Re: software questions

--- In CAD_CAM_EDM_DRO@y..., "stevenson_engineers" <machines@n...>
wrote:

> --- In CAD_CAM_EDM_DRO@y..., "starcast82" <rh@g...> wrote:
> > I'm new at this so bear with me. From my understanding of CNC
> > software, If I use AutoCad I am basically drawing the toolpath of
> >the
> > cnc and not the object itself ? Is there a program where you draw
> >the
> > object and then the computer plots all the paths and does all the
> > calculations determined by cutting width of your tool(Is this

what

> >a
> > CAM program is) ? Is there a difference between a CAD program and

a

> > CAM program ? I currently have Autocad and TurboCNC and trying to
> > decide how it fits together and if there is other recommended
> > software to use or if I need a CAM program also. Thanks for the
> >help.
>
> Most CAM programs require that you draw the tool offset path as you
> have found out. The only low end program that I know that doesn't
> require this is Dolphin.
> Dolphin automatically adds on or subtracts half the width of the
> cutter to generate it's own toolpath. All you see on the screen is
> the object itself.
> To generate a CNC cut part you need three elements. A CAD program

to

> draw the part. A CAM program to generate the code for the toolpath
> and a controller program that moves the motors.
> There are combined CAD/CAM packages out there like Bobcad, Vector

and

> Dolphin. Bobcad and Vector are integrated programs where the CAM

side

> is closely built into the CAD, ie writing code as you go.
> Dolphin is two seperate modules where the code is only written when
> all the job is done to your satisfaction.
> In fact in Dolphin it's possible to bring a DXF file in from say
> Autocad straight into the CAM side and miss out the CAD side
> completly.
> Dolphins web site is at http://www.dolphin.gb.com
> Well worth a look.
>
> John S.

Some excellent points John, I would just like to add to it by saying
that the Dolphin system also has the option on most milling routines
of leaving a finish allowance in X/Y and/or Z.
So roughing and finishing routines for pockets are made very easy. By
using an area clear with a finish allowance, followed by a go-round
routine to do the finish pass, you have the option of allowing the
Cam system to work out all of the offset toolpaths (as John pointed
out, you don't have to draw any toolpaths in Dolphin), and you can
also output the actual component dimensions (part surface)on the go-
round (finish cut) routine, and use your controls cutter compensation
routine. This is required if you have a tight tolerance to maintain,
or if you are using odd sized/reground cutters.
In Dolphin you can output either (via post processor) a compensation
command (G41/G42) for the compensated toolpath, which allows you to
enter a 'wear factor' into your CNC control instead of the actual
cutter size, or, you can output the component size and enter the
actual cutter size into the tool library.
I personally would always use the latter, that way you avoid any
silly errors caused by forgetting what value you are supposed to be
entering into the tool library, after all, a box that says 'Tool
Radius' should have the 'Tool Radius' entered into it. Keep it simple!

Dave Pearson