What is CNC Turning?
CNC Turning is a manufacturing process in which bars of material are held in a chuck and rotated while a tool is fed to the piece to remove material to create the desired shape.
A turret (shown center), with tooling attached, is programmed to move to the bar of raw material and remove material to create the programmed result. This is also called “subtraction machining” since it involves material removal.
If the center has both tuning and milling capabilities, such as the one above, the rotation can be stopped to allow for milling out of other shapes.
- The starting material, though usually round, can be other shapes such as squares or hexagons.
- Depending on the bar feeder, the bar length can vary, affecting how much handling is required for volume jobs.
- CNC lathes or turning centers have tooling mounted on a turret, which is computer-controlled. The more tools the turret can hold, the more options are available for complexities.
- CNC’s with “live” tooling options can stop the bar rotation and add additional features such as drilled holes, slots, and milled surfaces.
- Some CNC turning centers have one spindle, allowing work to be done all from one side, while other turning centers, such as the one shown above, have two spindles, a main and sub-spindle. A part can be partially machined on the main spindle, moved to the sub-spindle, and have additional work done to the other side of this configuration.
- There are many different kinds of CNC turning centers with various types of tooling options, spindle options, outer diameter limitations, power and speed capabilities that affect the types of parts that can be economically made.
Is my part a good fit for CNC turning?
While a lot of factors go into determining if a part can be made most cost-effectively on a specific CNC turning center, some things we look at are:
- How many parts are needed, short-term and long-term? CNC turning centers are generally suitable for prototypes to short-run volumes.
- What is the largest OD on the part? For the CNC turning centers at Pioneer Service, the maximum OD for collected (bar feed-capable) parts is 2.5.”
- Parts over 2.5″ OD are chucked individually, which depending on volume, can contribute to the price.
- Parts under 1.25″ OD and medium to high volume may better fit the Swiss screw machines.
- If a part can be made both on the CNC turning center and on a 32 mm Swiss Screw Machine, factors such as projected volume and lead-time are critical for making the best call on which to use.
When it comes to machining parts, there are a lot of variables. RJC can help you determine the best way to have your parts made. Contact us for help with your requirements.