23 Questions
What is the main purpose of a milling machine?
Removing metal with a rotating cutter
Which type of milling machine has a vertical column and knee mount?
Plain milling machine
What makes the plain milling machine suitable for heavy workpieces?
Rigid and sturdy construction
Which part of a column and knee type milling machine moves up and down accurately?
Knee
Why is the plain milling machine also known as a horizontal milling machine?
Rotating cutter moves horizontally
In which type of milling machine does the table move vertically, longitudinally, and crosswise against the rotating cutter?
Plain milling machine
What is the main advantage of a universal milling machine?
Performing helical milling works
In addition to table movements, what additional movement can the knee of an omniversal milling machine perform?
Tilting to a required angle
What is the primary function of the spindle in a vertical milling machine?
Rotating the cutters
Where is the arbour support located in a milling machine?
At the top of the column
Which part of a column and knee type milling machine supports all other parts of the machine tool?
Base
What is the purpose of the overhanging arm in a milling machine?
Supports the arbour from the top of the column
Which part of a universal milling machine allows for horizontal swivelling to perform helical works?
'T' - slots on the table
In down milling, the workpiece is moved in which direction relative to the rotation of the milling cutter?
Same direction
What type of milling is sometimes called conventional milling?
Up milling
Which milling operation leads to a wavy surface finish?
Up milling
What is used to hold arbors or cutters with smaller shanks than the spindle taper?
Collet
What is an attachment used for holding and indexing the work in cutting gears, ratchet wheels, keyways, etc.?
Indexing head attachment
Which type of dividing head is used for dividing the periphery of a piece of work into any number of equal parts?
Universal dividing head
What is the purpose of a high-speed milling attachment?
To improve accuracy of machining process
Which method tends to lift the workpiece from the fixtures due to its cutting force direction?
Up milling
What is used to transmit rotary motion to cutters held by collets?
Drawbolt
What causes vibration on the workpiece due to backlash error?
Differential indexing method
Study Notes
Milling Process
- Milling is a process of removing metal by feeding the work against a rotating multipoint cutter.
- The machine tool intended for this purpose is known as a milling machine.
Types of Milling Machines
- Classified according to the general design of the machine:
- Column and knee type
- Table type
- Planer type
- Special type
Column and Knee Type Milling Machine
- The column is mounted vertically upon the base.
- Knee is mounted on the accurately machined guide ways of the column.
- Saddle and table are mounted on the knee.
- Different types of column and knee type machines:
- Plain milling machine (rigid and sturdy, used for heavy workpieces)
- Universal milling machine (table can be swivelled by 45º, used for helical milling works)
- Omniversal milling machine (knee can be tilted to a required angle, used for machining helical grooves, reamers, and bevel gears)
- Vertical milling machine (spindle is positioned at right angles to the table, used for machining slots and flat surfaces)
Main Parts of Column and Knee Type Milling Machine
- Base: supports all the other parts of the machine tool, made of cast iron.
- Column: mounted upon the base, box shaped, houses the mechanism for providing drive for the spindle.
- Knee: slides up and down on the guide ways of the column, movements obtained by elevating screw mounted on the base.
- Saddle: mounted on the guide ways of the knee, moves in a cross direction.
- Table: moved longitudinally either by power or manually on the guide ways of the saddle, top surface has 'T' - slots.
- Spindle: located in the upper part of the column, receives power from the motor through belt, gears, and clutches.
- Overhanging arm: supports the arbour from the top of the column.
- Front brace: an extra support fitted between the knee and the overhanging arm.
- Arbor: supports different types of cutters used in the machine, drawn into the taper hole of the spindle by a draw bolt.
Size of a Milling Machine
- Specified by:
- Size of the table (length and width)
- Maximum lengths of longitudinal, cross, and vertical travel of the table
- Number of spindle speeds, number of feeds
- Spindle nose taper
- Power required
- Net weight of the machine
- Floor space required
- Type of the machine
Milling Operation - Peripheral Milling
- Classified into two types:
- Up milling (workpiece mounted on the table is fed against the direction of rotation of the milling cutter)
- Down milling (workpiece mounted on the table is moved in the same direction as that of the rotation of the milling cutter)
Cutter Holding Devices
- Depending on the design of the cutter, there are several methods of supporting milling cutters on the machine spindle:
- Arbor
- Collet
- Adapter
- Screwed on cutters
Milling Machine Attachments
- Intended for developing the range of operations, versatility, production capacity, and accuracy of machining process:
- Vertical milling attachment
- Universal milling attachment
- High speed milling attachment
- Slotting attachment
- Rotary table attachment
- Indexing head attachment
Indexing Head
- Indexing is the method of dividing the periphery of a piece of work into any number of equal parts.
- The attachment used for performing indexing is known as an indexing head.
- Three different types of indexing heads:
- Plain or simple dividing head
- Universal dividing head
- Optical dividing head
Learn about the process of milling, its applications, and the types of milling machines. Understand how milling machines are used for machining different types of surfaces and producing accurate results.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
