materi uas.pptx

7/28/2019 Materi UAS.pptx

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HEAT TREATMENT adalah :

Proses memanaskan dan mendinginkan suatu bahan untuk mendapatka

(struktur) guna meningkatkan kemampuan bahan tersebut sehingga berta

teknik dari bahan tersebut.

Parjan, SSiT., MT.

Tujuan dari HEAT TREATMENT adalah :

Untuk mencapai struktur dan sifat mekanis yang dikehendaki dari bahan

1. Mengeraskan

2. Melunakkan

3. Menghilangkantegangansisa

4. Menaikanketangguhan

5. dll


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Beberapa Proses Heat Treatment dan Kegunaannya,

1. Annealing

Memanaskansuatubahanhinggadiatassuhutransformasi(723C)kemudiand

perlahan-lahan.

Tujuannyaadalahuntukmelunakanbahan.

2. Stress Reliveing

Yaitu proses menghilangkan tegangan sisa dari suatu bahan dengan mema

ditahanbeberapawaktulaludilakukandenganpendinginanperlahan-lahan.

Tujuannyaadalahuntukmenghilangkantegangansisaselamaprosesfabrikasi.

Parjan, SSiT., MT.

3. HardeningMemanaskansuatubahanhinggadiatassuhutransformasi(723C)kemudiand

cepat,melaluimediapendinginsepertiair,oliataumediapendinginlainnya

Tujuannyaadalahuntukmengeraskanbahan.


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4. Aging (Precipitation Hardening)

Prosespemanasankembalibahanyangtelahdikeraskan,Suhupemanasannya

dibawahsuhutransformasieutektoid.

Tujuannya adalah untuk mengurangi kekerasan bahan sehingga keuletan (ke

tersebutdapatnaik.

Parjan, SSiT., MT.

Beberapa Heat Treatment Profile untuk Product Seals

Sec 15.0Temp OF

1800oF

76OF

0 60 120 Time Minute

ESTIMATED TOTAL CYCLE TIME : 3 HOURS

1800 +/- 25 F


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1750

1325

1150

150

ESTIMATED TOTAL CYCLETIM E: 22 HOURS

1750 +/- 25 F

1325 +/- 15 F

1150 +/- 15 F

790 1368020016013070100

Time (minutes)

Sec 10.0

Beberapa Heat Treatment Profile untuk Product Seals (Contd)

Parjan, SSiT., MT.


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Prosedur Kerja

Tap & Sney

Parjan, SSiT., MT.


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parjan, SSiT., MT.


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parjan, SSiT., MT.


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FIGURE 3.6.36 Cutting external

threads with a hand threading

die. Always start with the

chamfered side of the die. Cengage Learning 2012

FIGURE 3.6.35 Die stocks used tohold thread-cutting dies.

Cengage Learning 2012


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parjan, SSiT., MT.


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parjan, SSiT., MT.


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parjan, SSiT., MT.


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FIGURE 3.6.17

Threaddesignation

diagram for

Unified National

inch series

threads. Cengage Learning 2012

FIGURE 3.6.18A -20 bolt

with thread dimensions

and its corresponding

thread designation. Cengage Learning 2012

Thread Designation


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FIGURE 3.6.20An

M14x1.5 bolt with

thread dimensions

and its corresponding

thread

designation. Cengage Learning 2012

FIGURE 3.6.19 Thread

designation diagram for M-

series threads. Cengage Learning 2012


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Upright drill presses

The drive is very powerful and is

used for heavier work than a

sensitive drill press.

They can drill holes of 50 mm

diameter or more, and have the

capacity to drill holes of

38 mm diameter in thick steel.

It also consists of a base, column,

spindle and horizontal table

Parjan, SSiT., MT._STPI_CURUG


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Radial Drilling

Machines

These are the most versatile

drilling machines.

Machine size is determined by the

diameter of the column and the length of the arm, measured frthe centre of the spindle to the outer edge of the column.

Used for operations on large castings too heavy to be repositio

for drilling each hole.



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Parts of a twist drill bitThe following diagram illustrates the main parts of a twist d

bit and displays differently sized drill bits



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PARTS OF A TWIST DRILL



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PARTS OF A TWIST DRILL CONTD.



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PARTS OF A TWIST DRILL CONTD.


PARTS OF A TWIST DRILLCONTD


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PARTS OF A TWIST DRILLCONTD.



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Parjan, SSiT.,

MT._STPI_CURUG

Mal mata bor

Mal ini digunakan untuk mengukur panjang

bibir mata bor

S f f i


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Speeds and feeds for drills To ensure good work without damaging or breaking a drill b

it is important that the correct cutting speed and feed are use

The correct speed and feed are influenced by:

the diameter of the drill bit,

the type of metal being drilled and

the type of drill bit being used (carbon or high speed steel).

The cutting speed for the drilling operation is theperipheral

speed of a point on the surface of the drill in contact with the

work piece. Feed is the distance the drill advances into the work piece fo

each revolution.

Generally the larger the hole to be drilled, the lower the cutt

and feed speed.Parjan, SSiT., MT._STPI_CURUG


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Cutting Speeds

The following factors influence the choice of the best

cutting speed: kind of drill being used

composition and hardness of material

amount of feed

condition of machine

use of coolant (will increase cutting speed).

Usually drill presses are supplied with tables indicating

correct cutting speeds.



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Definitions Cutting Speed (v):-

Its the peripheral speed of the drill

v = (*D*N)/1000 where

D = dia of the drill in m

N = Speed of rotation in rpm

Feed Rate (f):-

Its the movement of drill along the axis (rpm)Depth of Cut (d):-

The distance from the machined surface to the drill a

d = D / 2



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Material Removal Rate:-

Its the volume of material removed by the drill per

time

MRR = ( D2 / 4) * f * N mm3 / min

Machining Time (T) :-

It depends upon the length (l) of the hole to be drill

to the Speed (N) and feed (f) of the drill

t = L / f N min



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Parts of the Lathe

Copyright The McGraw-Hill Companies, Inc.

Permission required for reproduction or display.

B

Headstock

Quick

Change

Gearbox

Tai

Carriage


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Copyright The McGraw-Hill Companies, Inc.Permission required for reproduction or display.


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Copyright The McGraw-Hill Companies, Inc.Permission required for reproduction or display.


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Cutting Speed, Feed, and Depth


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Cutting Speed

Rate at which point on work circumferencetravels past cutting tool

Always expressed in feet per minute (ft/min

or meters per minute (m/min)

Important to use correct speed for materialToo high: cutting-tool breaks down rapidly

Too low: time lost, low production rates


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Lathe Cutting Speeds in Feet and Meters per

Minute Using High-Speed Steel Toolbit

Turning and Boring

Rough Cut Finish Cut Threading

Material ft/min m/min ft/min m/min ft/min m/min

Machine steel 90 27 100 30 35

Tool steel 70 21 90 27 30 9

Cast iron 60 18 80 24 25 8Bronze 90 27 100 30 25

Aluminum 200 61 300 93 60 18


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Calculating Lathe Spindle Spee

Given in revolutions per minute Cutting speed of metal and diameter of

work must be known

Proper spindle speed set by dividing

CS (in/min) by circumference of work (in)

D

4xCS

D

12xCSr/min


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Example:

D

4xCSr/min

Calculate r/min required to rough-turn 2 in. diamet

piece of machine steel (CS 90):

1802

4x90

r/min

D

320xCSr/min Metric Formula


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CUTTING SPEED

DDiameter (mm)

NRevolutions per Minute (rpm)

m/min

1000

NDv

The Peripheral Speed of Work piece

past the Cutting Tool = Cutting SpeedParjan, SSiT., MT._STPI_CURUG

FEED


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FEED

fthe distance the tool advances for every

rotation of work piece (mm/rev)

f

Feed

DD

21


DEPTH OF CUT


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DEPTH OF CUT

perpendicular distance between machined surface and

uncut surface of the Work piece

d= (D1D2)/2 (mm)

dDepth

of Cut

DD 21


OperatingConditions


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Operating Conditions

Chip

Machine

surface

Workpiece

Depth of cutTool

Chuck

N

Feed (f )

Cutting speed

Depth of cut (d)


Three Important ElementsR i S d


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Rotating SpeedIt expresses with the number of rotations (rpm) of the chuck of a lathe. When the rotating high, processing speed becomes quick, and a processing surface is finely finished. Howeverlittle operation mistakes may lead to the serious accident, it is better to set low rotating spefirst stage.

Cutting DepthThe cutting depth of the tool affects to the processing speed and the roughness of surface. Wcutting depth is big, the processing speed becomes quick, but the surface temperature beco

high, and it has rough surface. Moreover, a life of byte also becomes short. If you do not knsuitable cutting depth, it is better to set to small value.

Feed (Sending Speed )The sending speed of the tool also affects to the processing speed and the roughness of surfWhen the sending speed is high, the processing speed becomes quick. When the sending splow, the surface is finished beautiful. There are 'manual sending' which turns and operatehandle, and 'automatic sending' which advances a byte automatically. A beginner must usmanual sending. Because serious accidents may be caused, such as touching the rotating charound the byte in automatic sending,.


Turning Operation


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g p

Schematic illustration of the basic turning operation, showing depth-of-

cut,d; feed,f; and spindle rotational speed,Nin rev/min. Cutting

speed is the surface speed of the work piece at the tool tip.



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Lathe Feed

Distance cutting tool advances along lengthof work for every revolution of the spindle

Feed of engine lathe dependent on speed of

lead screw for feed rod

Speed controlled by change gears inquick-change gearbox

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