Surface Finishes

As Machined Services

All your designs are secure and confidential

As Machined

As machined refers to the quality and texture of the surface of a workpiece immediately after it has been machined by a CNC machine. It describes the appearance and smoothness of the material’s surface resulting from the cutting, milling, or other machining processes. Surface finish as machined is typically specified using parameters such as Ra (Roughness Average) or Rz (average maximum peak-to-valley height). These measurements quantify the deviations in the surface texture from the ideal flat or smooth surface. A lower Ra or Rz value indicates a smoother and finer surface finish, while a higher value signifies a rougher and coarser surface.

Sub TypeApplicable MaterialsCosmetic AvailabilityVisual Appearance
As Machined Ra 1.6MetalsNoMachining marks are visible, light surface scratches are visible
As Machined Ra 3.2PlasticsNoMachining marks are visible, light surface scratches are visible

As Machined Parts

Aluminum CNC

Aluminum CNC



As Machined Design Considerations


Turning often results in a smoother surface due to the continuous single-point cutting action and more controlled tool geometry. Milling, with its multi-point cutting tools and complex tool paths, can yield a rougher surface finish, but it is highly dependent on the specific machining parameters, tool quality, and setup. Proper tool selection and optimization of cutting parameters can help improve the surface finish in milling operations.

Specifying a surface finish “as machined” is important because it defines the quality and texture of the workpiece’s surface directly after CNC machining. This helps set expectations for the surface finish without any additional post-processing, which can be crucial for parts with strict functional or aesthetic requirements.

Several factors can influence the surface finish as machined, including the cutting tool’s sharpness, the material being machined, the CNC machine’s accuracy and rigidity, feed rates, and cutting speeds. Operator skill and the choice of machining parameters play a crucial role in achieving the desired surface finish.

Let's get your projects started, together.