Re: Watch finishes, by CNC

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Chuck Knight
<chuckknight@h...> 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.

> 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?

Chuck, these kinds of processes can be made fairly easily with Vector
CadCam. The spiral is done by creating a series of points and
interpolating them into a nurbs curve. The curve can be then
converted directly into G-code, with or without arc fitting.

The points may be directly created using the Vector copy-paste
function, with multiple copies and rotations settings, so you only do
it one time. You can also use the free Macro Tool Bar to create
points using mathmatic equations. Again a Nurbs curve is created
using the Cad points. If you use Macro Tool Bar, you can experiment
with many different formula to make a variety of patterns. Look
through the CCED archives for some Spirograph type formulas in the
links.

Other things that I do to make decorative patterns:

1) Hatching and cross hatching can be used to create tool paths in
Vector. Vary the angle and distance between the lines to create
various patterns, including a knurl appearing one if you use a V-
tipped angle cutter on a cross hatch.

2) The Clean Circle function will create end to end tangential arcs
that look something like a spiral.

3) Any image or clip art can be traced and the basic pattern can be
tiled (arrayed) to produce a decorative image either for engraving or
for pattern repetition with abrasive cutting methods.

4) In the Vector XT CAM manual there are a few Macro Tool Bar Pro
scripts that can be used for Trochoidal milling. Trochoidal milling
is one of the latest buzzwords in machining. It is a cutting process
that varies the depth of side cut to kind of simulate the process you
would use to manually machine. You crank hard and back off when the
chip gets too dark, crank hard again and repeat. This is controlled
very precisely to improve metal removal rates, especially when
cutting without coolant. The tool path looks like a series of
overlapping spirals, which vary the depth of cut along a line or
curve. The same toolpaths can create a swirled/brush look.

Fred Smith - IMService
We are THE source for low cost Cad Cam
Group discounts and specials are at:
http://www.imsrv.com/hobby