Ross-O & Reed Irion's CNC Brainstorming Page
--- a place to put research and interesting ideas while I sort all this out ---
----- STEPPER THEORY
(1) Look at the pictures on this site to see how steppers work from an
electromechanical standpoint. Read the other stuff for a good high level overview
(2) Read the theory section on this page. I like this guy - he must have
a graduate degree because in grad school you are taught "copying from one
person is called plagerism, copying from 10 people is called research!" He
does a great job of "distilling" the info found in link #3.
(3) Allegro Micro seems to have the most advanced chips on the market for
stepper control. Their papers give you a lot of insight into the advanced
thoughts and concerns of a stepper motor driver design engineer.
(4) Now for the Grand Finale. Jones on Steper Motors! This is an
excellent online book on the topic. If you were to only read one link - this one should be it!
----- STEPPER MOTOR DRIVER KITS -----
(1) Stepperworld's FET3 looks pretty cool. I think the uses the Allegro
chips but I can't tell - http://www.stepperworld.com/ , click FET3
(2) Camtronics. This is the guy who wrote the excellent Nuts-n-Volts
article on making a home CNC mill.
----- SERVO MOTOR DRIVER -----
--- SOFTWARE --- (see
references at bottom)
Flashcut: "A great Windows based controller that is a bit pricey in today's
market. It was the only game in town for Windows that was affordable. It has
much better constant contouring than the others had until just recently." [Ref 1]
Ahha Artisian: "A great controller that runs in DOS but has absolutely crappy
constant contouring. More starts and stops in arcs than rush hour traffic.
Now, I have the 4.0 version of the software sitting here to test so I don't
know if it helps that one lacking feature or not. It's the only game in town
I know of for change gearless threading on a lathe with an encoder on the
lathe spindle. That's the only reason I keep using Ahha on one machine. ISA
card which can be a problem with modern computers that are dropping ISA
cards." [Ref 1]
Ahha Pro: "( http://www.ahha.com ) Not worth the extra cost of Ahha over some
boardless controls. This card is only the copy protection device. Artisian
at least puts the step timing out on the hardware board as well as uses it
for copy protection." [Ref 1]
Supercam: "Only MaxNC is worse. Dos based." [Ref 1]
MaxNC: "The worst CNC control I've ever seen. Dos based." [Ref 1]
DeskNC: "( www.deskam.com ) Windows and Dos: Works ok. I've never warmed up
to it. I know others that love it. It's makes good parts. They now have a
hardware external option like Flashcut at a much lower cost." [Ref 1]
Probably the easiest and cheapest (as it's free) program to generate G-code
for engraving text with a CNC mill, would be Desk Engrave...
Select any Windows True Type Font, specify X-Y location, Z depth of cut,
orientation (vertical, horizontal, on an arc), text height, type in the text
required and click "generate code". [Ref 2]
EMC: "(http://www.linuxcnc.org/) A fantastic FREE controller paid for by your Federal tax dollars. But,
unless you are a Linux geek, it's a real pain to get installed. Until now.
Get the BDI CD and it's painless. ( brain dead install ) Linux based with
the Linux real time kernel. Supports probing, servo drives and steppers." [Ref 1]
Kelly Cam: " www.kellyware.com Windows based. It's got a LOT of cool
features like Gerber isolation, DXF, Excellon and HPGL import. The motion
however is not smooth. It's written in Visual Basic. I bought it just for
the Gerber and Excellon import. It's well worth it for just that." [Ref 1]
Buckhannon Microsystems: "Last time I looked at it, ( 2 years ago ) it was
almost worthless. No backlash compensation which in my opinion is stupid for
a CNC control.May be OK now but was way over priced. I haven't looked at their Windows
product." [Ref 1]
CNC Pro: "www.yeagerautomation.com The best Dos based, no extra hardware
required controller I've seen. Works great. Still lacks some compensation
features but is a very solid performer." [Ref 1]
Master5CNC: "http://users.andara.com/~fenerty/master.html Absolutely the
most fantastic CNC control I've ever seen. Proves that it only takes a good
.vxd driver to make Windows a real time CNC control. It's smooth smooth
smooth! Only big limitation is 8192 steps per second max rate. That may be a
problem on super fine microstepping systems." [Ref 1]
($100 registration fee. The latest version of Master5 uses the NIST274 6-axis kernel
for its interpreter. See EMC - Ross 8/11/01)
Appears to be DOS based. You must draw with
DanCAD in order to use DanCAM. Cannot import files (Ross) ???
Bad windows front end. Runs OK.
Requires Dongle. [Ref 1] $275-$350 (Ross 8/13/01)
Ref 1: Usenet Newsgroup
Alt.Machines.CNC post by Larry Edington on 8/3/01, subject
Ref 2: CAD_CAM_EDM_DRO post by Brian Harries 8/13/01
Input from Mike Loftus
What I do is this:
1. Find an image I like and save it to BMP.
2. Import BMP into Autocad and trace it on a layer; delete BMP.
3. Export DXF from Autocad and Import into Eval copy of Bobcad.
4. Create G-code program using the "Machine" option of Bobcad. Cut/paste G-code into Notepad and save.
5. Load G-code file into CNC's PC.
6. Run G-code using CNC Pro.
firstname.lastname@example.org (Gotulff) wrote:
>Can some one give me the pros and cons
>one thing Bobcad have or Vector is the way objects are verified. The verified
>function in vector needs improvment. I am kinda leaning towards vector because
>it seems like they make frequent updates.
>Anyone have any suggestions?
As it turns out, I have both BobCAD and VectorCAD/CAM. Background:
I'm an electrical engineer with 32 years experience in aerospace.
I've been using manual machine tools on a hobby basis for 51 years
(started on my Dads shiny new 9" SB in January 1950 at the age of 8
with supervision) but a CNC machine for maybe 2 months. Thus I'm not
a very sophisticated user of either CNC package yet. My CNC machine
is a 2-1/2 D machine. I haven't done anything but drilling holes and
profiling with it so far. I'm contemplating buying my first ball end
mill. Just learning, so what you will get here is the beginning
There are plusses and minuses to both. To begin with, they are really
quite similar on the surface, with about the same level of
customizability and basic model entry (drawing) capability. A
profound difference is that Vector treats lines as vectors (hence the
name I think). BobCAD doesn't. Aside from that, drawing tools are
about the same, although the script language in Vector may turn out to
be a significant advantage once I learn how to use it.
The good news and the bad news about BobCAD is that its strongest
point is that it has a very intuitive CAM interface. It is less
"headstrong" than Vector, and thus easier to so "something" with
quickly and considerably less frustrating to start with. The BobCAD
CAM portion makes a lot less assumptions about what you want, is a lot
less demanding of the model creation process - and therefore less
likely than Vector to be doing something that appears on the surface
to be totally "strange".
The support from BobCAD is said to be someplace between zero and none
at all. I haven't called them except to register it. Since I bought
it from a dealer that was serviced by a salesman that had left BobCAD,
it took me 4 phone calls to Florida and most of the day of vacation I
had set aside to get familiar with it to get the copy registered. The
copy I have is apparently a few rolling upgrades behind the current
version though it carries the same version number. It has a joke for
a manual. I downloaded the help files from their WEB site which are
improved over the ones that came on my CD. I understand that they now
have a manual for it but I haven't seen it.
The CAD features of BobCAD (and Vector) desperately need the ability
to change snap choices on the fly, (snap to mid point of this line on
one end of the line being drawn and change to coordinates or a
different snap mode on the other end of the line). they both get
around this by having nearly all the snap modes active all the time (a
Vector is a program with a lot of potential. You won't outgrow it as
fast as you would outgrow BobCAD. But you pay for that potential with
a steeper learning curve. If it wasn't for the manual, you would use
the Vector CD for frisbee practice after the first two hours. The
drawing features are just barely adequate, but they are adequate and
with some cleverness you can draw about anything you want to (the same
as can be said for BobCAD).
The fundamental difference is in Vector's treatment of drawing lines
as if they were vectors. This is good news and bad news. The good
news is that once you understand the paradigm you can make it work for
you and create offset paths, and other things to be used by the CAM
portion easier than you can do it in BobCAD. Vector is in 3D full
time. You need to pay attention to how you want to deal with the Z
axis even for a simple profiling job.
This needs to be experienced to be appreciated. I understood it
mentally, but not kinesthetically so to speak until after I tried to
make an auto-approach tool path. I input my starting point at Z=0,
and had the path end up at a point on a line that was at the bottom of
the cutting depth of Z=-1.375. The tool path was created just exactly
as i asked for it to be - in 3D. I saw tool paths that were not
constant radius arcs because Vector was creating the arc in three
dimensions - all well and good except my machine can't cut an arc in
three dimensions! Fred answered by question on his bulletin board, so
I changed the view to be able to see the 3D tool path and the mystery
was solved. Now I am very careful to plan out the "Z" axis management
when I am doing a drawing.
Vector creates a non-offset tool path, at least for me, a whole lot
better and more predictably than BobCAD does. The difficulty with
BobCAD is probably operator disfunction, but Vector doesn't seem to
have the same problem with this operator. <G>
BobCAD has some CAM commands that Vector doesn't have. You can input
a command to move to a point, and BobCAD understands that - a feature.
In Vector if you select a point and tell it to create the CNC file
thinking it will move there, you are in for a surprise. If you select
a point, it drills a hole there instead! That is part of Vectors
apparently "strong will".
You must be very precise about what and how you create the drawing and
tool path - it is less forgiving. You need to change the tool path do
make many changes in the Vector G code file. The "G" code editor in
Vector is pretty arrogant about assuming it knows what you want to do.
If you start editing its "perfect" code, it gets all confused. It
doesn't read what you entered and react as the mill will, it does what
the Vector programmers assumed you would want to do there. If it
wasn't for having a separate G code editor to use for annotating the
file and adding in some things that are needed, I wouldn't be able to
use Vector at all until I was about perfect with it.
However the up side of all this is that I think I have a good chance
to get to the point where Vector does things for me that BobCAD
probably won't do, or at least won't do very easily.
Finally, and possibly most important - Vector has Fred Smith as its
apparently more than full time representative. Fred has a WEB page
where he answers questions from users apparently 24 X 7. I confess I
wonder if the guy ever sleeps. He has gotten a manual created for
Vector, and I confess that when I go to the manual to do something the
first time, it usually works. And, the manual has a larger than
required spiral binding so it lies flat on the table or sits easily in
a book holder to make it easy to use it while you are at the keyboard.
It isn't possible to write a manual that is damn fool proof, but at
least this one will support an earnest effort to learn the SW and its
features. Fred isn't a marketing droid. He has obviously paid his
dues using real machines and has learned the SW backwards and
forwards, inside and out.
Vector is apparently improving their package relatively continuously,
BobCAD has apparently not released a major version upgrade in quite a
long time if I understand the posts on the subject. Both packages
could use some improvement, both are usable to get you started.
BobCAd is less intimidating to do something with, you won't outgrow
Vector any time soon.
Since I got Vector and made the first part with it, I haven't opened
BobCAD except to copy the macro file text out of it.
You pick you pony and take your ride.
In So. Cal.
The FAQ for RCM is: http://w3.uwyo.edu/~metal
Metal Web News at http://www.metalwebnews.com
The "Drop Box" is at http://www.metalworking.com/
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