On Wed, 14 Jul 2004 10:31:05 -0400, Esteban Arias <
earias@...>
wrote:
> Stefan,
>
> In the thermostat circuit, I placed a LED in serie with the LED of
> optocupler that drive the gate in the triac. I first power on the
> thermostat circuit and the LED is ON all the time, then, I power on the
> fuser with 220v and the LED begin to off and on slowly. Then, when the
> temperature in the fuser is 160 degree app, the LED turn off and on more
> fast and then maintain the frequency of oscillating. I think that
> frequency
> is 2 cicles for second.
That is interesting. Your fast fuser seems to make this. With my big fuser
it is oscillations with about 1 cycle every 5 seconds or so.
Considering the controller is "syncronised" to the mains frequency (it can
only
turn on/off complete halfcycles) 2Hz oscillation is very OK. you will not
have any
variation in temperature there.
>
> I placed the temperature sensor of my multimeter in the teflon surface of
> fuser and adjust the temperature to 160ยบ with the variable resistor in
> the
> circuit.
I do the same. use a small amount of thermal compound on your temp. sensor
or you must wait long until it is heated up. also it is more accurate with
thermal compound. (But the small error doesn't count in this application)
>
> The main problem with the unit is the number of pass for the pcb. I roll
> slowly the fuser with a bipolar stepper motor but I need to pass 20 times
> the pcb for obtain the result in the photo. With this pcb, I tested to
> pass
> only 10 times the pcb, but not work, I ever need 20 o more. Maybe the
> paper
> type?, maybe the roll velocity of the fuser? or the temperature?
Tell me which PCB material you use (1 or 2 sides, thickness).
How thick is your paper? (estimate by comparision to known office paper).
How fast is it moving?
I will clock mine later and tell you how slow it is, it needs 1 pass for
perfect results,
two or three if you want to make broad traces (pinholes).
I believe 1 very, very slow pass is more eficient, because the board
doesn't cool
between passes.
Maybe you also should use 180 degree, i'll measure mine again in about a
hour and tell you.
I think it depends on the toner make too.
I assume you pass it with the paper facing the heated roller, not the
rubber one.
ST
P.S.: You really want to try component legend next time, i'll write up a
howto soon.