Homebrew PCBs

Hi,

got the little oven today i was talking about.
The initial plan was that i buy two so i can transplant the heaters all  
into one for more power.
In the shop i inspected the oven, and it looked like the heaters were a  
single unit (like a loop), because if i would wiggle one the other moved  
too. So i did not by the second one after all.

At home i took it apart first thing (of course) and found there are  
individual heater tubes but they are connected at one end by a solid wire  
tack-welded to connect them, so that's why they moved together. It would  
be no problem to add more heaters.

I'm not sure now if i should go and get another oven or not. Measured the  
temperature profile, and it is roughly 1C per second, a bit faster at  
first, reaching 220C in 140 seconds. I'm not sure now if i should buy  
another oven for the heaters or not.

Any recommendations?

ST

are 'spare' heaters more expensive than an oven out of the box?


--- Stefan Trethan <stefan_trethan@...> wrote:
> I'm not sure now if i should go and get another oven or not. Measured the  
> temperature profile, and it is roughly 1C per second, a bit faster at  
> first, reaching 220C in 140 seconds. I'm not sure now if i should buy  
> another oven for the heaters or not.


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On Wed, 16 Aug 2006 13:31:12 +0200, Herbert E. Plett <cachureos@...>  
wrote:

> are 'spare' heaters more expensive than an oven out of the box?


Most likely, but i wouldn't know where to get them.

The oven costs 19eur and has 4 heater tubes.

ST

Decided to buy it after all...
19eur and half an hours drive isn't so bad compared to the hassle of  
making other heaters fit if i would have to do that at some point.

BTW i metered the thing and it has 1000W not 1200W as the label says -  
another "we will put sticker" specification...

Anyway, 2000W will comfortably fit any outlet, and it will be an easy and  
very clean modification to double the power.


Now on to making a temperature control!

ST


On Wed, 16 Aug 2006 13:43:28 +0200, Stefan Trethan <stefan_trethan@...>  
wrote:

> On Wed, 16 Aug 2006 13:31:12 +0200, Herbert E. Plett  
> <cachureos@...>
> wrote:
>
>> are 'spare' heaters more expensive than an oven out of the box?
> Most likely, but i wouldn't know where to get them.
> The oven costs 19eur and has 4 heater tubes.
> ST

> -----Message d'origine-----
> De : Homebrew_PCBs@yahoogroups.com 
> [mailto:Homebrew_PCBs@yahoogroups.com] De la part de Stefan Trethan
> Envoyé : août 16 2006 12:55
> À : Homebrew_PCBs@yahoogroups.com
> Objet : Re: [Homebrew_PCBs] SMD/curing oven
> 
> 
> Decided to buy it after all...
> 19eur and half an hours drive isn't so bad compared to the hassle of  
> making other heaters fit if i would have to do that at some point.
> 
> BTW i metered the thing and it has 1000W not 1200W as the 
> label says -  
> another "we will put sticker" specification...
> 
> Anyway, 2000W will comfortably fit any outlet, and it will be 
> an easy and  
> very clean modification to double the power.
> 
> 
> Now on to making a temperature control!
> 
> ST


Stefan, that will make a total of 2000W for a unit designed for a max of
1200W.  Is the casing strong enough to withstand the extra heat?  Maybe
place a fan over it until you determine that it can take it, don't wanna
waste the sucker.

Robert
:)

On Wed, 16 Aug 2006 19:34:27 +0200, Robert Hedan  
<robert.hedan@...> wrote:

>
> Stefan, that will make a total of 2000W for a unit designed for a max of
> 1200W.  Is the casing strong enough to withstand the extra heat?  Maybe
> place a fan over it until you determine that it can take it, don't wanna
> waste the sucker.
> Robert
> :)


Well, the temperature will not change much, since it can reach soldering  
temperatures with the stock heaters.

I'm adding some to speed up the heating process, so SMD components are not  
subjected to an agonizingly slow and lengthy soldering process.

I will definitely not power it up with the built-in thermostat, since this  
does not measure baking chamber temperature but instead only the  
temperature in the electical compartment.

A LCD display will not fit the small space for controls on the right side,  
so i will probably put it in a separate electronics enclosure. Not bad  
because then it's out of the heat.


But now comes the nasty part - writing some atmel C software that allows  
me to run either a constant temperature or a timed profile. I really wish  
i wouldn't have to do that..
Nobody out there with the desire to make such an oven as well? I would  
provide PCB artwork for a universal controller board in exchange for  
software ;-).

ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@...> wrote:

> 
> But now comes the nasty part - writing some atmel C software that 
allows  
> me to run either a constant temperature or a timed profile. I really 
wish  
> i wouldn't have to do that..
> Nobody out there with the desire to make such an oven as well? I 
would  
> provide PCB artwork for a universal controller board in exchange for 
 
> software ;-).
> 
> ST
>

A PIC is a elegant solution, but this kind of controller can be made 
with an opamp, a comparator and a variable reference. For a timed 
profile you need only some logic ICs. 
Of course, the board will be a little bit larger...
If you want a computer controlled oven, I found somewere a little 
parallel port relay controller:
http://www.kemo-electronic.de/en/module/m125/index.htm
Everytime there is an analog solution as a "plan B" ;-)




Adrian

--- adicont2 <adicont2@...> wrote:
...
> A PIC is a elegant solution, 
...

I thought he talked about an Atmel ;)

(no, I am not starting an argument...)

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> ST wrote:
> But now comes the nasty part - writing some
> atmel C software that allows me to run either
> a constant temperature or a timed profile.
> I really wish  i wouldn't have to do that..

> Nobody out there with the desire to make
> such an oven as well? I would provide PCB
> artwork for a universal controller board in
> exchange for software ;-).

ST - I will gladly write the SW for you.

Atmels is what I do.

Just don't expect real fast turn around times.

> >adicont2 wrote:
> >...
> > A PIC is a elegant solution, 
> >...

> Herbert wrote: 
> I thought he talked about an Atmel ;)
> (no, I am not starting an argument...)

Bring on the Atmel/PIC holy wars I say.

I have faith the righteous will survive.

^ Nah, try this
get a module that comes with a forth interpreter and
control it from a laptop or desktop using a serial link.
for example, see NewMicros.com  As cheap as $29.
AGSC ^

On 2006-Aug 16, at 16:10hrs PM, Andrew wrote:

 > ST wrote:
 > But now comes the nasty part - writing some
 > atmel C software that allows me to run either
 > a constant temperature or a timed profile.
 > I really wish i wouldn't have to do that..

 > Nobody out there with the desire to make
 > such an oven as well? I would provide PCB
 > artwork for a universal controller board in
 > exchange for software ;-).

ST - I will gladly write the SW for you.

Atmels is what I do.

Just don't expect real fast turn around times.




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[Non-text portions of this message have been removed]

On Wed, 16 Aug 2006 22:56:17 +0200, adicont2 <adicont2@...> wrote:

>
> A PIC is a elegant solution, but this kind of controller can be made
> with an opamp, a comparator and a variable reference. For a timed
> profile you need only some logic ICs.
> Of course, the board will be a little bit larger...
> If you want a computer controlled oven, I found somewere a little
> parallel port relay controller:
> http://www.kemo-electronic.de/en/module/m125/index.htm
> Everytime there is an analog solution as a "plan B" ;-)
> Adrian


well, actually the analog solution is always plan A for me.
I just thought it will get too complicated with a soldering profile, but  
thinking about it that's not necessarily the case..
I will have to think about that - it would definitely be very tempting to  
throw something together in a matter of hours where it would take me years  
with an atmel ;-)
This could be done with a very simple state machine - 5 states: ramp up,  
soak, reflow, dwell, cool. That can probably be simplyfied into 3 states  
which are simple changes of temperature setpoint for a certain time..

Hmmm... you definitely got me thinking there...

ST

Stefan,
I sent you directly an article out of Circuit Cellar on a reflow oven FYI. Didn't want to get into the copyright issues by posting to the group.
Regards
John C

> -----Original Message-----
> From: Stefan Trethan [mailto:stefan_trethan@...]
> Sent: 17 August 2006 08:53
> To: Homebrew_PCBs@yahoogroups.com
> Subject: Re: RE : [Homebrew_PCBs] SMD/curing oven
> 
> 
> On Wed, 16 Aug 2006 22:56:17 +0200, adicont2 
> <adicont2@...> wrote:
> 
> >
> > A PIC is a elegant solution, but this kind of controller can be made
> > with an opamp, a comparator and a variable reference. For a timed
> > profile you need only some logic ICs.
> > Of course, the board will be a little bit larger...
> > If you want a computer controlled oven, I found somewere a little
> > parallel port relay controller:
> > http://www.kemo-electronic.de/en/module/m125/index.htm
> > Everytime there is an analog solution as a "plan B" ;-)
> > Adrian
> 
> 
> well, actually the analog solution is always plan A for me.
> I just thought it will get too complicated with a soldering 
> profile, but  
> thinking about it that's not necessarily the case..
> I will have to think about that - it would definitely be very 
> tempting to  
> throw something together in a matter of hours where it would 
> take me years  
> with an atmel ;-)
> This could be done with a very simple state machine - 5 
> states: ramp up,  
> soak, reflow, dwell, cool. That can probably be simplyfied 
> into 3 states  
> which are simple changes of temperature setpoint for a certain time..
> 
> Hmmm... you definitely got me thinking there...
> 
> ST
> 
> 
> Be sure to visit the group home and check for new Links, 
> Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
> 
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
> Yahoo! Groups Links
> 
> 
> 
>  
> 
> 
> 
>

I have no chance to win this kind of war ;-)
Atmel/PIC, for me is the same thing: few resistors, few caps, an IC 
and a hocus-pocus software. 
This hocus-pocus is totaly over my head... 
;-)


Adrian


--- In Homebrew_PCBs@yahoogroups.com, "Andrew" <andrewm1973@...> 
wrote:

>
> 
> > >adicont2 wrote:
> > >...
> > > A PIC is a elegant solution, 
> > >...
> 
> > Herbert wrote: 
> > I thought he talked about an Atmel ;)
> > (no, I am not starting an argument...)
> 
> Bring on the Atmel/PIC holy wars I say.
> 
> I have faith the righteous will survive.
>

On Thu, 17 Aug 2006 01:18:48 +0200, adicont2 <adicont2@...> wrote:

> I have no chance to win this kind of war ;-)
> Atmel/PIC, for me is the same thing: few resistors, few caps, an IC
> and a hocus-pocus software.
> This hocus-pocus is totaly over my head...
> ;-)
> Adrian


Adrian, you don't need to do anything, just finish your analog solution  
and laugh at the fools that are still struggling with their software ;-)

ST

> > Adrian wrote:
> > I have no chance to win this kind of war ;-)
> > Atmel/PIC, for me is the same thing: few
> > resistors, few caps, an IC and a hocus-pocus
> > software.  This hocus-pocus is totaly over
> > my head...
> > ;-)

> ST wrote:
> Adrian, you don't need to do anything, just
> finish your analog solution and laugh at the
> fools that are still struggling with their
> software ;-)

What - you can get an analog solution finished
in under 20 minutes (which is how long I guess
it would take to do an Atmel version)

On Thu, 17 Aug 2006 01:14:20 +0200, John Craddock  
<John.Craddock@...> wrote:

> Stefan,
> I sent you directly an article out of Circuit Cellar on a reflow oven  
> FYI. Didn't want to get into the copyright issues by posting to the  
> group.
> Regards
> John C


Thank you, got it, it confirms this is all getting way too complicated.

Adrian has thankfully pointed out my folly and i will look into an analog  
solution.
I believe it should be fairly easy to do, and has many advantages for me.

You see, several people have offered to help with or even make the  
software completely, which is great, but the problem is i would still have  
to understand it to allow me to make changes, repairs etc.. If i can avoid  
software alltogether i would much prefer it. I will let you know with what  
i come up with, and if an analog solution is not practical i will have to  
reconsider using a micro.


ST

--- Stefan Trethan <stefan_trethan@...> wrote:
...
> Thank you, got it, it confirms this is all getting way too complicated.
> 
> Adrian has thankfully pointed out my folly and i will look into an analog  
> solution.
> I believe it should be fairly easy to do, and has many advantages for me.
...

I believe that if you have an oven with a knob that quickly and accurately sets
the temperature then in a DIY environment it's not hard to do the 'profile' by
hand (with a stopwatch). The whole cycle for each batch is only a few minutes
anyway and can be adapted on the fly by watching through the door.

pls keep us informed of this efficient controller...

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On Fri, 18 Aug 2006 01:22:13 +0200, Herbert E. Plett <cachureos@...>  
wrote:

>
> I believe that if you have an oven with a knob that quickly and  
> accurately sets
> the temperature then in a DIY environment it's not hard to do the  
> 'profile' by
> hand (with a stopwatch). The whole cycle for each batch is only a few  
> minutes
> anyway and can be adapted on the fly by watching through the door.
> pls keep us informed of this efficient controller...


Actually, i think you are right!
I don't need an automatic timed control at all.
I mean, let's be realistic, i will stare into the oven in anticipation  
anyway while i solder something and i don't plan on doing lots and lots of  
boards any time soon.

So a simple controller that is set with a pot and has a temperature  
display would be all that is needed!


I'd say KISS is the right thing to do here, and get it finished today....

ST

>I believe that if you have an oven with a knob that quickly and 
>accurately sets the temperature then in a DIY environment it's not 
>hard to do the 'profile' by hand (with a stopwatch). 

Well, I wouldn't put it so delicately...Most of us know you don't 
need much more elaboration than what you've stated in a homebrew 
scenario. Stencils Unlimited has been pushing the simple toaster 
oven concept for quite sometime in order to sell their stencils;

http://www.stencilsunlimited.com/prototype_stencils.php
http://www.stencilsunlimited.com/ovens_profiles_new.php

Instead of using temperature markers, some just look for when the 
solder melts like these guys;

http://www.seattlerobotics.org/encoder/200006/oven_art.htm

--- In Homebrew_PCBs@yahoogroups.com, "Herbert E. Plett" 
<cachureos@...> wrote:
>