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

Tue Jun 17 21:56:39 PDT 2008

Paul,

Good to know about.  There are many interesting uses for LASER cut
stencils besides their intended use.

-Glenn

Paul Atkinson <pmatkinson at gmail.com> wrote: Just in case anyone is actually looking for lower cost solder stencils,
Pololu.com has a service where they laser cut solder stencils from plastic
at a lower cost and lower precision than metal stencils.
http://www.pololu.com/catalog/product/446

Paul

On Tue, Jun 17, 2008 at 6:40 PM, Glenn Currie  wrote:

> 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  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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