Page 94 - CITS - Fitter - Trade Theory

FITTER - CITS

1 Vertical Milling Machine:

• In a vertical milling machine, the spindle axis is vertically oriented.
• The cutting tool moves up and down along the Z-axis.
• Vertical milling machines are commonly used for face milling, end milling, drilling, and tapping operations.
• They are suitable for machining workpieces with vertical surfaces or features.
2 Horizontal Milling Machine:

• In a horizontal milling machine, the spindle axis is horizontally oriented.
• The cutting tool moves side to side along the X-axis.
• Horizontal milling machines are suitable for slotting, slab milling, and contouring operations.

• They are ideal for machining workpieces with horizontal surfaces or features.
3 Universal Milling Machine:
• A universal milling machine combines the features of both vertical and horizontal milling machines.
• It offers greater versatility and flexibility in machining operations.
• Universal milling machines can accommodate workpieces of varying sizes and shapes.

• They are capable of performing a wide range of milling tasks, including face milling, end milling, and boring.
4 CNC Milling Machine:
• CNC milling machines are equipped with computer numerical control (CNC) systems for precise control of
machining operations.
• They offer automation, programmability, and high accuracy in milling operations.
• CNC milling machines can be vertical, horizontal, or universal in configuration, depending on the machining
requirements.
Working Principle of milling machine:
The workpiece can be fed vertically, longitudinally, or diagonally. The spindle speed, table feed, depth of cut, and
direction of cutter rotation are the most important process factors.
1 Setup and Preparation: The workpiece is securely clamped or mounted onto the machine table using various
workholding devices such as clamps, vises, or fixtures. Proper setup ensures that the workpiece is stable and
positioned accurately for machining.
2 Tool Selection of Cutting: A suitable cutting tool is selected based on the desired machining operation,
material type, geometry, and surface finish requirements. Common types of cutting tools used in milling
machines include end mills, face mills, drills, reamers, and taps.

3 Tool Mounting: The selected cutting tool is mounted onto the spindle of the milling machine using a tool
holder such as a collet, chuck, or tool holder. The tool holder securely holds the cutting tool in place and allows
for precise positioning and orientation during machining.

4 Selection of Machining Parameters: Machining parameters such as cutting speed, feed rate, depth of cut,
and coolant usage are selected based on the material being machined, tool geometry, and desired
machining outcomes. These parameters determine the efficiency, accuracy, and surface finish of the machining
process.
5 Movement of Cutting Tool: The milling machine’s spindle rotates the cutting tool at high speeds while the
workpiece remains stationary or moves relative to the tool. Depending on the type of milling machine and
machining operation, the cutting tool may move along multiple axes to achieve the desired machining path and
geometry.
6 Material Removal: As the rotating cutting tool engages with the workpiece, it removes material by shearing,
cutting, or scraping. The cutting edges of the tool generate chips or swarf, which are evacuated from the
machining area by the coolant or chip conveyor.

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CITS : CG & M - Fitter - Lesson 12 CITS : CG & M - Fitter - Lesson 12