Unlike lathes, where the workpiece rotates, milling machines use a rotating cutter to operate. Most models feature self-contained electric motors, coolant systems, digital readouts, variable spindle speeds, and power-driven table feeds. In addition to surface machining, they can also be used for drilling, boring, gear cutting, and creating slots or pockets.
Milling Machines: Types, Tips, and Accessories
Milling machines are used to machine solid materials like metal, plastic, and wood. They are especially effective for producing flat or irregular surfaces.
Diagram of a Milling Machine
Horizontal and Vertical Mills
Horizontal mills are designed so the cutters are mounted on a horizontal spindle. They are equipped with a rotary table, allowing for milling grooves, slots and other heavier cuts at several angles. They are commonly identified as a universal milling machine.
Vertical mills are designed with a spindle axis that is vertically oriented. The spindle can be extended, or the table raised and lowered, allowing for plunge cuts and drilling. There are two types of vertical mills:
- Bed mills, which have a fixed table and a head that moves in a Z-axis. This allows for additional weighted parts to be machined.
- Turret mills, which can be moved perpendicular and parallel to the spindle axis.
Milling Machines
Knee Milling Machines
Knee milling machines are used to cut internal or external features of a workpiece using a rotating milling cutter. They support a wide range of operations, including milling, drilling, tapping, facing, keyway cutting, pocketing, and slotting. These machines feature a T-slotted worktable with three slots for securely clamping the material during machining.
Mill Drill Machines
Mill drill machines are used for precise boring, drilling, milling, and tapping operations. They feature spindles capable of handling side-cutting loads and rigid milling tables with X-Y movement. Lightweight and compact, they are ideal for applications where space is limited.
3-in-1 Machines
3-In-1 Machines combine milling, drilling, and lathing in one convenient unit.
Computer Numerical Controlled (CNC) Milling Machines
Computer Numerical Controlled (CNC) milling machines use end mills to remove and shape material during milling operations. They are programmed with alphanumeric codes—commonly called G-codes—that direct the machine to follow specific cutting patterns or perform designated functions. CNC milling machines operate in 3- or 4-axis configurations, enabling vertical, cross, and longitudinal movement, as well as optional 4-axis rotary positioning.