 Jun 2008, at 11:19 PM, Robert Carter wrote:

>
> On Jun 15, 2008, at 3:59 PM, brooksdesign wrote:
>
>>   Does anyone remember who we got the cardboard bots from? I have  
>> a product that I need a bid on cardboard cutting and I figured I  
>> would go with someone who has helped us out. But if anyone knows  
>> of a laser shop or what ever there is locally......?????
>> -brooks
>>
>
> Hey Brooks--
>
> Sorry I didn't follow up on this yesterday, too busy to read my TRG  
> emails. But yes, I know of a laser shop, sort of: the UT School of  
> Architecture has two laser cutting tables, one with a cutting area  
> of 24 x 48" and one with an area of 18 x 32". I have not used them  
> myself, but a few months ago I took the preliminary class that one  
> has to sit through before one can work with them. Normally SOA  
> staff aren't encouraged to use these machines, they're for the  
> students and faculty. But this being the time of the year when  
> almost nothing is happening at the school, it seems like the  
> perfect time to ask if I can try it-- except I suddenly can't think  
> of any two-dimensional shape I need to custom fabricate. But if  
> you've got a project, maybe this is my chance to do something with  
> those cool machines (even though I promised myself I would not  
> volunteer for anything until I get some of my current tasks  
> finsihed, but this is a special case).
>
> I know the tables will cut plywood, plastics and thin metals. I'm  
> not sure if they will cut cardboard-- I mean, I'm sure the lasers  
> will penetrate it, but whether the cardboard will cut cleanly  
> without burning, I don't know enough about it yet to say. But if  
> the cardboard bots were cut on a laser table, then I imagine it can  
> be done.
>
> How much material would you need to have cut? Our laser cutters  
> require that the cutting pattern be laid out in CAD, do you have  
> your designs in that format?
>
> Here's some info on the school's equipment:
> http://soa.utexas.edu/it/digifab/lasercut
>
> Regards--
>
> Robert Carter
> Visual Resources Collection
> School of Architecture
> The University of Texas at Austin
> rcarter at mail.utexas.edu
>
>
>
>
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Hi Robert,

Are you certain those machines will cut metals? Normally it takes a  
special (read much more expensive) laser to even etch metal directly,  
much less cut it.

Les


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