milling machine lecture

8/19/2019 Milling Machine Lecture

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MILLING

IE 262 Class Notes by Figen Eren 1


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MILLING

Milling is another basic machining process bywhich surface is generated progressively by

the removal of chips from a wor piece as it is

fed a rotating cutter!

Milling operations can be classified into two

broad categories

1. Peripheral Milling

2. Face Milling


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"

#wo forms of milling$ %a& peripheral milling' and %b& face

milling


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IE 262 Class Notes by Figen Eren (

Peripheral Milling


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Peripheral Milling

IE 262 Class Notes by Figen Eren )

#he a*is of the cutter rotation is parallel to the wor piece

surface to be machined in peripheral milling!

i!+p Milling

ii!,own milling


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Up milling

-lso called conventional milling,

- .heel rotation opposite of the feed

- #he chip formed by each cutter tooth starts out very thin and increases its

thicness

- #he length of the chip is relatively longer

- #ool life is relatively shorter

- Need more clamping force to hold the wor part still!


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IE 262 Class Notes by Figen Eren /

Down milling:

-lso called climb milling '

- .heel rotation is parallel to the feed

- #he chip formed by each cutter tooth starts out thic and leaves out thin

- #he length of the chip is relatively short

- #ool life is relatively longer

- Need less clamping force to hold the wor part still!


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0- MIIN3 45E-#I4N


#he basic form of peripheral

milling in which the cutter width

e*tends beyond the worpiece on

both sides


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Slotting (Slot milling):

8 Cutter width is less than the wor piece

width' creating a slot! If the cutter is very

thin' it can be used to cut a wor part intotwo' called saw milling.



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0aw milling

IE 262 Class Notes by Figen Eren 1:


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Sie milling:

Cutter' machines the side of the wor piece!

!


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Strale milling:

0imilar to side milling' but cutting taes on both sides

of the wor part simultaneously



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Form milling

8 In which milling teeth have a special profile that determines the shape of the slot that is cut in the wor

1"


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I E 2 6 2

C l a

s s

N o t

e s

b y

F i g

e n

E r e

n

1(

Face Milling


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IE 262 Class Notes by Figen Eren 1)

Face Milling

#he generated surface is at right angles to the cutter a*is and

is the combined result of actions of the portions of the teethlocated on both periphery and the face of the cutter! Most of

the cutting is done by the peripheral portions of the teeth' with

the face portions providing some finishing actions!

!on"entional #ace milling:

,iameter of tool is larger than wor part;s width!


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8 Partial #ace milling:

8 #he cutter overhangs from one side of wor part !in fig %b&

8 $n milling:

8 Cutters diameter is less than the wor part;s width' so aslot is cut into part! In fig <



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IE 262 Class Notes by Figen Eren 1/

Continue!!!

Pro#ile milling:

- form of end milling in which 4utside periphery of flat part is cut!

Poc%et milling:

0imilar to end milling' but the shape created is a shallow pocets in flat

surfaces

S&r#ace conto&ring:

- ball=nose cutter is fed bac and forth across the wor part to create acontoured surface perpendicular to the cutter .


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Face milling

Poc%et milling $n milling

Pro#ile milling


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IE 262 Class Notes by Figen Eren 2:

Milling !&tter

#he tool used in milling is nown as a milling cutter ' the cutting edges

called teeth! #ypes of milling cutters are related to the milling operations

can be classified as$

Plain milling c&tter:

+sed in peripheral milling operations

Cylindrical or dis shaped

>ave several straight or helical teeth on periphery +sed to mill flat surfaces

Sie milling c&tter:

0imilar to plain milling cutters

#eeth e*tend radial part way across one or both ends of cylinder toward

the center

elatively narrow


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Milling !&tter


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More Milling !&tter


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IE 262 Class Notes by Figen Eren 2"

Continue!!!

Form milling c&tter:

i. -nother peripheral milling cutter

= #eeth ground to a special shape to produce a surface having a

desired transverse contour' conve*' concave shape!

and facing narrow surfaces!

i!Concaveii!Conve*

iii!3ear tooth


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8 $n milling c&tter:

8 oos lie a drill bit' but it cuts with

peripheral teeth instead of it;s end! 8 >ave multiple teeth

8 +sed in milling slots' profiling

IE 262 Class Notes by Figen Eren 2(


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IE 262 Class Notes by Figen Eren 2)

Continue!!!Face milling c&tter:

>ave teeth on periphery and both sides

Made of >00


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*Slot Milling !&tter

*lot c&tter:

>ave teeth on periphery and both sides +sed for milling the wide groove of a #=slot

In order to use them' a vertical groove must first be made with

a slotting mill or an end mill to provide a clearance for the

shan

#=slot cutter must be fed carefully' because it cuts in ) surfaces


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Fly cutter

IE 262 Class Notes by Figen Eren 2/

•Single-pointed cutting tool with cutting endground to desired shape•Mounted in specialadapter or arbor •Fine feed must be used•Used in experimentalwork instead of aspecially shaped cutter


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-ngular cutter


•Teeth neither parallel nor perpendicular to cutting

axis•Used for milling angular surfaces

•Grooes! serrations! chamfers and reamerteeth

•"iided into two groups•Single-angle milling cutters•"ouble-angle milling cutters


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-ngular Cutter


•Single-angle•Teeth on angular surface•May or may not hae teeth

on flat•#$% or &'%•"ouble-angle

•Two intersecting angularsurfaces

with cutting teeth on both•()ual angles on both sideof lineat right angle to axis


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Inserted #ooth

IE 262 Class Notes by Figen Eren ":

-nother form of inserted=tooth

cutter consists of round' hardened

steel pins driven into holes in a

cast=iron body! #his cutter is also permanent in form' Fig! 212' as

broen teeth cannot be replaced?

and' when the teeth are worn

almost down to the body' the wholecutter is thrown away


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IE 262 Class Notes by Figen Eren "1

Milling Machine

#he milling machine supplies an accurate rotating spindle

for the cutter and a table %vise& to fi* and position the wor part! #here are two types of machines

+ori,ontal milling machine:

>ori@ontal spindle

,esigned for peripheral milling operations

-ertical milling machine:

Aertical spindle

,esigned for face milling operations

%In our ab!s we have this type of machines&


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>ori@ontal Milling Machine


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IE 262 Class Notes by Figen Eren ""

Aertical Milling Machine


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IE 262 Class Notes by Figen Eren "(

!lai#ication o# milling machine

!ol&mn an nee t/pe:

3eneral purpose Column' spindle' cutter' table' nee' base are the common

parts of the vertical and hori@ontal milling machines

In hori@ontal' arbor supports the cutter and an over arm

supports arbor In vertical' milling cutters can be mounted directly in the

spindle

= #he milling machines having only the three mutually

perpendicular table motions %*=y=@ a*es& are called plaincolumn and nee type

=Aertical type is especially well suited for face and end milling

operations


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Continue!!!=#wo more special column and nee machines are called

universal and turret type.

Universal type: >as a table that can be rotate in a hori@ontal plane to any

specified angle

Turret type:

>as duel heads that can be rotated about a hori@ontal a*is! #his permits milling to be done hori@ontally' vertically or at any

angle!


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IE 262 Class Notes by Figen Eren "/

#urret #ype Milling Machine


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IE 262 Class Notes by Figen Eren (:

ed #ype Milling Machine%2&

C ti


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IE 262 Class Notes by Figen Eren (1

Continue!!!

Simple':

>as single spindle

Duplex:

>as two spindles' permitting simultaneous milling of two

surfaces at a single pass

Triplex:

>as three spindles' permitting simultaneous milling of three

surfaces at a single pass

Planer t/pe milling machine:

+tili@e several milling heads

Can remove large amount of metal while permitting the table

and wor piece to move Duite slowly

4ften' only single pass is reDuired

= 3ood for heavy pieces


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IE 262 Class Notes by Figen Eren ("

C+##IN3 C4N,I#I4N0 IN MIIN3

#he rotational speed in milling is related to the

desired cutting speed at the surface of the wor piece by eDuation!

N =============

G ,

N rotational speed' revHmin cutting speed' ftHmin %mHmin&

, #ool diameter' ft %m&

C+##IN3 C4N,I#I4N0 IN MIIN3%cont!!1&


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IE 262 Class Notes by Figen Eren ((

% &

#he rotational speed in milling is related to the desired cutting speed at

the surface of the wor piece by eDuation! the feed f r in milling is

usually is given as feed per cutter tooth called chip oad? it represents

the si@e of the chip formed by each cutting edge!

f r N!n t ! f

f r feed rate' inHmin %mmHmin&

f chip load' inHtooth %mmH tooth&

n t number of teeth on cutter

M w! d! f r

d depth of cut' in %mm&

w width of cut' in %mm&

0- MIIN3


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IE 262 Class Notes by Figen Eren ()

0- MIIN3$

-

# m ====================

f r

- $ -pproach distance to reach full cutter depth

- √d!%,=d&

# m$ Machining time' min

F-CE MIIN3


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IE 262 Class Notes by Figen Eren (6

F-CE MIIN3$

2!-

# m ====================

f r

- $ -pproach distance to reach full cutter depth

- √w!%,=w&$ For partial Face milling

- ,H2 $ For conventional Face milling

milling machine lecture

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