Homebrew PCBs

On Mon, 17 Apr 2006 01:44:24 +0200, Herbert E. Plett <cachureos@...>  
wrote:

> I believe that no 'square' is needed, only one perfectly straight header  
> side
>
> where to make the reference notch into, and not necessarily at the  
> middle. The
>
> other three can be ragged.
>
> This one side will be fixed 'flat' against the reference border, can be
>
> anything  (leading, trailing, side) as long it is 'fixed' relative to the
>
> printer (motion). This 'reference' has to insure the registration during  
> the
>
> print process, not the board. This reference is part of some sort of  
> tray that
>
> has to move through the printer with +-5 mil tolerance... here is the  
> quid!


Strictly speaking this edge does not even have to be straight.
It only needs the same two points to sit against the edge, so any concave  
shape would do, only a covex edge is forbidden.


About the tray, my plan is that this tray is a moving carriage,  
permanently situated on some guiderail and directly driven by the rubber  
rollers. This would ensure good positioning. It would need to be returned  
to the rear position after each print, maybe as simple as pusing agaist  
the motors with power off or maybe requiring a switch to take over control  
of the motor and run it backward with a simple driver.


This would need much more of a modification to the printer, but it it not  
hard to do with printers that have a metal frame and where you can remove  
the plastic case to have a free path.


This would basically create a flatbed printer, gantry style.
It would of course require a dedicated printer to modify.


ST