Question about PCB software (and making the boards at home)

larwe@larwe.com wrote:
>
> 
> It's superficially very easy, but the devil is in the details,
> particularly if you are trying to achieve a zero rework rate. For
> fine-pitch QFP, simply squeezing solder paste onto the pads,
> hand-placing parts and dropping the PCB into a toaster oven gives what
> I'd call "80/20 Pyrrhic results" - i.e. most of the time, 80% of the
> joints are good, but fixing the remaining 20% takes as much time or
> more as it would have to hand-solder the entire thing.

That's as I expected. My own production boards are also hand assembled 
(not by me), using a Wavetip for TQFPs, and I seldom get a failure. I 
think it's a matter of process scale- just as you wouldn't attempt wave 
soldering for through hole components at home (I bet someone has), hand 
assembly suits small quantity production best. Now for those NGAs....

Paul Burke

larwe@larwe.com wrote:
> Jet Morgan wrote:
> 
>>What is a toaster oven ?
> 
> 
> Talkie's the name, toasting's the game. Anyone want any toast?
> 
> It's a small front-loading electric oven, typically about 45cm wide by
> 25cm tall by 25cm deep (interior cavity) with heating elements at top
> and bottom. Cheap ones are under US$20 at department stores. Typically
> used for heating a grilled cheese sandwich or a mini pizza or similar
> fodder.
> 
Cultural differences- I haven't seen on over here- the sandwich toasters 
we get here squeeze the stack between two shaped hot plates, rather like 
a waffle maker. Not very good for PCBs.

Paul Burke

On Thu, 28 Apr 2005 09:05:39 +0100, Paul Burke wrote:

> larwe@larwe.com wrote:
>> Jet Morgan wrote:
>> 
>>>What is a toaster oven ?
>> 
>> 
>> Talkie's the name, toasting's the game. Anyone want any toast?
>> 
>> It's a small front-loading electric oven, typically about 45cm wide by
>> 25cm tall by 25cm deep (interior cavity) with heating elements at top
>> and bottom. Cheap ones are under US$20 at department stores. Typically
>> used for heating a grilled cheese sandwich or a mini pizza or similar
>> fodder.
>> 
> Cultural differences- I haven't seen on over here- the sandwich toasters 
> we get here squeeze the stack between two shaped hot plates, rather like 
> a waffle maker. Not very good for PCBs.

We do have toaster ovens in Europe.

It is the kind of thing you might have in a bedsit, caravan or holiday
home.

The ones I found in a quick look on department store websites were a bit
more than US$20 though.

Robert Swindells

> >>What is a toaster oven ?
> >
> >
> > It's a small front-loading electric oven, typically about 45cm wide
by
> >
> Cultural differences- I haven't seen on over here- the sandwich
toasters
> we get here squeeze the stack between two shaped hot plates, rather
like
> a waffle maker. Not very good for PCBs.

We have those in the US too - they're simply called sandwich makers.
Back home in Oz we call those sorts of crushed sandwiches "jaffles"
(see for instance
http://www.kookaburragas.com.au/foodware_jaffleirons.htm which is the
old-fashioned manual style). Mmmm... a piping hot ham, cheese and
tomato jaffle on wholegrain bread with plenty of butter - oh boy,
SOOOOOOOOOOOOO tasty. Haven't had one in close to fifteen years.

larwe@larwe.com wrote:
> 
>>>>What is a toaster oven ?
>>>
>>> It's a small front-loading electric oven, typically about 45cm
>>
>> Cultural differences- I haven't seen on over here- the sandwich
>> toasters we get here squeeze the stack between two shaped hot
>> plates, rather like a waffle maker. Not very good for PCBs.
> 
> We have those in the US too - they're simply called sandwich
> makers. Back home in Oz we call those sorts of crushed sandwiches
> "jaffles" (see for instance
> http://www.kookaburragas.com.au/foodware_jaffleirons.htm which is
> the old-fashioned manual style). Mmmm... a piping hot ham, cheese
> and tomato jaffle on wholegrain bread with plenty of butter - oh
> boy, SOOOOOOOOOOOOO tasty. Haven't had one in close to fifteen
> years.

Toast your bread, spread on the butter, add the ham etc, pop in
microwave for about 30 seconds, and you have it.

-- 
"If you want to post a followup via groups.google.com, don't use
 the broken "Reply" link at the bottom of the article.  Click on 
 "show options" at the top of the article, then click on the 
 "Reply" at the bottom of the article headers." - Keith Thompson

> > I'm working on a project (which I'll probably market as a kit) that
> combines a non-contact temperature sensor with a simple PWM controller;
> you hack it into a toaster oven to turn it into a reasonably controlled
> reflow oven. It can handle the full preheat - reflow - cool temperature
> profile.

A project along these lines was published in Circuit Cellar not too
long ago, I believe.  My recollection is that the author wasn't able
to get fantastic control over the thermal profile, but good enough
that he was happy with the results.  I think this would be a great
kit; keep us posted.  I think he used a thermocouple rather than
a non-contact sensor; your approach might work better though I
think it's the "thermal inertia" of the oven elements that's the
problem.

-Tom

Gunnar wrote:
> Hi all,
>
> I stumbled over an ad on www.circuitcellar.com about free PCB
software
> (http://www.pcb123.com/).
> I would like to have some feedback about this software from anyone
using it,
> possibly comparing it to other PCB software out there.
>
> My needs are simple, I am planning to build small projects for
personal use.
> On that note, how many of you are making your own boards at home? I
used to
> make boards 20-30 years ago, but at the time I used parts such as
> transistors and TTL ICs. Now with surface mount ICs it is scary
trying to
> make boards...
>
> My own thought is that it is better to have the boards made by a
> professional outfit.
>
> Thanks.
>
> Gunnar.

It's good enough for personal use. I used it.
The reason I chose it is that their PCB quotes are only half of others.
And they can mail you in several days. It's hard to find any big
company to take care of our personal-use boards.

I'll recommend it.

xg