Re: [CAD_CAM_EDM_DRO] Watch finishes, by CNC

Hi Chuck,

Pocketing routines can actually be pretty, I have them on the beam I
machined for my Baby Beam Engine. The beam is tapered at the ends, and
looks somewhat like an I-beam in cross section. Pockets on either side
reduce the cross section thickness. It uses a spiral to do pockets,
courtesy of Vector CAD/CAM. This would leave a minute pattern if you
used a small cutter, but would not give you the "engine finish" I
believe you are describing. To do this, I'd suggest programming a set
of points in the proper order to get the overlaping patterns. A drill
cycle (G81) with depth at the surface, and a little retract would create
the patterns, and the "connect at Z" command would order the moves of
the emery disk between points.

Now it comes to creating a set of points in spiral, concentric circles,
etc. patterns as you require. Perhaps Corral draw could aid here.
Although Vector or another CAD program can generate, rotate and
replicate sets of dots as well.

If you know the mathematical function that will generate points you
want, they can be input in CAD programs. Vector uses PLC to do this
(sorry, not familiar with other CAD program import functions).

HTH

Alan KM6VV


Chuck Knight wrote:

>
> http://mywebpages.comcast.net/timconnor/ham922/ham922_07.jpg
>
> I want to do this type of finishing to a watch movement, just as an
> experiment...isn't it pretty? This style of decoration is done by using
> a rotating emery disc, and a watchmaker's lathe...lots of tedious
> handwork. I'm thinking of attaching an emery disc onto the end of a
> dowel, and chucking it into a router. Needless to say, there is no
> pressure involved, but only light contact and a precise and slightly
> overlapped toolpath. Given a small, reasonably accurate CNC router,
> this should be simple to achieve. FYI: This watch is from the turn of
> the last century -- one with this level of decoration would cost a
> minimum of $2500, and most are closer to $4000, in today's market. This
> one cost >$100, 100 years ago...this is one of the super-accurate
> railroad watches that kept the trains on time.
>
> Back to CNC. As I see it, once I have a tool made, it should simply be
> a matter of programming the toolpath. Does anyone have a program that
> would automatically generate a spiral, concentric circles, straight
> parallel lines (cotes de geneve) and other simple "filler" patterns
> which I could use for this purpose? I don't want to "reinvent the
> wheel" if I don't have to. I already know that the dust generated will
> require me to clean the movement afterwards, but for the purpose of this
> experiment, I'll happily do it. I could probably do it myself, but I've
> never programmed in G-Code.
>
> I know there are simple "pocketing" programs floating around...what
> types of paths do they generate?
>
> -- Chuck Knight
>
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