CAD/CAM BASICS
If you're new to the technology there are a couple ways you might view the process. From the viewpoint of a manual machinist there's the question of "How you get the mill to move through the contours I need?" For that perspective we suggest starting at our
Learning CNC
page. From the viewpoint of a designer there's the question of "How do I get from my idea to a completed part?" For this we need to discuss CAD and CAM.
CAD is Computer Aided Design, it's the modern replacement for a drawing board. CAD software is what you use to describe the geometry of your completed part. Once you become experienced with CAD in a manufacturing environment you'll quickly understand that CAD is also useful for describing geometry of fixtures, clamps, vises, and anything else that might have an intimate relationship to the part while your workpiece.
CAM is Computer Aided Manufacturing. This is the software that you use to describe the process for cutting the part. CAM software allows you to translate a CAD drawing into the machine operating instructions. You will specify what tools to use, how fast and how deep to make each cut, and all the other parameters of the machining process.
The output of a CAM program is a G&M code file. This is a plain text file that describes the machine motion in the language that the machine understands. The formal name for the language is RS-274-D, but most people refer to it as G&M codes.
2D CAM is the generation of XY codes without the ability to reference Z (height). Some routers or plasma cutters can use 2D CAM. Tormach does not sell any software limited to 2D.
2-1/2D CAM software allows the creation of parts with full contours in X and Y at any depth. You can control the Z motion, but you cannot do simultaneous X, Y, and Z motion as would be required for things like mold making. TurboCAD/CAM is a 2-1/2D CAM product. For a graphic example,
click here.
3D CAM software allows simultaneous motion of X, Y, and Z. 3D CAM is required for manufacturing molds and other complex surfaces. SprutCAM is a 3D CAM product. For a graphic example,
click here.
NOTE: The issues noted above refer to CAM, the generation of G&M codes. The implementation of G&M codes on PCNC 1100 mill is not limited in terms of axis motion. It can perform simultaneous actions on X, Y, Z, and A (if you have the 4th axis).
Post Processor
As your describe the machining operations in your CAM program, it stores the information as conceptual operations that are essentially machine independent. While the resulting G & M codes might be displayed, the program is actually recording ideas, like "pocket this area" or "edge mill this contour." This is quite different than recording just the motions like "move X 3 inches." A Post, or Post Processor, is a configuration file used by the CAM program, but specific to a certain CNC machine. It tells the CAM program exactly what G&M codes to use, and how to use them, in order to implement the conceptual machining operations on your specific machine. A CAM program will come with a list of post's for various machines, and usually with instructions for creating a custom Post. provided
There are two reasons a custom Post may be necessary. The first reason is that many machines do not properly implement the RS274D language. The second reason is that the RS274D language allows provisions for extensions. Typically the language extensions are used by a machine tool manufacturer to support specialized functions within a tool changer, stock feeder, pallet system, or some other advanced option, feature or function.
CAD/CAM Comparison
Chart
The "thumbs rating" gives an overall view of the capability of the products. We are, however, aware of the very wide range of application of our machines and this is obviously reflected in the optimum software to use. Your choice will also be influenced by any existing CAD software which you run and the investment in training you wish to make for features that you may not yet need.
We advise you to make use of the time-limited or feature-limited evaluation copies of the software to decide what level of capability you require. Software
products and licenses are not returnable items.
|
Product
|
Rating
(5 thumbs)
|
Comments
|
Support
|
Cost
|
|
Alibre
Xpress
|
3D CAD
|
Limited
Editing
Features.
Good tool
for learning
CAD. |
Online
|
Free
|
|
Alibre
Design
Standard
|
3D CAD
|
Allows
designers to
create 3D
designs and
generate and
detail
associative
2D drawings. |
Online
|
$498.00
|
|
Alibre
Design
Professional
|
3D CAD
|
This is the
most popular
choice for
designers.
It includes
tools that
allow you to
work
conceptually
on models,
and analyze
designs with
FEA.
|
Online
|
$748.00
|
|
Alibre
Design
Expert
|
3D CAD
3D CAM
|
This is the
high end
package that features motion
analyses,
engineering
systems, and
CAM
capabilities. Integrated
CAD and CAM.
CAM is Mill
only.
|
Online
|
$1196.00
|
|
SheetCAM
|
2 ½ D CAM
|
The latest
version is
limited to
150 lines of
generated
code.
|
Email
Online
|
Free
|
|
SheetCAM
License
|
2 ½ D CAM
|
Extends the
program to
unlimited
amount of code lines.
Easy to
learn. Mill
only.
|
Email
Online
|
$178.00
|
|
SprutCAM
2007
|
3D CAM
|
Includes
lathe module
software and
powerful
turning-milling
methods.
Includes
both Mill
and Lathe
CAM.
|
Email
Online
|
$992.00
|
|
TurboCAD
Professional
|
2D , 3D CAD
|
A precision
design
solution
that has
integrated
2D drafting,
3D surface
and solid
modeling,
and 3D
photo realistic
rendering.
|
Online
|
$330.00
|
|
TurboCAD
CAM Plug-In(requires
TurboCAD)
|
2 ½ D CAM
|
The CAM
Plug-in for
TurboCAD
integrates
CAM to your
CAD program.
Includes
both Lathe
and Mill
CAM.
|
Online
|
$165.00
|
