Re: [CAD_CAM_EDM_DRO] More info?

On Wed, 06 Aug 2003 17:46:56 -0000, you wrote:

>Thank you all!!!!!!!!
>Wow guys know ur stuff.
>
>About the accuracy....simple PCB drilling... simple meanng...single
>sided drilling of prevously etched boards...no milling. Sorry if i
>seem thick bt i dont know what is meant by "traces" but im sure my
>machine will be as simple as possible.

Traces are the little tracks of copper on the board that serve as
wires. Pads are the little donuts of copper that a part lead goes
through and is soldered to...

>
>I have previously taken the chance to order allegros ucn5804b as
>samples and i have them here, all i need now is a circuit diagram
>that will enable me to attach these between parallel port and
>steppers without blowing the computer up!!>??

Get their application notes, all of them are free.

Consider an optical isolator, go look for one with a transfer ratio of
100% (6N35, IIRC) will do. Wire it up with an isolated power supply
to the parallel port... remember that parallel ports like to sink
current, not source it...

The other end of the optoisolator drives the stepper chip.

5000 volts isolation..... computer is safe....
power supply can be 5.0 volts at 100 to 200 ma, roughly....

>
>
>Also with regards to access to machine tools..i have use of a
>university machine shop and woodworking room. the technician can hep
>and i myself have a resonale level of skills as in one year, i will
>be in schools teaching children the basic concepts of resistant
>material cratfsmanship as a technology and design teacher

That's good. You can use wood, aluminum plate, fiberboard (Medium
density is good)... whatever works.

>
>With regard to the drawer slide...brilliant idea...seen it done on
>some of the websites, however..it does look very "simple" for want of
>a better work.
>My project must appear to be one of great technical appearance to
>ensure a decent mark..(year three which i have just completed, i
>average 76% which is a borderline 1st class HONS, therefore i realy
>need something that can blow tem away to move me away fromthe border
>towards a more certain 1st class. IF u know what i mean?

If you can find any linear bearings (they're expensive), you can use
them

You can make a good table with roller blade bearings (cheap tube of 8
or 16 ought to be about 10 pounds sterling or so)...

piece of square tubing can be the rail it runs on.

Go to www.netcom.com/~madyn and click on electronics, and look at the
xyzr table, both parts... Might give you some ideas....

>
>My work must be relective of a final year degree student studying an
>honours level degree. Also i cant do a wee machine and then
>improve..time doesnt allow...must b good 1st time (hence be calling
>on experience) and i cant really afford to do it wrongly as if ir
>dont work....i fail...dont pass exams...dont teach.

This design works, but may be too complicated... however, ideas might
help.

Harvey

>
>On that note..thanks again for the help
>Sammy
>
>