12 Common Types of Milling Machines and Their Functions
Different types of milling machines offer precision and efficiency while producing a wide range of products. They are essential tools in manufacturing that can be used to machine materials like metal, plastic, or wood, using cutting tools like end mills, face mills, and drills. Milling machines are made of high-quality cast iron, designed to have a variable speed capability, power feeds, and milling cutters that move along the x,y, and z axes.
Various operations such as slotting, keyway cutting, drilling, contouring, die sinking, and 3D milling are suitable for specific types of milling machines but the majority of them are capable of performing multiple tasks. Well, in this reading, we’ll explore the 12 common types of milling machines you should know and their functions.
Let’s get started!
Types of Milling Machines
The common types of milling machines include vertical milling machine, horizontal milling machine, universal milling machine, vertical knee type milling machine, bed type milling machine, CNC milling machine, tracer control milling machine, column milling machine, c-frame milling machine, drum milling machine, duplex milling machine, rotary milling machine.
Vertical Milling Machine
Vertical milling machines are precision tools used for shaping and fabrication, particularly in metals, wood, and plastics. These machines are equipped with computer numerical control (CNC) and can be operated manually or combined. The spindle of these machines is perpendicular to the table, allowing for slots, machining grooves, and flat surfaces.
The milling cutter is fixed on the spindle to work with angular surfaces. These machines offer more sophisticated cutting options than drill presses, with moveable tables and vises, vertical spindle movement, and rotatable turrets for the upper cutting head. Common operations include milling, slotting, and drilling or boring.
These types of milling machines are also known as horizontal milling machines, are more robust than hand millers and can be fed in vertical, cross, or horizontal directions. These machines use a rotating spindle to selectively remove material from a stationary workpiece. The main difference between these two types is the orientation of the spindle.
Vertical milling machines have a vertical spindle, while horizontal milling machines have a horizontal spindle. Feeding options include vertical adjustment, cross movement, and longitudinal rotation of the table. The main difference between these two types of milling machines is the orientation of the spindle.
Universal Milling Machine
The universal milling machine is a versatile standard tool that can be set up as a horizontal or vertical milling machine. It can be enhanced with attachments like an indexing head, slotting attachment, or rotary table. It is commonly used in shops to produce tooling like milling cutters, reamers, and drills. The universal mill can perform numerous machining operations, with a worktable that swivels up to 45 degrees for helical milling.
This machine can perform helical milling operations and can be expanded with additional attachments like slotting, rotary, vertical milling, and index head. It can produce various milling cutters, reamers, twist drills, spirals, bevels, spurs, and more, allowing for all the operations of a shaper machine with the universal milling machine.
Vertical Knee Milling Machine
Vertical knee milling machines, also known as turret milling machines, Bridgeport-type mills, variable-speed vertical milling machines, or knee-and-column milling machines, utilize rotary cutting tools to remove material from a workpiece. These machines differ from lathe machines, which rotate the workpiece and use a single-point tool.
The milling cutters are held vertically, and the workpiece is clamped horizontally on the machine’s worktable. Vertical knee mills are easy to operate, take up minimal space, and offer versatility, including CNC and manual operation on some models.
Bed Milling Machine
A bed-type milling machine is a type of milling machine that allows longitudinal movement in the X and Y axes, but lacks a knee for vertical movement. The worktable is placed on a fixed bed, allowing for a 3-axis range of movement.
The vertical axis (Z-axis) is provided by the vertical spindle, enabling the bed mill to move in a vertical direction. Although bed mills and vertical milling machines are similar in construction, bed-type milling machines are typically more rigid and preferred for larger projects and heavier workpieces.
CNC Milling Machine
CNC milling is a machining process that uses computerized controls and rotating multipoint cutting tools to produce custom-designed parts or products. These machines operate on three to five axes, creating slots, holes, and details in materials to turn them into vehicles or mechanical parts.
Modern CNC milling machines are assembled as both horizontal and vertical machining centers, and can be made with materials like plastics, ceramics, composites, and metals. Technical features include automatic tool changers, tool carousels & magazines, coolant systems, and enclosures to ensure smooth operation without manual interference.
Tracer Control Milling Machine
Tracer-controlled milling machines are essential tools for machining cams, grooves, and contoured surfaces in two dimensions. These machines are perfect for tracing elements and reproducing dies with complex and irregular shapes. The stylus energizes the oil relay system, operating the primary hydraulic system of the table.
Die sinking and other processes involving the machining of cavities can be done on three-dimension profilers or duplicators. Tracer-controlled milling machines were used in the 1970s by metal pattern shops producing cast iron patterns for automated foundries.
However, high-speed 3-axis CNC mills have replaced wooden patterns and talented wood patternmakers. Today, a CNC programmer using sophisticated manufacturing software takes the place of the patternmaker, avoiding the need for traditional wood patternmaking.
Column Milling Machine
Column milling machines are simple types of milling machines used for creating car parts. They consist of five key parts: worktable, head, saddle, knee, and over the arm, and use a vertically suspended drill. The column is attached to the base, allowing it to move vertically. The knee is mounted to guideways, allowing it to move horizontally. The column supports the knee, worktable, and overarm, housing the driving mechanisms for the spindle and table feed. These machines are suitable for various industries, including car parts.
C-Frame Milling Machine
C-frame milling machines are sturdy and powerful, ideal for industrial settings. They use a hydraulic motor and have a fixed spindle and knee structure, capable of vertical movement (Z-axis). These machines are used for mass production due to their high milling speed.
Drum Milling Machine
Milling machines are essential tools for industrial operations, with a drum milling machine being a prime example. This machine operates on a horizontal axis, rotating a vertical central drum. The cutters are face mills, with roughening and finishing cutters similar to those of a rotary-table miller. The drum-fixture rotates slowly, carrying the work against the rotating cutters.
The operation is continuous, with machined parts removed and new ones added after the cycle. This type of milling machine is commonly used for automotive cylinder heads and small shafts.
Duplex Milling Machine
Duplex solutions are machines that combine two machines opposite each other, working separately or as a single unit when the workpiece is machined with two spindles simultaneously. These machines can be either CNC machine tools or manual machines, and can move in both horizontal and vertical directions.
The main advantages of the duplex solution include a production increase of up to 50% compared to conventional solutions, improvements in part precision, one sole operator control, reduced space and investment requirements, and fast investment amortization due to high productivity. Duplex solutions can be configured in single working areas, pendulum working areas, or pallet changing systems.
CNC control is a crucial tool in the milling machine industry, allowing for precise positioning and cutting of round shapes. A rotary table is an attachment fastened to a milling machine, enabling precise positioning and cutting of round shapes. This machine can be operated manually or by CNC control.
It allows for 2D and 2.5D machining cycles around or on the end of a cylinder, with the tool always oriented radially to the centerline of the rotary axis. The rotary table milling machine consists of a circular table rotating on a vertical axis, allowing for the loading and unloading of workpieces continuously. This allows for a more efficient and accurate process in the production of precision parts.
