What is a CNC boring mill? This machine tool combines traditional boring mills with the most advanced technology: computer numerical control. How do these machines work and what are the advantages of using them? Would you like to buy one but are not sure how to choose?
What is a CNC boring mill?
The CNC boring mill, also called a boring machine, is a machine tool that combines traditional boring mills with CNC computer numerical control. A boring mill is used to machine holes in prismatic parts that require tight tolerances and a high-quality finish. This is what makes boring mills unique.
These machine tools consist of a bed carrying a rotary table on which the workpiece to be machined is clamped, and a vertical column along which a motorised head travels. The head drives the tool spindle, which holds the boring tools, known as boring bars.
When prismatic parts are to be machined, they are placed on the worktable and it is the cutting tool, held in the machine spindle, that moves. The spindle also provides the cutting speed required for the material being machined. When choosing a boring mill, consider the type of machining you want to carry out and the tools to be used, as boring is a costly process; machine time should therefore be kept to what is strictly necessary to avoid extra costs.
What can a CNC boring mill do?
A CNC boring mill is a versatile machine that can do much more than boring. In general, boring mills can enlarge existing holes and improve their quality, but a CNC boring mill offers much more. The operations it can perform include:
- Step boring.
- Reaming.
- Multi-edge boring.
- Single-edge boring.
These operations can be performed not only on a CNC boring mill but also on the other types of boring machine available, which may be vertical, horizontal or jig borers.
Vertical machines are named after the way the table rotates, horizontal machines because the tool is mounted on a horizontal spindle, while jig borers are used to machine parts such as dies, gauges and high-precision components.
Features of the CNC boring mill
A CNC boring mill can machine holes in horizontal and vertical directions, as the spindle holding the cutting tool, which machines horizontally, is parallel to the work surface. In addition, the machine head and its components generally move along three different working axes. The head moves the tool along the Z, X and vertical Y axes. The spindle is usually referred to as the C axis and, if the CNC boring mill has a rotary table, this is known as the B axis.
This type of machine is used, for example, for reaming work that could not be done on other machine tools because of cost, low efficiency or inaccuracy. It is also used for finishing and internal surface machining, and for working materials that are heat-sensitive or ductile.
In addition, these machines can machine large workpieces that could not be handled on other machine tools.
How a CNC machine works
All machines that run under computer numerical control share the same operating principle, even if they perform different tasks. These machines are equipped with a computer that controls the cutting tools and sets parameters such as speed and depth of cut. For the computer to know what to do, it must first be programmed or have a design preloaded on its hard drive.
Advanced software running on external computers has been developed for this purpose: computer-aided design and computer-aided manufacturing, known as CAD and CAM. For any CNC machine to work, whether a boring mill, milling machine or lathe, the operator must first design the part to be machined on this external computer.
Once the design has been created on the external computers, it must be loaded into the machine tool's control panel. The CNC boring mill's computer then determines the speed, depth and other parameters needed to carry out the required machining.
Finally, it is worth highlighting that any CNC machine can reduce machining times and lead times, increase production efficiency and cut labour requirements, because the processes are fully automated.