UNIT I

INTRODUCTION

A. Background of study

Metal cutting process is a process that use to deform a metal material by cutting process. Cutting process use some cutting tool like endmill cutter and chisel cutter that the quality of work piece is so effected by the cutter (cutting tool), (azwar, 2013) investigated that a bad work piece is made by a dysfunction cutter, in terms of material or in terms of geometry (shape and angle of chisel).

Chisel damaged caused by so many factor, like rubbing between material and chisel made a high temperature chip that make chisel blunt. Cutting speed, length and deep of cut is make an effect to the temperature of chip. If rubbing between chip and an active cutter area was so high it will make the temperature high too, and it will decrease the cutter life time. That’s why coolant is so important to cooling down the temperature in machining process.

A conventional cooling process isn’t effective anymore for a stronger material because the process is need a long time. (Azwar, 2013) Investigated in a hard metal cutting process, heat that made by friction of work piece and cutter will be higher so conventional cooling process isn’t effective anymore.

A high preasure cooling process is a solution to make an effective cooling process. The high preasure that sprayed from noozle could reach the active chisel area that have the most high temperature, and automatically it could decrease the chance of blunt to the cutter and will increase the lifetime of the cutter and it is usefull to control the current chip, we also could increase the cutting speed (Helmy). (Mazurkiewicz et al. 1989) investigated that cooling process with high preasure could decrease scrape coefficient between chip and cutter main area, and will decrease cutting force and will decrease the cutter lifetime.

B. Research Question

Is the high preasure cooling process, could decrease the cutting forces, roughness surface, and the blunt to the cutter. Than conventional cooling process in traditional machining process

C. Purpose of study

To knowing how much cutting forces, workpiece and cutter temperature, chance of blunt, and surface roughness could decrease by using high temperature cooling process in traditional machine process.

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D. Significance of the study

As a reference for another research, for developing a knowledge about high preasure cooling process in machining process. And as an information to increase the quality of workpiece.

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UNIT IILITERATUR RIVIEW

A. Machining Process

Machining is the broad term used to describe removal of material from a workpiece, it covers several processes, which we usually divide into the following categories:

Cutting, generally involving single-point or multipoint cutting tools, each with a clearly defined geometry.

Abrasive processes, such as grinding. Nontraditional machining processes, utilizing electrical, chemical, and

optimal sources of energy.

It is important to view machining, as well as all manufacturing operations, as a system consisting of the workpiece, the tool and the machine.  The introduction topic in this section covers primers on topics like mechanics & shear bending in machining, and heat in machining.  The traditional machining includes primers on turning, milling, drilling, and grinding.  It also includes computer applications which are being supported by the primers. The non traditional machining includes primers on the topics like ECM, EDM, AFM, USM. (www. mfg.mtu.edu/cyberman/machining.html)

In the machining process, metal cutting with cold condition could stop the cutter blunt, reduce cutting temperature, and finaly it could increase cutter lifetime and surface of the workpiece. So use cooling fluid in machining process is so recommended, so there is no change of structure (Rochim)

B. Lathe Cutting tool

Tool Geometry. For cutting tools, geometry depends mainly on the properties of the tool material and the work material. The standard terminology is shown in the following figure. For single point tools, the most important angles are the rake angles and

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Pictures 1. Lathe cutting tool Geometry

the end and side relief angles. 

The back rake angle affects the ability of the tool to shear the work material and form the chip. It can be positive or negative. Positive rake angles reduce the cutting forces resulting in smaller deflections of the workpiece, tool holder, and machine. If the back rake angle is too large, the strength of the tool is reduced as well as its capacity to conduct heat. In machining hard work materials, the back rake angle must be small, even negative for carbide and diamond tools. The higher the hardness, the smaller the back rake angle. For high-speed steels, back rake angle is normally chosen in the positive range. There are two basic requirements for thread cutting. An accurately shaped and properly mounted tool is needed because thread cutting is a form-cutting operation. The resulting thread profile is determined by the shape of the tool and its position relative to the workpiece. The second by requirement is that the tool must move longitudinally in a specific relationship to the rotation of the workpiece, because this determines the lead of the thread. This requirement is met through the use of the lead screw and the split unit, which provide positive motion of the carriage relative to the rotation of the spindle.

C. Mill Cutting toolA milling cutter is a cutting tool that is used on a milling machine. Milling cutters

are available in many standard and special types, forms, diameters, and widths.The teeth maybe straight (parallel to the axis of rotation) or at a helix angle. The helix angle helps a slow engagement of the tool distributing the forces .The cutter may be right-hand (to turn clockwise) or left-hand (to turn counterclockwise).The figure shows a typical end milling cutter. Some of the terms used to identify the major features of a milling cutter are given in the figure.

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D. Cutting Condition

There is there variable for every traditional machining process it is deep of cut, cutting speed and feeding motion. To get the god product in term geometry, tolerant that we want, we need to notice some of trouble factor (Rochim)

E. Cutter Element

Body : is a part of cutter that formed to be edge of cut, or place of cutter Shank : is a part that use to paired with the machine Tool bore : that is a hole in the cutter that can be paired with the main

spindle of machine

F. Blunt and the damage of cutter

Life time of cutter isn’t always effected by geometry of cutter, every factor of machining process,

Kind of Material of workpiece Cuting condition Cooling process Kind of machining process

Blunt is a phenomenon that often happen in engginering process. Blunt isn’t the only one process, but so many process that could be happen in common or one by one. We could read the complicit of blunt to know the variable of blunt, like hardness, ductility, elasticity, tensile strength, stress, and surface structure that meet, like geometry,temperature etc.

G. Cooling Process

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Pictures 2. Endmill

Generally, cooling fluid is use to cooling and lubricating, cooling fluid could clean chip that patched in the cavity between an abrasive powder so will guarantee the forming process of chip. High temperature that happen in outer surface can be reduced so that will not destroy the structure of metalografi material product.

Cooling is so needed to reduce the blunt chance of cutter. Another income form cooling fluid is.

Reduce the temperature incrase Me a better surface of workpiece Clean the cutter from the chip Avoid the corrosion Reduce the lost of heat that made by friction Increase the lifetime of cutter Produce low force cutting

E. Cooling Method

Choose the usage of cooling is make an effect to the cutter or machining process. Way of cooling process that usually use is.

Manual; if the machine don’t have the cooling system, so cooling system is use with manual way. Like using brush or spray to be a media of coolant

Disbursed; cooling fluid disbursed to the active area of cutting using noozle, and the coolent is pumped from the coolant tank on machine

Atomized; coolant is sprayed to the active area of cutting like an atom particle

Pressed trough the line of the cutter; coolant is flowed trough the line of cutter

High preasure cooling process; cooling method that cooling fluid was sprayed by noozle to the workpiece with high preasure. Cooling fluid sprayed to the hottest point. With preasure 400kN/m2 or 4 bar until 130 bar.

Another research has investigated that the potential of using high preasure cooling process is better than conventional cooling process. Jet is use to separate chip with upside of cutter. Income of pointing the jet to the side of cutter is we coul control the flow of the chip, an combined with decreasing workpiece and cutter temperature.

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Kamruzaman investigated that this method isn’t just turndown the temperature, but it will save 50% of coolant usage. The purpose of using high preasure cooling process is:

Increase the life time of cutterCooling process by way cooling with high process so good

to applied in cutting process to stop the blunt rate of cutter

Protect from corrosion Cooling fluid is one part of cutting process that minimize

the corrosion. Improve quality of workpiece surface

High preasure cooling process could to clean a fragment of chip, that patched to the surface of workpiece when cutting process so the surface will be better than surface without high preasure cooling process.

F. Count the current rate The fluid rate could be counted by reading the different of preasure

technique on that pipe, where to got the different

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Picture 4. Cutter withoun coolant Cutter with high preasure cooling process

Picture 3. Cooling process with high preasure (kalpakjian)

preasure of that pipe made by sett the different of diameter with another diameter. This method is “bernoli law” and the function is.

P = the fluid pressure (pa) h = height of fluid= Density of the fluid (kg / cm3)

V = fluid velocity (m / s)g = gravity of the earth

Pitot pipe, orifice plate, venture pipe and flow nozzle use bernoli law. The Principe is change a little accelerate in the current fluid, so we will got a change of preasure that we can ne observed.

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Pictures 5. Bernoli law Principe

No

UNIT 3

A. The stages of the research can be seen in the flowchart below

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Finish

Conclusion

Date Analysis

Traditional machining process

1. Coolant High pressure

2. Variation nozzle: 0.7 mm, 0.9 mm, 1.2 mm, 1.5 mm

3. Depth of cut: 0.5mm, 1mm, 2mm

Preparation tools and materials

Purpose and significance of research

Literatur Library

START

Pictures 7. Pump (univ. syiah kuala)

B. Trial toolMachine and trial tool of these research and the research model will be described

in this part. Machining process was do in lab. Elementary machining process. And date withdrawal have been done in lab. Deformation Tech. Univ. Syiah Kuala.

a. Traditional lathe MachineSpec of the machine that used in this research is:

Merk/type : KNUTH Compass 250/1000BProduction : Jerman (2011)Power : 6,0 kWVolt : 400 voltFrequency : 50 Hz/3 phasen

b. Coolant pump Pump machine that we use in this reseach is:

Merk : Panasonic GP125Q : 35 L/minHmax : 30 mInput model : 220 V / 50 Hz

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Picturs 6. Lathe Machine (Univ. Syiah kuala)

c. High preasure cooling toolThe principle of high preasure cooling process that used in this research

could we see in picture bellow

Nozzle is the main component of this tool, with make a variation 4 nozzle with a different diameter 0,7 mm, 0,5 mm, 1,2 mm, and 1,5 mm. the shape of nozzle that we use is a cone nozzle with nozzle material that could strength until 690 bar.

d. Coolant Coolant that we use in this research is water soluble oil. Oil that have an

lubricant function mixed with water will make an emulsion fluid that have an oil particle wth size 5 u/ 8 micron meter will be spread and the light that touch it, will be deflected, and make the fluid have white color or another color suspended by fluid that mixed with it.

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Pictures 8. Cooling scheme

Pictures 9. Nozzle

e. Measuring tool

Microscope measuring is a tool to measure the blunt grow of cutter in the side that used to cutting the workpiece. And the spec is:

Tool name : Optic Microscope

Merk : Olympus

Type : GX71

Production : Japan

Zoom : 5x

Pictures 10. Optic Microscope (Univ. Syiah Kuala)

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