CNC machining process and parts design

Mon Mar 21 14:54:23 CST 2022

CNC machining is a subtractive manufacturing process that uses rotating computer-controlled cutting tools such as drills, end mills, and turning tools to remove material from a solid block of material to shape a part.

The digital design file instructs the CNC machine how to cut the block (also known as the "workpiece"), and multiple machines can use the same design file at the same time, greatly increasing the speed of the production process.

One of the main considerations in machining plastic parts is the shape of the desired part, which will help determine whether a 3-axis or multi-axis process makes the most sense. 3-axis CNC machining involves moving the tool along the X, Y, or Z axis while the tool or workpiece rotates.

On the other hand, multi-axis processes allow the tool and workpiece to move simultaneously, enabling manufacturers to produce parts with complex geometries faster and more accurately without the need to reposition or rotate the workpiece between operations.

The axial limitations of CNC machining mean that the part design must ensure adequate tool paths. This can make certain designs, such as curved internal channels, extremely difficult or impossible to manufacture - which can lead to extensive modifications to the Design for Manufacturability (DFM) for cost-effective production.

Other features that increase part complexity, such as undercuts or design elements on multiple part faces, may require the workpiece to be rotated one or more times, resulting in higher production costs and longer lead times.

However, since machining is a subtractive process, issues such as insufficient wall thickness, draft angles, and sink marks (often addressed during the design stage of cast or molded plastic parts) are less of a concern, making CNC machining a Good choice. The choice for hard-to-form part designs. The precision of the machining process also enables manufacturers to manufacture plastic parts with extremely tight tolerances.