Chapter 24

Machining Processes: Milling, Broaching,

Sawing, Filing, and Gear Manufacturing

Milling Cutters and Milling Operations

Some basic types of milling

cutters and milling operations.

(a) Peripheral milling. (b) Face

milling. (c) End milling. (d)

Ball-end mill with indexable

coated-carbide inserts

machining a cavity in a die

block. (e) Milling a sculptured

surface with an end mill,

using a five-axis numerical

control machine.

Conventional vs. Climb Milling

Conventional vs. Climb Milling

Conventional:

Use on manual mills

Tooth engagement is not a

function of workpiece surface

characteristics

Contamination or scale (oxide

layer) on surface does not

adversely affect tool life

Climb:

Preferred on CNC machines

Holds workpiece in place

Improved surface finish

Less re-cutting of chips

Less power Required

Example

A end-milling operation is being carried out on a 300

mm-long, 100 mm-wide annealed mild steel block with

a feed f = 0.13 mm/tooth and a depth of cut of 3 mm.

The cutter is D = 0.5 in. in diameter, has 3 flutes

(teeth), rotates at N = 3000 rpm. Calculate the

material-removal rate.

Face-Milling Cutter (Shell Mill) with

Indexable Inserts

Effect of Insert Shape on Feed Marks on a

Face-Milled Surface

Types of Cutters

Knee Type Milling Machines (Horizontal

and Vertical)

CNC Milling Machines

5-axis Mill

Horizontal CNC Milling with Pallets

http://youtu.be/xZOiNdkJ8SU?t=1m50shttps://www.youtube.com/watch?v=TdxgqpMfIjA

Broaching

Broaching is a machining operation in which the tool

travels not the workpiece. It uses a long multiple-

tooth cutter to progressively remove more and more

material from the workpiece.

http://youtu.be/e26kCaPjX8E?t=1m19s

Hobbing

Gear cutting worm with cutting teeth that rotates in

sync with the rotating workpiece

https://www.youtube.com/watch?v=ZpJOEj-kX_o