Homebrew PCBs

Alan, no offence, but has it ever appeared to you you might be a little 
crazy? ;-)

Don't you think the automated feed is a bit of overkill....?

Do you really cut boards yourself this way?
Don't misunderstand me - your plan is interesting and all, but somehow it 
sounds like some "nutty professor machine".

There are CompactDisc size 1mm blades for the angle grinder.
Maybe they are a option too - but i still like carbide blades more.

Also think about gravity feed. A piece of string, a pulley and a weight
may be much easier to set up than a stepper. With that you have constant 
force
no matter which material thickness you have. (I used this with hot-wire 
foam cutting - couldn't get it working properly without).
see i can think of quite crazy contraptions too...

Stefan

On Sat, 20 Dec 2003 18:35:11 -0500, Alan King <alan@...> wrote:

> javaguy11111 wrote:
>> Any suggestions on cutting circuit boards. I have used a bandsaw, but
>> it tends to be slow, dusty and inaccurate. I have tried paper shears,
>> but the board tends to get warped and is only good for about two
>> inches and it is too hard to cut any further.
>>
>
> Dremel, really requires the flex shaft to do it so the handle can be 
> within the diameter of the cutoff disc.  Use the THINNEST discs, they 
> will break a bit more often but are cheap and cut faster due to less 
> material removal with the same power from the tool.  Actually use the 
> cheap $20 hand tool from Walmart, it's amazingly high quality for the 
> price and will also take the dremel flex shaft.
>
> Get two of the high quality drawer slides from Lowes ($15 or less). 
> Remove the outer 3rd section and just use the inner more bearinged two 
> sections for less play, requires drilling holes in the middle piece for 
> mounting though.  Mount a piece of wood between the rails, and tool to 
> the wood with hose clamps.  Align accurately so that the rest of the disc 
> travels exactly through the slot the edge cuts and the discs will last 
> longer than you'd think.  Set it up so you can mount the boards securely, 
> and have the tool travel on the rails and slice the board. Then, build a 
> simple stepper motor controller and attach a 1/4"-20 threaded rod to the 
> shaft, a coupling nut to the board, and set it up to travel automatically 
> at a reasonably slow rate.  Adjust speed to have a reasonable rate 
> without too much loading on the tool.
>
> Coat hanger wire.  Build a box frame around the whole cutting area, but 
> not the dremel motor.  Point the wire ends in so they don't cut the bag.  
> Wrap a garbage bag around the frame with the sliding tool plate moving 
> along a slit in the bag.  Knock your boards off before removing, and 
> throw the bag away now and then to get rid of the dust.  A design that 
> keeps the rails and the flex shaft handle (bearings) outside the bag will 
> be best.  Helps if you hunt down some good clear bags, although you can 
> flip the front up when loading a board easily enough.  Small slits in the 
> bag don't let out too much dust, one on the other side will let you get a 
> hand and screwdriver in for changing the wheel etc.
>
> Note that this can be scaled up to more drill sized cutoff wheels and 
> motor systems.  But you still want to seperate the boards not grind a 
> bunch of fiberglass dust, so the thinnest wheel you can use will be the 
> best.  Anything more is just wasting grinding wheel money and making more 
> dust.
>
> Actually just thinking more about it, some spring snap clips like the 
> ones to hold tool handles on the wall but small enough to hold the flex 
> shaft may be good enough to let you pop the handle in and out so it's not 
> tied to the machine.  If not that some other quick removal system would 
> be a good idea, no sense having a dremel and flex sitting around for a 
> single purpose if not necessary.
>
> Maybe $80 or so if you have to buy the tool and flex which will come in 
> handy anyway.  Only does straight cuts but could be modified for more, 
> and worth it if you do more than a few boards.
>
> Alan
>