--- In
Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
>
>
> Stefan Trethan <stefan_trethan@...> writes:
> > So what? Just because it has mass it can't be controlled?
>
> The loop is too big to be useful that way, esp when the initial
> ramp-up works just fine for reflow anyway. It's like a three MINUTE
> response curve. I'd rather invest my energy into something more
> responsive and leave this one alone.
>
If you'd rather save the effort for something more to your liking that's perfectly ok, however there's really no particular hurdle to overcome with what you have, it doesn't matter how much thermal mass it has or how long it takes to heat and cool, the temperature can be very accurately controlled. Something more responsive will be hot and ready to go much quicker, but it's also harder to regulate the temperature. Less thermal mass means more prone to oscillation above and below the desired temperature, and it will be more greatly affected by external influence. It can still be done, but it's harder, you have to substitute the mechanical thermal mass with electrical damping.
To illustrate the point, think of why your car has shock absorbers. They are mechanical damping to slow down the response of the suspension, without them you would be bouncing all over the place on the springs. You might notice that when you have the added mass of several passengers and cargo, the car rides smoother as well, the response to variations in the road surface is slowed.