The milling machine is basically a tool used in shaping flat and irregular surfaces of solid materials, most specifically metals. Aside from this, the milling is also used for routing, cutting, planning, and drilling metals. Although basically, the general types of milling machines are vertical mills and horizontal mills, one vertical mill type has become uniquely popular- the Bridgeport milling machine.
The Bridgeport milling machine is a vertical milling machine manufactured by Bridgeport Machines Inc. Ever since its birth in the market in 1938, the Bridgeport milling machines have become well known for its small-sized and medium-sized vertical mills. In fact these milling have become so famous that machinists and hobbyists refer to vertical milling machines as simply Bridgeport milling machines.
Like any other vertical milling machine, the Bridgeport milling machine consists of a spindle that is vertically mounted. However, this milling machine is more similar to the turret mill than the bed mill. The similarities can be attributed to its smaller sizes and versatile functions. Like the turret mill, the Bridgeport milling machine consists of a table that can be moved perpendicularly and horizontally with the axis of the spindle. In this manner, cutting is easier to achieve, most especially in larger workpieces.
Today, the Bridgeport milling machine is still one of the top milling machines that is recognized by experts in the field. In addition, a number of various types of the Bridgeport milling machine are also out in the market. These milling machines are capable of performing various machine processes such as drill-tapping, horizontal turning, vertical pallet changing, jig grinding, and work holding, among others.
Drill-Tapping. This is the process of threading with the use of a tap or a die. Practically, the Bridgeport milling machine is capable of drilling holes of various sizes that are needed for tapping. Drilling the holes is very critical because the internal threads are dependent on the hole size, thus milling machines that can precisely drill exact hole sizes are required for this process.
Horizontal Turning. This is a process of metal cutting which is done by rotating the work piece on a spindle as a cutting tool is fed into it horizontally.
Vertical Pallet Changing. Changing pallets in worktables is a common setup in machining. The Bridgeport milling machine allows the vertical changing of pallets from the worktable to a standby station. This system makes the process faster and more organized.
Jig Grinding. In jig grinding, the highest degrees of finish and accuracy are a must. In this process, complex holes and shapes are the desired output s.
Work holding. This is the process of literally holding, supporting, and locating workpieces in place. This is an important function of any milling machine since the efficiency of the working process lies on the stability of the workpieces as well. In addition, a firm hold on the workpieces makes machining more convenient.
Some of the most popular Bridgeport milling machines include: Vertical Machining Centers, Horizontal Machining Centers, 5-Axis Machining Centers, and Knee Mills.
Fig.1. Bridgeport Milling Machine
Fig.2. Bridgeport Vertical Knee Mill