Re: Beginning User

--- In CAD_CAM_EDM_DRO@y..., "Carol & Jerry Jankura"
<jerry.jankura@s...> wrote in the post below my reply:


Good post by Jerry, well explained.
In addition to looking at Vector you may want to take a look at
Dolphin.
http://www.dolphin.gb.com
This can do the same but it does it automatically. If you draw your
inch square and tell the program you have a 1/4" cutter it will work
the offset out automatically so you still have an uncluttered
drawing, just the square. It can also add on enough for a finishing
path. This finish path also has the option of being cut at full depth
to give a blend free finish.
Change the cutter and the program updates, no need to redraw the
offsets.

John S.

> Hi, Eric:
>
> I haven't heard of a "CNC jr" (I'm not too experienced in this field
> either), so could you explain exactly what you got?
>
> Most of the hobby CNC G-Code interpreters do not provide cutter
>compensation
> (G40->G42), so I'm not surprised that your's doesn't either.
>
> A couple of suggestions -
>
> 1. Since autocad lite will generate a DXF file, you might want to

consider

> drawing an offset to your cutting lines equal to the radius of the

cutter.

> Let's say that you want to cut the outside edges of a one inch

square using

> a 1/4 inch diameter end mill. You'd draw the square using autocad

lite and

> then draw an offset 1/8 inch away from each of the lines. At the

corners,

> you'd draw a 90 degree ard with the corner of the square being the

center of

> the arc, and the radius being 1/8 inch. You would draw all of these

offsets

> on a separate layer (let's call it 'toolpaths') Export this drawing

as a DXF

> file.
>
> Next, download a DXF to G-Code interpreter such as ACE Converter

from Yeager

> Automation. Open the DXF file that you just generated with ACE,

select the

> toolpaths layer, and direct ACE to generate the G-Code. Now,

manually edit

> the G-Code file that was just generated to add carriage feed rates,

depth,

> etc. If you're trying to cut a 1/2 inch deep cut, you'll want to

copy and

> paste the code that Yeager generates several times, changing the

depth of

> cut for each iteration (You don't want to cut the full 1/2 depth at

once,

> Depending on material you're cutting, you'll want to make a series

of cuts

> along the same path, but at different depths until you reach the

full depth

> of the cut. You may also want to cut a little "outside" of the

lines as you

> remove most of the material, and then take a full cut finishing cut

that

> removes little material, but provides a clean, uniform surface, but

that's

> another story)
>
> This is your "low cost" solution. And, if you prefer a CAD program

that

> offers a little more power than ACLT, you might want to download a

free

> version of Intellicad, an Autocad workalike. Your net software cost

is

> zilch.
>
> 2. Since you're willing to spend some money on a program, you might

want to

> consider one of the CAD-GCode interprepeter generators such as

VectorCADCAM.

> The advantages of programs like Vector are that they often

provide 'helps'

> to the G-Code generation process. For example, the cut that I

mentioned

> before could have most of itsG-Code generated by drawing the offset

(which

> would also draw the radii around the corners) and clicking on a

button.

> You'd then enter the depth of cut in a dialog box, and Vector would

generate

> all of the iterations necessary to cut to full depth. Then, you'd

add

> another cut to finish it off (this may be automatable as well, Fred

might

> comment here) Since you know the autocad type programs, moving to

something

> like Vector would have an unlearning curve as well as a learning

curve (I

> started with the Intellicad-ACE combination and have moved over to

Vector,

> so I've gone through this curve), but it's well worth it, IMHO.
>
> Now, as far as your G-Code interpreter is concerned. If your motors

use a

> step-direction interface with the computer, you can replace the G-

Code

> interpreter with one of several. Most are low cost ($20 -> $200)

and run

> under plain old DOS. A few run under Windows 9x. There's a WinXP

beta out

> for one. If you're willing to move to a Linux environment, there's

EMC (I

> was not willing to move to this environment, so I can't comment on

its

> capabilities)
>
> In any event, I hope these comments provide some help and

direction. You'll

> find lots of folks more knowledgeable than me who are also willing

to share

> their experiences and insights.
>
> -- Carol & Jerry Jankura
> Strongsville, Ohio
> So many toys, so little time....
>
>
> |-----Original Message-----
> |From: exeric1 [mailto:exeric1@y...]
> |Sent: Friday, July 05, 2002 10:42 PM
> |To: CAD_CAM_EDM_DRO@y...
> |Subject: [CAD_CAM_EDM_DRO] Beginning User
> |
> |
> |Recently I purchased a CNC jr. I'm very happy with it for the most
> |part but there doesn't seem to be very much native G code for it.
> |There's no G code for tool diameter (radius) offset for example. It
> |looks like I'll have to get a cam program sooner rather than

later. I

> |will be using AutoCad Lt for the design portion. I'm interested in
> |suggestions for a cam program that will work well with such a
> |restricted native G code. I don't need any design features in the

cam

> |program since I've already got CAD. Any info would be greatly
> |appreciated. I really would rather not pay more than 600 or 700
> |dollars.
> |
> |Another question I have is about using cutting fluids with CNC. The
> |system I have that came as an option with the CNC jr seems like it
> |puts out too much - It makes a mess of everything. Are there any

good

> |ways out there to manually control the flow. Also I would like to

use

> |a vacuum system for the metal chips that I already have set up for
> |woodworking. What's a good method to get the chips without sucking

up

> |the cutting fluid? I've got a recirculating system for the cutting
> |fluid and its too expensive to just get sucked away. Thanks in

advance

> |
> |Eric
> |
> |
> |
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