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What is CNC Machining?
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<p>
The term CNC stands for 'computer numerical control', and the <a
href="http://www.ideal-cncmachining.com/machining-service/cnc-machining/"
target="_self">CNC machining</a> definition is that it is a subtractive
manufacturing process that typically employs computerized controls and machine
tools to remove layers of material from a stock piece—known as the blank or
workpiece—and produces a custom-designed part. This process is suitable for a wide
range of materials, including metals, plastics, wood, glass, foam, and composites,
and finds application in a variety of industries, such as large CNC machining,
machining of parts and prototypes for telecommunications, and CNC machining
aerospace parts, which require tighter tolerances than other industries. Note there
is a difference between the CNC machining definition and the CNC machine
definition- one is a process and the other is a machine. A CNC machine (sometimes
incorrectly referred to as a C and C machine) is a programmable machine that is
capable of autonomously performing the operations of CNC machining.
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<p>
Subtractive manufacturing processes, such as CNC machining, are often presented
in contrast to additive manufacturing processes, such as 3D printing, or formative
manufacturing processes, such as liquid injection molding. While subtractive
processes remove layers of material from the workpiece to produce custom shapes and
designs, additive processes assemble layers of material to produce the desired form
and formative processes deform and displace stock material into the desired shape.
The automated nature of CNC machining enables the production of high precision and
high accuracy, simple parts and cost-effectiveness when fulfilling one-off and
medium-volume production runs. However, while CNC machining demonstrates certain
advantages over other manufacturing processes, the degree of complexity and
intricacy attainable for part design and the cost-effectiveness of producing
complex parts is limited.
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<h2>
Overview of CNC Machining Process
</h2>
<p>
Evolving from the numerical control (NC) machining process which utilized
punched tape cards, CNC machining is a manufacturing process which utilizes
computerized controls to operate and manipulate machine and cutting tools to shape
stock material—e.g., metal, plastic, wood, foam, composite, etc.—into custom
parts and designs. While the CNC machining process offers various capabilities and
operations, the fundamental principles of the process remain largely the same
throughout all of them. The basic CNC machining process includes the following
stages:
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<p>
Designing the CAD model
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<p>
Converting the CAD file to a CNC program
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<p>
Preparing the CNC machine
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<p>
Executing the machining operation
</p>
<h3>
CAD Model Design
</h3>
<p>
The CNC machining process begins with the creation of a 2D vector or 3D solid
part CAD design either in-house or by a CAD/CAM design service company. Computer-
aided design (CAD) software allows designers and <a href="http://www.ideal-
cncmachining.com/" target="_self">manufacturers</a> to produce a model or rendering
of their parts and products along with the necessary technical specifications, such
as dimensions and geometries, for producing the part or product.
</p>
<p>
Designs for CNC machined parts are restricted by the capabilities (or
inabilities) of the CNC machine and tooling. For example, most CNC machine tooling
is cylindrical therefore the part geometries possible via the CNC machining process
are limited as the tooling creates curved corner sections. Additionally, the
properties of the material being machined, tooling design, and workholding
capabilities of the machine further restrict the design possibilities, such as the
minimum part thicknesses, maximum part size, and inclusion and complexity of
internal cavities and features.
</p>
<p>
Once the CAD design is completed, the designer exports it to a CNC-compatible
file format, such as STEP or IGES.
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