CNC milling is is a process that can create complex 3D shapes in metal and other materials such as hard plastics. A CNC milling machine is controlled by a computer program generated by a CAM application from a 3D model of your part. Since CNC milling does not require hard tooling such as molds or dies, it is useful for small runs of parts and for prototyping. It is also used for post-machining cast or extruded parts to add features that cannot be molded in or that require higher tolerances.
Before creating molds for your die cast or plastic injection molded parts, ChinaForgeTM can often first make prototypes by CNC milling to allow you to verify your design.
When designing your CNC milled parts abide by the following guidelines:
Avoid long, narrow protrusions or thin sections as they will break under the force of the cutting tool.
Use a radius instead of a sharp angle on inside corners.
Try to make your design to minimize the number of faces that need to be machined, as this will reduce cost and machining time.
Avoid deep, narrow cuts as it may not be possible for the cutting tool to reach the bottom.
Avoid holes with very high aspect ratio. Holes that are longer than 3 times their diameter can be difficult to drill.
Try to use as few different hole sizes as possible to reduce the number of tool changes required when drilling.
If possible use metric sizes for your holes and other features, as American sized tools are not as common in China.