Vertical Milling
Introduction
Vertical milling is a machining process where a cutting tool, often called a Milling cutter, removes material from a workpiece while the workpiece is oriented vertically. This process is most commonly used in metalworking, but it can also be applied to other materials such as wood or plastic.
History
The concept of vertical milling has been around for centuries, with the earliest examples dating back to the ancient Egyptians who used a primitive form of this technique to shape stone. However, it was not until the Industrial Revolution in the 19th century that vertical milling became a widely used industrial process. The invention of the steam engine provided the necessary power to drive large milling machines, and the development of interchangeable parts during this period further increased the efficiency and versatility of the milling process.
Types of Vertical Milling Machines
There are several types of vertical milling machines, each with its own unique features and capabilities. The most common types include:
Turret Mill
A turret mill has a stationary spindle and the table is moved both perpendicular and parallel to the spindle axis to accomplish cutting. The most common example of this type is the Bridgeport, named after the company that designed and produced it.
Bed Mill
A bed mill, on the other hand, has a bed that can be moved only perpendicular to the spindle's axis, while the spindle itself moves parallel to its own axis.
CNC Mill
CNC mills, or Computer Numerical Control mills, are automated milling machines that make industrial parts without direct human assistance. They use coded instructions that are sent to an internal computer, which allows factories to fabricate parts accurately and quickly.
Vertical Milling Operations
Vertical milling operations can be classified into two broad categories: face milling and peripheral milling.
Face Milling
In face milling, the cutting action occurs primarily at the end corners of the milling cutter. Face milling is used to cut flat surfaces (faces) into the workpiece, or to cut flat-bottomed cavities.
Peripheral Milling
In peripheral milling, also known as slab milling, the axis of cutter rotation is parallel to the workpiece surface. It is used primarily to make narrow, deep cuts, known as slots or grooves.
Advantages and Disadvantages of Vertical Milling
Like any other machining process, vertical milling has its own advantages and disadvantages.
Advantages
Some of the advantages of vertical milling include:
- Versatility: Vertical mills are capable of performing a wide variety of operations, from simple slot and keyway cutting to more complex operations such as contouring and die sinking. - Precision: Vertical mills are known for their precision, capable of producing parts with very tight tolerances. - Automation: With the advent of CNC technology, vertical mills can be automated, reducing the need for manual operation and increasing productivity.
Disadvantages
Despite these advantages, there are also some disadvantages to vertical milling:
- Limitations on workpiece size: Due to the vertical orientation of the spindle, the size of the workpiece is limited to what can fit on the table. - High initial cost: Vertical milling machines are typically more expensive than their horizontal counterparts.
Conclusion
Vertical milling is a versatile and precise machining process that has a wide range of applications in the manufacturing industry. Its ability to perform a variety of operations and its high level of precision make it a valuable tool for any machine shop.