Markus Zingg wrote:
> I honestly don't fully understand this question. Again, the chemicals
> are from Bungard. It's the "entry chemicals set" for their "Compacta
> 30" throughplating machine (which is btw. in a completely different
> league than my machine - IMHO ~8000$). This set is reasonably priced
> and because the Compacta 30 operates with 15 and 30 litter tanks as
> oposed to my machine (2 and 5 liters) the chemicals obviousely last
> longer. Everythnig (chemical wise) is included in this set. I also
> ordered replacement Anodes for this same "Compacta 30" model cause
> they are well suited for my machine also. I can....
From what I imagine, you have all the tanks close to each
other and you dip the boards in the appropriate order in
each bath. Obviously you must rinse between baths so that
the subsequent baths do not become cross contaminated at any
appreciable rate. I'm wondering how you do the rinsing. Do
you have the tanks near a water tap, and simply lift the
board from the process tank, wait 20 seconds to finish
dripping, move to the running water tap, rinse, wait another
20 seconds to drip, then proceed to the next process tank?
I am thinking of building my own processing tanks, but
wondering if its worth including the rinse tanks after each
stage. Like you I have managed to weld 3 mm PVC plastic
sheet (the gray stuff) and I bought a secondhand hot air
welder for this job. I also built a plastic sheet bender
using a hot element wire running a line in the middle of the
piece of particle board. I found it impossible to get
straight and neat right angle bends using only a hot air
gun. The best way to construct a series of small narrow
tanks is to divide a big tank into small ones by welding
dividers inside. In this way 10 or 15 separate baths could
easily be built with the least amount of welding and materials.
A two stage counterflow rinse stage would consist of two
tanks next to each other, the first tank (the tank you first
dip) has about 1" higher liquid level than the second tank.
The wall between the two tanks has a open hole so the first
tank pours into the second tank when its liquid level goes
above this hole. The second tank has an effluent hole about
1" below this level. If you are a bit interested in
counterflow rinsing then check out;
http://www.justoffbase-tools.co.uk/tools.asp?parent=1I2433P1056M0Theoretically a 20cm x 20cm PCB will need 100 mL of fresh
water added each rinse cycle to keep the concentration of
the second rinse tank 1/1000 of the process tank in a two
stage counterflow rinse system.
If 3 stage counterflow rinse is used the concentration of
the final tank is reduced to 0.005% or 50 ppm. Ok its clear
2 stage rinsing is more than enough for the job.
In your setup, is it possible to empty individual baths ? I
was thinking of welding small block of plastic to the tank
bottom and then tap a 3/4" BSP thread into this block for
screwing in a drum tap. Something like shown
http://www.justoffbase-tools.co.uk/tools.asp?parent=1I2433P1056M0My aim is to have then entire PCB processing equipment in
the one area so I can make a board without having to run
around over the place. By including rinse tanks I think it
will make the job easier to control. Would you agree ?