How CNC Boring Mills Work

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Boring may sound dull, but think again. When you’re boring, it’s interesting (pun intended)! The intensity of boring heightens, especially when it’s computer-controlled.

Machines, like boring mills, have long been automated. Computer Numerical Control (CNC) boring mills produce custom parts or products in a wide array of applications among the different industries worldwide. But how do they work?

Let’s get into a system where boring is exciting! Here’s how CNC boring mills work!

Boring Terms and Definitions

To understand how boring mills work, let us first define some terms. The last three terms are subtractive manufacturing processes, the cutting of any workpiece into the desired shape and size.

Workpiece (or stock) refers to the object (metal, plastic, wood, etc.) you are working on with a tool or a machine.
Drilling is the cutting (using a multi-point cutter – a drill) of a hole of a circular cross-section into the workpiece.
Boring enlarges existing holes in a workpiece using a single-point cutter (boring bar).
Milling is machining flat and irregularly-shaped objects using a rotary cutting tool. According to Harvard Environmental Health and Safety, milling machines can be used to drill, bore, and cut gears, threads, and slots.

Boring Mill Types

Boring mills enlarge the already cast holes on a custom-made workpiece to serve a more intricate intended function. They have two types: vertical and horizontal. The vertical boring mills are great for small workpieces that are mounted to a chuck where it is rotated while the cutter is stationary.

On the other hand, the horizontal mills have a stationary workpiece and a rotating cutting tool attached to a spindle that moves horizontally, thus the name. The extending of the spindles to the headstock in boring mills becomes an advantage because users can reach small cavities of the workpieces for precision and accuracy.

CNC Boring Mill Components

Boring Software

Boring mills have evolved and are now equipped with CNC technology to be more efficient. With CNC, the operator or supervisor can create time-saving, cost-effective, and unlimited renderings or vector-based drawings through Computer-Aided Design (CAD).

Computer-Aided Manufacturing (CAM) software then converts the designs into G-codes, a program that gives detailed manufacturing instructions that computers perform. Therefore, CAM controls the boring mill that manufactures the custom-made parts with less to zero human intervention, reducing labor costs.

CNC machine operators or supervisors must have machining skills and basic understanding of CAD and CAM software.

Axes and Lubrication

Aside from the software, CNC boring mills have 3-5 axes that can create complex shapes and designs with precision, accuracy, and speed. These axes denote the boring mill’s movements: X and Y for the horizontal movement, Z for the vertical, and W for the diagonal movement. You also don’t have to worry about the integrity of the machine’s cutting tools, as CNC boring mills have automatic lubricating features.

The Boring Parts

The spindle, the anchor, and the insert are the three essential parts of a boring bar. The bar connects to the body of the mill through the anchor. The spindle rotates the cutting tool to create the force needed to cut into the workpiece. The insert, an extendable part of the spindle, slowly drives the cutting tool to the workpiece.

Overhang

Overhang is the distance by which your cutting tool sticks out of your anchor. Avoid overhangs when using boring mills because they have weaker connections and will result in less tight tolerance, less accurate cuts, and greater chances of errors. Reposition your workpiece when needed and only keep a short overhang.

Insert

The insert made of a grinding or cutting material, like concrete carbide, can also become a cutter. It may have different shapes and sizes that create different product configurations and finishes with boring mills.

Boring Applications and Products

CNC boring mills produce a more accurate finish to the holes and sustain the measurement of the workpiece through their extra stability and power. Additionally, they create well-crafted internal designs on workpieces rather than external ones.

The cylinder block of a car engine, for example, has many holes that are important for lubrication, temperature control, and engine stability. These holes were custom-made using boring mills. Manufacturers and hobbyists use them across industries for large- and small-scale projects, such as creating tunnels, prototypes for new products, gears, bearings, dowels, and screws.

Happy Boring Days

The above sections gradually presented how CNC boring mills work. These boring machines, their operation, and their mis-cut workpieces are expensive. Before getting one, assess the necessary aspects of your business operations to choose the CNC boring mill that best fits you to have lively boring days.