Re: Newbie CAD CAM question!

--- In CAD_CAM_EDM_DRO@y..., "lathelathe1" <sme@p...> wrote:

> Hello Group,
>
> I am a little confused!
>

Hopefully after the other posts you are less confused. In a perfect
world you would have one program that does everything but we are far
from perfection.

The first step is to draw what you want to make to scale. Your
choice here will determine what happens next. If you draw in 2D then
there will be no "Z" information in the file. DXF is short
for "Drawing eXchange Format" and is a way for programs to move
vector type drawings around. The Autocad native format is DWG but
not all non-Autocad programs read that file type. If you want to cut
anything but lines you need to have closed "objects" inside your
drawing. A closed object is a series of lines/splines that start and
end in the same place (Circle, squares, polygons, etc)

Let,s assume you have drawn your part in 2D CAD and exported it in
DXF format. The next step is the CAM program that lets you refine
the drawing and add things like depths and alter the order of the
objects. Some more advanced CAM programs will display a 3D screen
simulation of the part. Also in the CAM program you will define the
cutting tools, offsets, number of passes, etc. You can select a
closed object then assign a depth and tool. At then end of all this
the CAM program should spit out a gcode file based on what is called
a post processor (there are variations of gcode dialect). Gcode is
lines of text that are fairly easy to read and edit.

With your Gcode in hand you then need a program that takes something
like G0 X2.135 Y3.550 F15 and translates how many steps it takes on
YOUR machine to move the X axis to 2.135 and Y axis to 3.550 at a
feed rate of 15IPM. That program is the Controller and should take
gcode from just about any source and turn it into machine moves.

Now for the confusing part. Several programs combine all or some of
the aspects of the three distinct types. Most often it is the CAD
and CAM pieces.

In it's simplest form you can (if you are so inclined) sit down and
write the gcode for every move in a word processor or spreadsheet and
deliver that to a Controller. In certain circumstances that might be
the fastest way to cut a part. Using that method you can make parts
with just a text editor and the Controller software.

After reading this it may sound overly complex, but once you have the
pieces setup and learn how to move from one to another then it really
is quite simple. There are many other aspects but I have tried to
keep it to the basics.

IMHO the CAM software (unless you are doing 3D design and modeling)
is the most important piece and is the hardest to learn. Be prepared
to make an investment in time regardless of how much you pay for the
software. You will have to make this investment each time you change
programs because no two are alike.