I Think I CAM, I Think I CAM ...
My favorite piece of CAM software is Vectric’s
VCarve Pro. This is by far the easiest-to-use CAM software
on the planet. I also like how their software shows you a
3D preview of what the finished part will look like
(Figure 2). I mention the CAM software first because the
feature I like best is the built-in drawing tools, as opposed
to other applications that require third-party drawing tools.
This allows you to blend the first and second phases with
a single piece of software.
Given that, we will skip the first phase and blend it in
to the second phase when we get to that point.
This article is not intended to be a step-by-step tutorial,
so I will not go into the details of how to use VCarve Pro.
There are plenty of excellent tutorials and sample projects
on their website if you need help using any of their
software. You can download the design files for this
project at the article link or at www.probotix.com/
downloads to help get you started or if you want to
simply recreate my design.
The first step in the CAM software is to define your
stock (length, width, and height) and also where you want
the origin (the zero location) to be. You can choose the
back right corner at the bottom of the stock, top dead
center, front left corner, or the top of the stock — it’s
wherever you need it to be. It can depend on a lot of
things, but typically people use the front left corner at the
top of the stock.
The next step is to import your drawing from another
drawing program. In this case, you can take advantage of
Vcarve’s built-in drawing tools to create your shapes. I
design machines and electronics for a living, so
mechanical design comes naturally to me. However, I
really struggle with organic design. So, whenever I come
across a project like this, I rely on a variety of resources to
Design, Fonts, and Clipart
There are plenty of sources of clipart available online,
but many of them are click farms in disguise, so beware. I
really like the CD-ROM/DVD clipart collections that include
categorized catalogs (long live print!). Most of these designs
require a lot of cleanup before they can be machined. They
were not designed for CNC and will often have both
disconnected and hidden vectors that have to be reworked
first. Boolean drawing tools are your friend here.
Another great source of simple shapes are themed
dingbat fonts. They require very little work to make them
machinable. The horned head in my design was one of
the “letters” in such a font. Speaking of fonts, there are
tons of free font websites out there where you can find a
multitude of themed type styles for your designs.
Once you are satisfied with your design, you will
assign tool paths to the various shapes in it. Vcarve has a
variety of tool path operations, but for this project we are
only using the pocketing and profiling operations. With
any of the tool path operations, you will be assigning the
tool geometry, starting depth, depth of cut, step-over, feed
rate, plunge rate, direction of cut, and so on. Because I
was working with foam, I was able to take some overly
The order of operations is important when laying out
your tool paths. For instance, you may need to cut your
shallower pockets first when you have overlapping or
embedded pockets. If the stock is being held from the
outer edges, the last operation should be to do your final
82 September 2014
FIGURE 2. 3D view of the
tombstonedesignin VCarve Pro.
CNC: Computer Numerical Control. The automation of machine tools
that are operated by precisely programmed commands encoded on a
storage medium. Mechanical automation by use of computer
CAM Software: The software that creates the tool paths for a CNC
machine. It takes a 3D model or a 2D drawing as input and allows the
user to choose machining operations for the various features of the
model or drawing. The primary function of the CAM software is to
calculate the tool paths by offsetting half the diameter of the tool from
the final requested shape. The CAM software outputs the g-code
required to run a CNC machine.
Vectors: Images defined by geometric shapes, points, lines, and
curves, as opposed to bitmaps which are decribed by colors on a grid
Boolean: Boolean operations on polygons are a set of Boolean
operations (AND, OR, NOT, XOR ...) operating on one or more sets of
polygons in computer graphics. These sets of operations are widely
used in computer graphics, CAD, and in EDA (integrated circuit physical
design and verification software).
Pocketing: Machine toolpath that plunges or spirals in and out of a
pocket to cut a space such as those around a letter.
Profiling: Tooling operations that follow the outline of a shape.
Die Grinder: Pneumatic power tool for grinding, sanding, and