[Robotgroup] solder masks (was: laser cutting (was: cardboard bots))

[Glenn Currie]

My experience with the solder masks is several years old, and may
have involved some special deals offered when they were starting
up.  I am checking into the solder masks again for making a diffraction
grating telescope gadget.  I will keep you posted on the results.

The set up fees are as you stated.   I have been involved with projects
where the customer only wanted a small number of boards made.
We tried to tell them we could have a bunch more made for just
slightly more money, but they would not go for it.  They ended up
coming back twice about 6 months apart wanting additional small
quantities of the same board.  The ended up paying the max price for
everything, including the rush, rush fees board house charge for
really fast turnaround.

I have been buried firmware projects for 2 1/2 years and just getting
back to some hardware projects.  It seems the world has changed a bit.
We will see what good stuff I can get done before having to round up
a paying job.

cheers,

-Glenn

Leslie Filip <lfilip at mac.com> wrote: Glenn,

If you buy more than one solder mask of a given pattern the  
additional copies are cheaper. This is due to setup fees being tacked  
on to the first one. I understand what buying in volume can do, but I  
don't think Gray is talking about buying a few thousand of one thing.  
Gray, correct me if I am wrong here. However, I would be interested  
in your experience with the solder masks you say are 2 orders of  
magnitude cheaper than the $200 I mentioned. What size and quantity  
are we talking about to get them down to a few bucks each?

Les


On 17 Jun 2008, at 5:07 PM, Glenn Currie wrote:

> 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  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
>>
>>
>>
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