CNC Machining Parts with Geometric Complexity: What Are The Design Restrictions?

Design Considerations for CNC Machining of Complex Parts

While CNC machining offers remarkable design flexibility, it is essential to recognize that not all geometries can be readily manufactured using turning and milling machines.

Unlike 3D printing, where complexity does not necessarily equate to increased costs, CNC machining follows a different paradigm.

In this context, the greater the design complexity, the higher the machining costs due to the additional steps involved.

The primary constraints associated with CNC machining revolve around the geometry of each specific cutting tool.

The tool's geometry determines the radii of a part, and most CNC cutting tools exhibit cylindrical shapes with limited cutting lengths.

Consequently, achieving sharp internal corners poses a significant challenge.

Tool access represents another pivotal limitation in CNC machining.

For instance, 3-axis systems are constrained in terms of part complexity since all features must be accessible directly from above.

In contrast, 5-axis systems offer superior flexibility by allowing adjustments in the angle between the part and the tool, enabling access to otherwise challenging areas on the workpiece.

Moreover, CNC machines encounter difficulties when handling parts with thin walls or delicate features. Thin walls are susceptible to vibrations and may fracture under the forces exerted during turning or milling.

As a guideline, it is advisable to design metal parts with a minimum wall thickness of 0.8 mm and plastic parts with a wall thickness of 1.5 mm.

Comprehending the degree of complexity feasible for various machine types and being aware of these constraints is crucial to ensuring that your designed parts are successfully produced to meet your desired quality standards.