Hi FusionITR,
I have gained quite some experience manufacturing plated through hole PCBs.
The device I used was developed by Isel automation. There are four baths necessary for the prepared PCB:
- cleaner
- activator
- another cleaner
- electrochemical copper plating
The PCB has to pass each bath at an exact temperature and an exact time period. A rocker takes care of removing trapped air out of the drill holes. (Otherwise they won't be plated.)
When a PCB is finished the first time it looks like being made by a commercial PCB manufacturer. Leaving the plating liquid in the tank it will become unusable after a few hours, creating a sponge like copper layer and huge build ups of copper at the drill entries (both sides, leaving the center to scale). Using through holes to place parts will result in extra drilling - most probably removing the entire plating. (See attachment)
This stuff is the most expensive part of all chemicals to use.
PCB material:
This method requires differential etching, meaning PCB material with 5µ copper layer is used. The film must be a negative image of your PCB design.
The exposed and developed PCB has to be covered with special self adhesive tape without leaving any air trapped between the tape and the PCB surface.
When this is done all drills have to be made (not to forget one!)
Finally the tape is removed and the PCB rinsed thoroughly with denaturated water, which it prepares for through plating.
All drills and the copper traces on both sides receive a copper layer of approximately 35µm. After etching the trace copper layer will have been reduced to 35µm (5µm on the base material +35µm electrochemical copper layer)
I found out that commercial PCB drill holes never meet the center of a pad. I did drilling manually with the drill hole exactly in it. (General accuracy of commercial PCBs is 0.025mm which might suffice, but never looks good.)
I doubt the machine you intend to buy will have the repeated accuracy. The photo was not clear enough to see what kind of drive spindles are used.
You could use the chassis and mount your own precision spindles, reduction gear (tooth belt) and stepper motors to it.
Last not least photoresist PCB material is as accurate as the film you use. A laser print is by far not sufficient for fine traces. I got my films made using a Gerber printer in a near by print shop. The finest trace width used was 0.245mm and none of them was underetched or missing.
From my experience BUNGARD has the best quality PCB material in Germany. Storing the material in a dark, cool place it's still well usable after one year. The photoresist layer is superb and of equal thickness all over the surface which guarantees sharp contours.
For PCB material look up: http:
Bungard Elektronik
As far as SMD soldering is concerned I go along with 3v0. Distributing the solder paste in correct doses is the "A" the "O" of SMD soldering.
Regards
Boncuk