On Tuesday 27 April 2004 11:04 pm, Dave Mucha wrote:
> > > The benifit of mechanical etching is no chemicals.
> > > the down side is the expensive cutters that wear out quickly.
> >
> > I have the impression that this is more of a problem with some
> > board materials than others, is that the case?
> Yes, FR-4 is the most common and easiest to get. Seems no one knows
> were to get boards as the question on here rarely gets an answer.
That's what, that green stuff? Is there a FAQ about board materials
someplace? I saw phenolic referred to as well as FR-4, so I figured that
they were two different things. <g>
> But the phenolic boards are much gentler on the cutters, but it does
> not really matter if you can't get the darn things.
They've gotta be out there somewhere. Where ∗do∗ people go to get raw board
material? Only stuff I've gotten so far was an assortment pack at Radio
Shack, aside from some of their perfboards and such.
> > > A dull cutter will raise a burr on the copper and dependong on
> > > your hold-down method, will or will not effect the rest of the board.
> > I haven't yet begun to explore the possibilities of various
> > holddown methods.
> >
> > I can think of a few right off the top of my head, those being
> > simple clamps, some kind of a T-slot table (more clamps), or maybe a
> > vacuum holddown setup. What else is there?
> Duct tape. No, really.
Would that be flat enough?
> I have a pair of pins in the table the board slips over them for
> alignment and from there the boards is held on the edges with duct
> tape.
Ok.
> The drill does not lift the board and mechanical etching is held firm
> with the two pins.
I'm figuring on building a smallish table, and then putting another hunk of
material on top of that for "sacrificial" purposes, so I won't have to worry
too much about it.
> > > Another plus for the CNC is drilled holes.
> > Yes, that's a big plus in my opinion. I'd ∗much∗ rather have the
> > machine do that than have to do it myself...
> And THAT is why CNC-PCB_design was created !
Works for me!
> the non-technical, home brew drilling concept you can build from
> stuff laying around to spending $100.00-200.00 in parts.
And I have a ∗LOT∗ of "stuff laying around". Got a whole box of assorted
stepper motors scrounged out of various floppy drives and printers, more
transistors and chips than I want to think about, enough passive components
that I really don't think I'll need to buy any anytime soon, and more.
About the only thing I can think of that I might want that I don't already
have is a couple of good-sized hunks of threaded rod...