mark lewis wrote in a message to Roy J. Tellason:

 ml>> ummm... some years back, i was highered to install and set
 ml>> up a series of CAD/CAM workstations for an engraving
 ml>> company... i don't remember the language spoken between the
 ml>> CAD and the CAM but i believe it was DXF...

 RJT> That sounds familiar,  I believe it's the name of a file format.

 ml> i know the files are something.dxf... and i used to look thru them 
 ml> when i'd export them from autocad... in a way, its almost like 
 ml> reading postscript...

Hmm.

 RJT>  There are also a couple of fairly standardized plotter 
 RJT> "languages" and some of the software that's out there will no 
 RJT> doubt provide those as output.  Or a plotter driver will.

 ml> yup... the thing is that it would be part of the DIY aspect, 
 ml> wouldn't it? somehow, you'd have to code something that told the 
 ml> system that x=+1 might be to move the x access in the positive 1 
 ml> step... its been a while since i dabbled in engineering areas... i 
 ml> forget, at times, about computers talking to computers for some of 
 ml> this stuff... it could be as simple as that x=+1 causing a pulse 
 ml> on one pin of the parallel port and that pin being cabled to the 
 ml> positive side of the x axis motor...

Nah,  I'd think you would want a bit more intelligence in the thing than
that,  but that's not hard to do with even an 8-bit processor.  Or throw an
old MB at it,  with a custom-burned eprom in there.  But that's probably
even more than you'd need.

 ml> i'm getting into some of this type stuff with telescopes and 
 ml> computer controlled tracking and positioning and such...

Seems to me I remember reading that this was why the Forth language was
first written.  I have an implementation of it here but never did anything
with it.

 ml> seems to be very similar... two motors for guidance and there's 
 ml> also some new stuff working for a third motor in the mix to 
 ml> eliminate having to align the scope in the traditional ways...

I never got into any of that.  I expect that there would be some stuff in
common,  though.

 ml>> in any case, the CAM platform was fixed in place and you anchored 
 ml>> the flat material to be engraved... the engraving stuff was 
 ml>> basically little more than the (old style?) "moving cross" 
 ml>> flatbed plotter movement with a dremel type tool attached to a 
 ml>> z-axis for automatic height adjustment and precision control 
 ml>> instead of the pen-up and pen-down type stuff...

 RJT> Y'know,  I have a dremel tool and the thought never occurred to 
 RJT> me that it might be a thing to use for this.  

 ml> it might... though i've burnt up a few simply by using them for too
 ml> long in a session...

Mine does get pretty hot.  Maybe applying somewhat less power to it would help.

 RJT> Mine is an older model for which the common accessories are no 
 RJT> longer available,  and i was lucky to be able to find collets for 
 RJT> it,  all four of them.  But somebody pointed me to a source where 
 RJT> I could buy a "drill press" setup for it that was made by a third 
 RJT> party.  Perhaps something like that would be useful,  adaptable 
 RJT> to this sort of thing.

 ml> cool...

The unit was available at Lowe's,  if you have one of them around you
somewhere.  I never did look at it too closely,  just went in and asked the
guy if I could bring my dremel in and see if that'd work with it and he
said yeah...

 RJT> I hadn't envisoned much z-axis motion being necessary,  do you 
 RJT> think I'd need much?  And precision in it at that?

 ml> sure... think about etching "relief" art (i think that's right)... 
 ml> basically, you don't want to just drop the cutter head right into 
 ml> the material... you'd want to ease it in to the proper depth...
 ml> depending on the material, you may need to make several passes 
 ml> with each being deeper than the last... and what i was thinking 
 ml> about "relief" art was along the lines of small sculptures or even 
 ml> being able to work with material that's not flat...

Ok,  so I guess some vertical control and motion are going to be necessary.
 But not all that much.

 ml>> the stuff came with its own CAD package but these guys already 
 ml>> had autocad and just stayed with it...

 RJT> Probably a lot more to it than the one that came with the machine.

 ml> autocad is/was the bee knees when it came to cad software... i 
 ml> don't know what the current leading package is, these days... i got
 ml> a copy of v2.1.1 some 15+ years ago and it was $3600+ at that 
 ml> time... even then, it did wireframe 3d stuff...

Yeah,  it's pricey.  Does it still require a "key" to operate?  I
have some other programs of that sort around,  but never really dove into
them that much.

 ml>> this is why i believe the the talk between the CAD and the CAM 
 ml>> was dxf...

 RJT> Yeah.  You mentioned something about engraving?  Was that what 
 RJT> they were doing with it?  My thinking was along the lines of 
 RJT> circuit boards,  machining rather than etching, and perhaps the 
 RJT> drilling,  and maybe some other things.

 ml> the ones that i was working with were doing plaques and trophys...
 ml> name plates and such... 

I've seen those setups,  somewhere.  They don't look all that complicated
or expensive,  either.

 ml> hey could etch many materials but metal and wood were the most 
 ml> common... though i did see them working on getting the movement 
 ml> speed right for working with solid blocks of plastic some company 
 ml> wanted something done with...

Plastics of one sort or another would seem to be a logical choice for this too.

 ml> AIR, something about "reverse etching" such that everything was 
 ml> mirror imaged and what would normally be etched out was left as 
 ml> raised material...

Sounds time-consuming.  Unless you had software that could cope with a
number of different-sized cutters.

 ml> basically like making a stamp or mold or something... once they 
 ml> got the prototype samples done, they were looking at processing 
 ml> orders of 10000 lots or more...

Yow!

 ml>> i'd love to DIY one of these... if nothing else, it'd give me 
 ml>> something easy enough to do and market and keep me busy... i've 
 ml>> run out of ideas and the job market isn't giving me any hits, 
 ml>> either ;-(

 RJT> You in the market too?  I got "terminated" last wednesday...
 RJT> :-(

 ml> kinda pretty much... been doing a lot of stuff just nothing steady 
 ml> ;-(  getting tired of hunting down my paycheck from week to week...

I hate that aspect of it.

 ml> the economy is so bad in this area that if you hear about any type
 ml> of job opening, you'd best be there waiting in line like folk do
 ml> for concert tickets...

Where are you,  anyway?

 RJT> I went to an agency today that I'd worked before,  and they cut 
 RJT> me loose on a testing machine,  so I started picking out all this 
 RJT> tech stuff just to see how I would do.  I found it bothersome how 
 RJT> much windoze-centric stuff was in there, particularly questions 
 RJT> about w2k,  and you couldn't skip

 ml> yeah ;-(

 RJT> them but had to guess,  but on some of them I did pretty well.  I 
 RJT> may go back there and play with it again,  at some point.  They 
 RJT> tell me that I can also access the system from elsewhere,  over 
 RJT> the 'net.

 ml> i've got access to stuff like that here, too... and one of the 
 ml> real stingers is that people don't think that i'm looking because 
 ml> i don't always leave the house or make phone calls... there have 
 ml> been numerous loud discussions about that and total refusal on 
 ml> their part to even come in and look at the evidence ;-(

Been there and done that one.

 RJT> But anyway,  this is a project that I've been thinking about for 
 RJT> quite some time now.  Years at least.  I don't expect to make 
 RJT> much progress in terms of actually doing anything with it while 
 RJT> we're still stuck here in this little apartment, but that's no 
 RJT> reason why we couldn't kick it around some, either here or in 
 RJT> some other channel,  as appropriate. Maybe ELECTRONICS for 
 RJT> designing some of the driver circuitry,  etc.

 ml> i hear that >

 RJT> Need some stepper motors?  I have a whole box full...  :-)

 RJT> Best ones,  for sheer size,  come out of old *big* printers 
 RJT> (daisywheel,  etc.) and 5.25" floppy drives.  I saw a regular 
 RJT> milling machine one time that had some the size of soup cans...   
 RJT> :-)

 ml> there are times that i've wished i'd kept much of the stuff i've 
 ml> tossed...

I'm at the beginning stages of that process.  Been paying to store stuff
for way too long,  and with little productive coming out of it.

 ml> i've been slowly weeding thru things, cleaning out the place... 
 ml> couldn't even walk thru the house without running into something 
 ml> or having to turn sideways to get thru...

That accurately describes both the hallway and this office,  though the
office isn't as bad as the hallway.  At the very least I've gotta shift
some of this stuff over to storage.

 ml> i can see most of the ceiling, now... 

Well,  that's certainly worse than *I* ever got!  :-)

 ml> and several boxes of stuff to take to the recycler's place... 
 ml> geez, i could have a pretty decent handyman's yardsale if there 
 ml> were a real call for old electronics parts and such...

It finally hit me a while back that I've probably got more parts than I'll
ever use.  Really.  Lots and lots of Rs and Cs and transistors and diodes
and chips and all sorts of other stuff.  And way too much equipment that I
either might get around to fixing at some point (3 monitors in the room
here!) or might end up scrapping out at some point (storage).

 ml> too bad its against the neighborhood charter to have a yardsale

I wouldn't pick a neighborhood like that.

 ml> and i'm not toting it all to the truck to move to some place where 
 ml> i have to rent a booth and such...

A hamefest might work.

 ml> i do know that i've carried over 1500 pounds of stuff out... the 
 ml> recycler has to weight the truck going in and coming out...

Heh.  If I were getting into that much weight I'd load my truck up and go
down to the place that buys scrap metal.  Which might just barely pay for
the gas it takes to get there and back.    If my truck were
showing a current inspection sticker...

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