What Is a CNC Bar Feeder – Different Types of Bar Feeders & Bar Feeder vs Bar Puller


A bar feeder is a tool that is used to feed materials to a lathe, today we’ll go over different types of bar feeders and how they are programmed, as well as the difference between a bar feeder and a bar puller.

What Is a CNC Bar Feeder?

A CNC bar feeder is a device used to automatically load long bars of stock material into a CNC lathe for machining. The bar feeder is attached to the lathe’s headstock and feeds the bar stock into the lathe as the workpiece is cut. The bar feeder can hold a large quantity of stock material, allowing for continuous production runs without interruption for material loading. As the stock material is consumed by the lathe, the bar feeder automatically advances the next section of bar stock into the lathe, ensuring that the workpiece is always fully supported and that the length of material remaining is always sufficient to complete the next part. CNC bar feeders can be programmed to work in conjunction with the CNC lathe, communicating with the lathe’s control software to ensure accurate material positioning and stock management. This allows for improved productivity by reducing material setup and changeover times, and also improves the accuracy and consistency of the finished parts. CNC bar feeders are commonly used in high-volume production settings, where large quantities of identical machined parts are required. They can be used with a variety of stock materials, including metal bars, tubes, and other profile shapes, and are available in a range of sizes and configurations to suit different lathe types and applications.

What Is the Difference Between Bar Feeder and Bar Puller?

A bar feeder and a bar puller are both devices used for loading stock material into a CNC lathe for machining. The main difference between the two is how they grip and advance the stock material.

– A bar feeder is a device that automatically feeds long bars of stock material into a CNC lathe for machining. The bar feeder holds the bar stock and advances it into the lathe through the lathe’s spindle. The bar is typically gripped using a collet or clamp mechanism in the lathe’s headstock, and the bar feeder advances the material using a feed mechanism. Bar feeders are typically used for longer production runs and for stock material that is relatively straight and uniform.

– A bar puller, on the other hand, is a device that grips the stock material near the tip and pulls it into the lathe spindle. The bar puller can grip stock material that is not straight or uniform, and can also be used for shorter production runs. Bar pullers typically grip the stock material using a collet or other clamping mechanism that attaches to the tool turret or cross slide. As the stock material is cut, the bar puller retracts and pulls the remaining stock material into the spindle for further machining.


Bar feeders are used for continuous, longer production runs and require straight and uniform stock material, while bar pullers can handle shorter runs and more irregular stock shapes. Both devices improve efficiency, reduce material handling, and can be automated to work in concert with the CNC lathe’s programming system.

Different Types of Bar Feeders

1. Magazine bar feeders: These are designed to hold a magazine of bar stock and feed them into the lathe as required. Magazine bar feeders are typically used in high-volume production runs where long bars of material are used.

2. Hydrodynamic bar feeders: These use the pressure of oil or water to grip and advance the barstock. Hydrodynamic bar feeders are ideal for longer, thinner bars that may otherwise bend or deflect during feeding and machining.

3. robotic bar feeders: These use robots or other programmable automation systems to load and unload the lathe, monitor stock levels, and ensure that the process runs smoothly. Robotic bar feeders are ideal for large-scale production runs with high levels of automation and require minimal operator intervention.

4. pneumatic bar feeders: These use compressed air pressure to grip and advance the barstock. Pneumatic bar feeders are often used for shorter production runs, as they can be quickly and easily adjusted to handle different barstock diameters.

5. Servo-driven bar feeders: These use servo motors to control the bar’s feeding rate, ensuring precise positioning and consistent feed rates. Servo-driven bar feeders are typically used for high-precision production runs where accuracy and repeatability are critical.

How to Program the Bar Feeder?

Programming a bar feeder typically involves using the CNC controller to enter commands that control the operation of the feeder. 

1. Set up the bar feeder: Before programming the bar feeder, it must be properly installed on the lathe and connected to the CNC controller.

2. Select the appropriate program: Select the program that corresponds to the bar feeder being used and ensure that it is compatible with the machine’s operating system.

3. Enter material specifications: Enter the specifications of the material being used, such as diameter, length, and quantity.

4. Set feed rates: Enter the desired feed rates for the bar feeder’s feed mechanism, ensuring that they are appropriate for the material being used and the machining process.

5. Enter commands: Use the CNC controller to enter the necessary commands to control the bar feeder’s operation, such as start, stop, and pause commands.

6. Test the program: Run the program with the bar feeder attached and verify that the feeder is operating as expected and that the material is being fed accurately and consistently.

7. Make adjustments: Fine-tune the program as needed to ensure that the bar feeder is operating optimally, making adjustments for factors such as material type, diameter, and length.