Hardware Reference
In-Depth Information
Milling and Cutting
Other fabrication processes work by cutting or removing pieces of a larger stock material.
Laser cutters cut 2D shapes out of plywood, cardboard, acrylic, and other flat materials.
Vinyl cutters do the same, but with a knife that cuts through thin materials like paper
or adhesive-backed vinyl. The water-jet cutter handles stronger and thicker materials like
wood, metal, and glass, cutting with a stream of hard particles in a powerful jet of water.
CNC (computer-numeric control) machines, like mills or routers, work in three (or more)
dimensions, removing material from solid blocks of stock with a variety of cutting bits.
They are often capable of very precise operations, albeit only within specific axes of move-
ment. Compared with 3D printers, these cutting and milling tools have the advantage of
being able to work with a variety of existing materials, including natural ones with com-
plex structures that are difficult or impossible to replicate with the homogenous stock of
most 3D printers. They are more limited in the geometries they can produce, however, and
often require more steps in fabricating or assembling the parts.
In addition to specifying the geometry of the design itself, it's important to be explicit
about the nature of the stock material and the characteristics of the cutting process.
Whether two parts press-fit tightly together, slip past each other, or don't fit at all depends
as much on the precise thickness of the stock (which can vary even across nominally equi-
valent materials) and the thickness of the cut as on the shape in the file. Some construc-
tions may be infeasible to achieve given the tolerances of a particular machine. (Laser cut-
ters may yield slightly different cut thicknesses on different sides of their working area;
water-jet cutters can give rough, nonvertical edges, for example.) Traditional engineering
drawings often capture the required tolerances for various surfaces and the material to be
used. A quickly created CAD file used for a prototype and then thrown up on a webpage
may not. Parts might be sanded, glued, pounded together, or otherwise tweaked in ways
not reflected in the design files. Generating tool paths for a CNC machine is a complex
process with a significant impact on the form and finish of the resulting object; this com-
plexity may not be possible to capture in a way that can be easily shared with others, par-
ticularly if they are using a different machine. Finishing and assembling parts created with
CNC devices requires careful craft, which might be difficult to communicate or learn. All
of these factors need to be kept in mind when designing or sharing a digital file for
someone else to replicate.
