Re: Art dxf file is suitable for working on sheetcam or not

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Dick Douglas

Re: Art dxf file is suitable for working on sheetcam or not

Post by Dick Douglas » Thu May 28, 2009 10:58 pm

Good morning Mongkol

You say that you are decreasing the number of nodes in your drawing? My
theory is that to make a curve smoother you break it up into smaller
segments or more nodes. It also appears to me that SheetCam tries to
convert apparent curves (lots of segments) to the appropriate g02/g03
code. When exporting your design from CorelDraw you have the option of
picking one of 54 formats to convert the Corel design. svg is one of
your choices.

When importing svg file into SheetCam (TNG versions) file>import drawing
= 'open a drawing' dialog, you have four choices for file types: svg,
hpgl, exellon and dxf. In trying to understand why you don't see svg as
an option, I went back to the "old" version of SheetCam 6.2.0 and found
that Les has replaced the Enhanced Metafile format with svg for TNG
(thanks Les). You need to download the TNG version (yesterday Les
upgraded to ver 1.1.13).

Until I played with SheetCam's import options, I hadn't heard of or used
svg files myself. After playing with all the available SheetCam options,
dxf and svg seem to work the best options when exporting from CorelDraw.
I searched online using the keyword svg to learn about the format. I
think it was an Adobe idea and now there are many people working on or
with svg. I found a little program called Inkscape that seems to have
svg as its native file format. It appears to be very capable. Haven't
had time to play with it. hummm, I do have a little part I need to cut.
I might try Inkscape to design the part, then output a svg file as well
as a dxf. Then draw the part in CorelDraw. Then take all the files
through SheetCam and compare the differences in the resulting g-code
listings. Whew. I need another holiday just for playing and testing.

The reason I am beginning to like svg files is that I seem to be getting
better results than dxf for the curves when I cut.

I have not compared PlasmaCam output with what am getting from SheetCam
+ Dynatorch. PlasmaCam did seem to do a good job of taking Corel's dxf
files. It has been over a year since I used the PlasmaCam. I seem to
remember having to fine tune some of the designs. PlasmaCam was my first
plasma CNC experience. I would love to have the PlamsCam and DynaTorch
side by side to compare ease of use.

I am still confused about your use of "Art file." Are you talking about
files that are made from the "art" designed in CorelDraw?

DynaTorch. When I first looked at a DynaTorch machine, I was impressed
that it had a much sturdier frame than PlasmaCam. I also liked the 5' x
10' table compared to the 4' x 4' PlasmaCam. The DynaTorch also uses the
machine torch. PlasmaCam uses the hand torch. The hand torch setup was a
constant irritation. Both machines have the HyperTherm Powermax 1000.
Now, PlasmaCam seemed to handle the 3/4" plate we put on it. We always
seemed to hold our breath as we gently set it down. But the plate didn't
collapse the table. PlasmaCam uses stepper motors. The DynaTorch uses
Animatics SmartMotors servos and what appears to be their own
controller. I would imagine it would be possible to run the system with
Mach 3. Our system came with DynaTorch's software. I have never found
the need or desire to try Mach 3. A little plus with DynaTorch is the
ability to plug in a game controller or joystick to control the table.
Don't use it a whole lot. But it is nice to have a "remote" to move the
torch and cut sometimes.

DynaTorch also has a dxf conversion module. I found it to be rather
primitive. At least that was my first impression after the seamless
manner of moving a CorelDraw dxf file into the PlasmaCam. The first
thing I noticed was the lack of a lead in/lead out function. I then
started searching and found SheetCam. Then I discovered that DynaTorch
had SheetCam as an optional software package. SheetCam offers greater
flexibility than PlasmaCam's built in function.

Lastly. You mentioned candcnc's THC. DynaTorch's software has the torch
height control built in. DynaTorch's THC works extremely well with the
HyperTherm. If I remember, the THC never really worked on the PlasmaCam
and the PlasmaCam folk never supplied the answer or fix. One plus or
maybe a negative with DynaTorch's software is the multitude of settings
that are available to the user. The plus is that once we learned how to
fine tune everything to our situation we can cut exactly the way we
want. The negative is that we had to learn how to use all the settings.
But DynaTorch's people are always helpful in solving a problem or
answering questions.

Did I answers all your questions?


mongkolnum wrote:

I import art-dxf file to coreldrawX4 and improve it with dxftool.
I try using demo dxftool before thinking to order.I try solving on
curveline with bezier tool by handtrace.It can decrease multinode
on curve but it is not good on sheetcam after convert with dxftool.
Good idea with dxftool for some nodes.
Could you advise me for your experience? I have some questions.
1)You tell me that you save artfile with SVG file and sheetcam can
handle it smoothly. I am little puzzled that I don't see sheetcam
can import SVG file.It only imports dxf,HPGL and so on,not SVG file.
I have not ever heard with SVG file. How to import to sheetcam?
Pls advise me for the website of SVG if it's possible.How to order?
Curve on SVG file is OK or not on sheetcam?
2)Have you ever used plasmacam software to compare with sheetcam?
Which software is better than for artfile? I think sheetcam is low
cost and good jobs for plasma machine,For Art file, I don't know how
to handle.
3)Dynatorch,It's very famous with plasma cnc machine.Sounds like it's
compatible with mach3,sheetcam and candcnc's THC. Is it correct?

Thank you for your experiences

--- In <>,
Dick Douglas <dick@...> wrote:

not sure what you mean by "art-dxf" file. not sure if you used
from the start or not.

if you used coreldraw to design, i can tell you of my experiences. we
use coreldraw exclusively to design. we now use a dynatorch to cut our
metal. before that we used a plasmacam. the dynatorch is a much
sturdier machine. we also enjoy the 5 foot x 10 foot table compared to
plasmacam's 4 foot x 4 foot size.

i did find plasmacam's software to be much more coreldraw friendly. it
was a simple process to import corel's dxf files. dynatorch has a
steeper learning curve, but once we got a handle on all the parameters
and settings dynatorch performs incredibly well.

we were extremely happy when we found sheetcam. it makes getting our
files to cutting metal almost a dream. and les has been super about
solving problems and keeping us updated as he improves the program.

now as to your curve problem from coreldraw. as les and other will
explain, corel exports curves as spline segments, not true curves.
dxftool for coreldraw does a better job than corel on curves. not 100
percent, but better. it is fast and a good tool. however, we found the
interface a little clunky. so clunky that we decided to wait until it
was improved before we use it on a regular basis.

one way we were able to improve dxf exports was to use corel's add node
function. we are currently using version x3 (since version 9 we have
found the odd numbered versions the better investment). if you chose an
entire object corel will double the nodes on the entire object. if you
select some nodes the add nodes function will add nodes between and
around the selected nodes. sheetcam takes a little longer to process
additional nodes and the resulting g-code has a lot more lines. with
fast computers today, we find that generally the processing time is not
all that great.

lately we have been exporting our designs from coreldraw as svg files.
sheetcam seems to handle them very well. we haven't seen any problems
yet. svg files move to sheetcam then to dynatorch in a very smooth
these thoughts are primarily for using coreldraw. i am not sure why you
are having strange noises or wavy curves. answers to those are
beyond my
experience. les and the other sheetcamers might know the answer.

good luck


mongkolnum wrote:

Les and Experter,

I need your help. I loaded art- dxf file to sheetcam. If I zoom in ,I
will see the curve is not smooth.( it composes with multiline). I
converted it to G-code and run with my plasma cnc machine. I found
motorX and Y move abnormally while cut sheetmetal on curve ( sounds
like it have a spasm).-->After cutting, I found the edge of metal
is not
smooth on curve ( looks like wave),not beautiful . I tried to
solve the
problem of curve with corel draw & dxftool to decrease multinode but
the edge of sheetmetal is not OK.

My questions

1) Sheetcam is suitable for working on art-complicated file or not.

2) Is it possible to solve the problem of curve or arc on sheetcam ?
---> If the curve is smooth,G-code is OK also.

remark: I use sheetcam version 6.2.0

.( If I cut rectangular,circle,geometry or cad file,the edge of
metal is
smooth and OK after cutting.)

Hope your help



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