Re:Re: RE: Thoughts on Gcode interpreters and CNC controls....

--- In CAD_CAM_EDM_DRO@egroups.com, ballendo@y... wrote:

> dave wrote:(below),
>
> Isn't this what Fred Smith's new program does, or can do??
> Fred?
>
> Ballendo
>
>
>
> >No practical experience yet since my emc, etc is not running:
> >Because of the kind of things I do.....replicate parts made 150
> >yrs. ago....I tend to think in term of the ops that a horizontal
> >mill does: which leads to a object (entity) library: inside and
> >outside hemi-cylinders, holes, pockets, etc. with parameters to
> >define x, y, z, centerline, tilt, etc. as needed. Now all I need is
> >the solid geometry package that supports this. :-)

This would be called a parametric Feature Based Cam. Our new software can easily duplicate a surface from a scan, using a Ball mill for example, but "edge" work is still best done with a flat endmill or face mill or drill.

Vector is probably more capable of this, in that it can import geometry from external sources like a spreadsheet or data base. This would be contrasted say to having the parametric definitions as part of the control, say with TCL and EMC. I like to do it in Vector, because the output can be visually verified & I have developed a great confidence in Vector's ability to deliver what I see on the screen to the cutting zone between a part and an endmill.

We have a user programmable DDE(Dynamic Data Exchange) server in beta testing right now that allows one to program just about any set of product families and feature sets, externally, but the geometry and code "auto-magically" appear in Vector after clicking OK on a parametric dialogue.

Very similar to a VBA interface, except that it is not limited to VBA, but will also work with VB, C, Powerbasic, or any other language that is DDE capable. Hey Ray is there a DDE hook for TCL?

Vector users already have a DDE application in their installations, called Gear.exe. Running the program with an open Vector document, generates the complete gear geometry after entering the values for a metric Module gear.

This concept can be easily extended to a complete product line. One of our woodworking customers is implementing a window treatment product line of 10 items that have variable dimensions. Their application started out as a PLC, simple generation of raw geometry & import into Vector. Now it is nearly completed and the interface steps are gone, as clicking the OK button places the calculated geometry in Vector, but instead of having to calculate all the numbers, the program actually uses Vector's functionality to build the geometry.

To generate the code for a rectangle(with offset curve, approach-depart & Z connection) the actual DDE commands would look like this(missing numeric parameters for coordinates):

Draw line
Draw line parallel
Reverse last
Closed shape mode
Draw line connect
Fillet all

Offset curve
Approach
Insert nc
Generate nc.

Note: This is actually much shorter if the rectangle function is used(eliminate the first 6 lines). ;-) Nearly all of the complex functions in Vector are DDE encoded, as are most of the menu items. To pocket the rectangle would just be a matter of adding one more line with parameters and removing the offset curve and approach lines.

The programming is quite simplistic for a Vector user, and will only require a code wrapper that allows execution of the above in a script manner. It is a very simple exercise to develop this style of scripts to generate a lot of geometry.

Between this and the simplified surfacing capability of StlWork, big chunks of the time to develop CNC programs- precise cad drawings will be much more productive, surfacing from direct scans or solid cad models. Especially as we will eventually have at least a rudimentary library of basic shapes and feature scripts or else actual compiled programs.

The gotcha here that a parametric Cad program gets the edge is that the geometry once created can be changed later and features of a given shape or series of shapes can be parametrically related so that they all change if a single given dimension or detail is changed. In Vector at least in the present form, the feature data can be stored as layer identification data only. In theory the DDE would allow one to parse and reverse the features for modification, but it's not too pretty.(the word Kludge comes to mind) Hopefully within the next version or so some of the present database constraints will be lifted and we may even have some unused data elements or types that could be allocated to direct feature definition and variable parameter. All of Vector's entities can be modified parametrically, but they cannot have an algebraic relationship between others.

We have looked very closely at a couple of these programs, but so far they are all over $3500 retail and the best deal that we have stumbled on so far is a $1500 prospect(retail). Still quite high for home/hobby use. (at least for me)

PS. I put up some new pictures that show how to use StlTrans to convert a black & white raster clipart image to a 3D solid surface and carve it out with StlWork. Say hi to George.

Fred Smith
IMService

StlWork is at http://www.stlwork.com