This project is about the plasticity flow analysis of billet or workpiece in extrusion process by using three types of lubricant. There is oil palm empty fruit bunch or EFB bio-oil, mineral oil low viscosity and mineral oil high viscosity. Actually, plastic flow of metal is influenced by many factors, such as the lubricant's condition, friction, die shape and workpiece temperature. From the point of view of lubrication, the plastic flow of a metal could be used to predict the lubricant's performance and the friction constraint behavior between the tool and work piece.
In this study, the performance of different types of lubricant in the hot extrusion will be investigated. The evaluations and observations focused on the extrusion load, extrusion ratio, plasticity behavior, effective strain and velocity in plasticity flow, mapping of metal flow and experiment condition for three types of lubricants. An evaluation for velocity distributions on the surface of the billets will be solved by using the visioplasticity method. By using experimental method, all of lubricant will be test to analysis plasticity flow of billet or workpiece in extrusion process and to determine which lubricants shows satisfactory performance by reduces extrusion force and a better quality surface roughness.
PROBLEM STATEMENT
Based on the previous experiment evaluation in a journal by S. Syahrullail , S. Kamitani and K. Nakanishi that analyst of plasticity flow in cold extrusion process while using RBD Palm Olein shows that flow lines of billet at around the experimental surface creates better flow condition but RBD palm olein has possibility to create thick lubricant layer between tool and workpiece, and cause the surface roughness of extruded billet to become even coarser at working temperature of 15°C [1] . Then, overall observations of relative velocity and effective strain distribution in the deformation zone of billets show that RBD palm olein works as effective as Paraffinic mineral oil in its ability to reduce frictional constraint in cold metal forming. Therefore, an experiment will be prepared to creates more better flow line in hot extrusion process by using EFB bio-oil, mineral oil low viscosity and mineral oil high viscosity with suitable design of grid lines on the billet surface, achieved more effective strain and velocity and low extrusion load with suitable extrusion ratio between those lubricants.
OBJECTIVES
To design grid lines on the surface of the billets by using CNC Machine.
To evaluate plasticity flow of extrusion process by using three different of lubricants.
To mapping flow line of the billet for each three different of lubricants.
To determine extrusion load, effective strain and velocity by using three different of lubricants.
To compare the performance of each lubricants by different temperature.
SCOPES
The development of this project should be covered the following areas of studies:
Application fluid mechanics.
Plasticity theory must be included to evaluate the flow line or plasticity flow on the billet surface and effective strain and velocity in metal forming process.
Application of automatic tool path generation system
EDM wire cut machine, milling machine and height which used to prepare billets and draw grid lines on the billets surface as desired design.
Manufacturing process
Hot extrusion and vertical extrusion should be applied in case for determining influence of extrusion ratio of 3 and extrusion load for this project.
Tribology principles
Application of tribology that's includes application of the principles friction, lubricants and wear. This project focused on the principle of lubricants which about performance of the three different lubricants to make sure that between those three lubricants have low extrusion load and ability to flow easily during extrusion process.
CHAPTER 2
LITERATURE REVIEW
2.1 INTRODUCTION
During complete this project, especially while preparation of billets or workpieces, preparation of die, setting up the experiments and application of three lubricants or EFB Bio-oil, Mineral oil High Viscosity and Mineral Oil Low Viscosity.
So, this chapter will provided and summarizing of all theories that used in completing this project. All of application theories have been included in the project are probably from previous subjects that had been learned in the class before. Mostly, all of the literature reviews were obtained from many academic resources such as journal, articles and books.
2.1 MANUFACTURING PROCESS
In this project, manufacturing process will be applied to prepare the billet and die. While preparing the billet and die, there are some of machine will be used, such as EDM wire cut, Conventional Milling machine,
2.1.1 Conventional Milling Machine
While preparing the gridlines on the billets, a milling machine is used. the milling machine was used to prepare the grip for the billets. Before uses the milling machine, knowledges of functions and methods how to work the milling machine is important. A milling machine is a machine tool used for the complex shaping of metal and other solid materials. Its basic form is that of a rotating cutter or endmill which rotates about the spindle axis (similar to a drill), and a movable table to which the workpiece is affixed. That is to say, the cutting tool generally remains stationary (except for its rotation) while the workpiece moves to accomplish the cutting action. Milling machines may be operated manually or under computer numerical control (cnc). Milling machines can perform a vast number of complex operations, such as slot cutting, planing, drilling, rebating, routing, etc. Cutting fluid is often pumped to the cutting site to cool and lubricate the cut, and to sluice away the resulting chips.
2.1.1.1 Types of Milling Machines
There are two main types of mill: the vertical mill and the horizontal mill. In the vertical mill the spindle axis is vertically oriented. Milling cutters are held in the spindle and rotate on its axis. The spindle can generally be extended (or the table can be raised/lowered, giving the same effect), allowing plunge cuts and drilling. There are two subcategories of vertical mills: the bedmill and the turret mill. Turret mills, 8 like the ubiquitous Bridgeport, are generally smaller than bedmills, and are considered by some to be more versatile. In a turret mill the spindle remains stationary during cutting operations and the table is moved both perpendicular to and parallel to the spindle axis to accomplish cutting. In the bedmill, however, the table moves only perpendicular to the spindle's axis, while the spindle itself moves parallel to its own axis. Also of note is a lighter machine, called a mill-drill. It is quite popular with hobbyists, due to its small size and lower price. These are frequently of lower quality than other types of machines, however A horizontal mill has the same sort of x-y table, but the cutters are mounted on a horizontal arbor across the table. A majority of horizontal mills also feature a +15/-iS degree rotary table that allows milling at shallow angles. While endmills and the other types of tools available to a vertical mill may be used in a horizontal mill, their real advantage lies in arbor-mounted cutters, called side and face mills, which have a cross section rather like a circular saw, but are generally wider and smaller in diameter. Because the cutters have good support from the arbor, quite heavy cuts can be taken, enabling rapid material removal rates. These are used to mill grooves and slots. Plain mills are used to shape flat surfaces. Several cutters may be ganged together on the arbor to mill a complex shape of slots and planes. Special cutters can also cut grooves, bevels, radii, or indeed any section desired. These specialty cutters tend to be expensive. Simplex mills have one spindle, and duplex mills have two. It is also easier to cut gears on a horizontal mill. A more complex form of the milling machine is the Universal milling machine, in which the rotating cutter can be oriented vertically or horizontally, increasing the flexibility of the machine tool. The table of the universal machine can be swiveled through a small angle (up to about 15 degrees), enabling the axis of the spindle to coincide with the axis of a helix to be milled with the use of a gear driven indexing attachment.
2.1.2 ELECTRIC DISCHARGE MACHINING WIRE CUT
In this project, the taper die and billet will be cut by the electric discharge machining (EDM) wire cut. Electric discharge machining wire cut is used to make a through hole in a workpiece in through which to thread the wire in Wire-cut EDM machining. The small hole drilling head is mounted on wirecut machine and allows large hardened plates to have finished parts eroded from them as needed and without pre-drilling. There are also stand-alone small hole drilling EDM machines with an x-y axis also known as a super drill or hole popper that can machine blind or through holes. EDM Drills bore holes with a long brass or copper tube electrode that rotates in a chuck with a constant flow of distilled or deionized water flowing through the electrode as a flushing agent and dielectric. The electrode tubes operate like the wire in wire-cut EDM machines, having a spark gap and wear rate. Some small-hole drilling EDMs are able to drill through 100 mm of soft or through hardened steel in less than 10 seconds, averaging 50% to 0% wear 10 rate. Holes of 0.3 mm to 6.1 mm can be achieved in this drilling operation. Brass electrodes are easier to machine but are not recommended for wire-cut operations due to eroded brass particles causing "brass on brass" wire breakage, therefore copper is recommended.
2.2 MECHANICAL PROPERTIES
2.2.1 TAPER DIE
For tapper die, the types of metal that used in preparing this tapper die is SKD 11. In the table below, the material properties for Alloy steel SKD 11.
DATA TABLE FOR:STEEL GRADES:TOOL STEEL AND HARD ALLOY:SKD11
Chemical composition % of the ladle analysis of grade SKD11
C(ï¼…)
Si(ï¼…)
Mn(ï¼…)
P(ï¼…)
S(ï¼…)
Cr(ï¼…)
Mo(ï¼…)
V(%)
1.40-1.60
Max 0.40
Max 0.60
Max 0.030
Max 0.030
11.0-13.0
0.80-1.20
0.20-0.50
Mechanical properties of grade SKD11
Technological properties of grade SKD11
Hardness and heat treatment specification of grade SKD11
Annealing hardness
HBS
Cold pull hardness
HBS
Preheating temperature
℃
Quenching temperature
℃
Holding time
min
Hardening medium
Temper temperature
℃
After tempering hardness
≥HRC
salt-bath furnace
controlled atmosphere furnace
235
262
788
1191
1204
5～15
air cooling
522
60
Steel plate/Sheet
thickness / mm
σb
MPa
σs
≥/MPa
δ
Samples from the standard for 50 mm (2 in)
180 ° of cold bending test
longitudinal
horizontal
Hot-rolled/Cold rolling:5 - 150
520
415
16～18
2a
3.5a
Note:
(1) listed in the table apex diameter (d), to steel thickness (a) multiples said.
(2) in the ASTM A6 standard specified scope can meet any additional conditions.
(3) from the standard for 50 mm (2 in).
Mechanical properties
Mechanische Eigenschaften
Caracteristiques mecaniques
ReH Minimum yield strength / Mindestwert der oberen Streckgrenze / Limite d'elasticite minimale
Rm Tensile strength / Zugfestigkeit / Resistance a la traction
A Minimum elongation / Mindestwert der Bruchdehnung / Allongement minimal
J Notch impact test / Kerbschlagbiegeversuch / Essai de flexion par choc
SKD11 steel description:
Step Shaft: steel plate/sheet,coil,round bar,flat bar,tube/pipe,Profiled forgings
SKD11 steel Specifications or Size:
Round bar:
Diameter : 1mm-2000mm
Square bar:
Size: 50mm * 50mm-600mm *600mm
Plate steel/flat bar:
Size: Thickness: 0.1mm-800mm Width: 10mm to 1500mm
Tube/pipe:
Size: OD: 6-219mm WT: 1-35 mm.
Cold-rolled sheet: Thickness: 2-5mm Width:1000mm Length: 2000mm
Hot-rolled sheet: Thickness:6-80mm Width: 210-610mm
Length: We can supply any length based on the customer's requirement.
Forging/hot rolling/ extrusion of steel.
Forging: Shafts with flanks/pipes/tubes/slugs/donuts/cubes/other shapes
Finished goods condition: hot forging/hot rolling + annealing/normalizing + tempering/quenching + tempering/any conditions based on the customer's requirement
Surface conditions: scaled (hot working finish)/ground/rough machining/fine machining/based on the customer's requirement
Furnaces for metallurgical processing: electrode arc + LF/VD/VOD/ESR/Vacuum consumable electrode.
Ultrasonic inspection: 100% ultrasonic inspection for any inperfections or based on the customer's requirement.
UTS according to SEP 1921 C/c,D/d,E/e;A388 or GB/T 6402
Excellent service for all kinds of industries, with advantages of technologies, equipment and price.
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2.2.2 BILLET OR WORKPIECE
2.3 VISIOPLASTICITY METHOD
Visioplasticity is a method of obtaining information on material flow by using experimentally determined displacement of velocity fields. This method has gained greater importance in the past decade because of quantitative measurements of nodal point displacement in stepwise deformation, describing the material flow pattern. The material flow can be determined by comparing un-deformed and deformed grids [2] .
The plastic flow velocity, strain rate components, effective strain rate, and effective strain in the deformation zone were calculated by using the equations, (1) to (5). Since the analytical calculation procedure was explained in the earlier publications [5], it is omitted here.
Figure : Coordinate system used in visioplasticity analysis.
Flow function
Ψi = Xi |V0|
Velocity component (velocity in x-direction: u, velocity in y-direction: v)
The strain rate component (s-1)
The effective strain rate (s-1)
The effective strain (time integration value of the effective strain rate along the flow line)
In the equations, V0 is the velocity of the press ram in mm/s, and Xi is the distance of the i-th flow line from the y coordinate axis (X=0), in mm, in the region where deformation does not occur.
2.4 HOT EXTRUSION
Metal forming processes, also known as mechanical working processes, are primary shaping processes in which a mass of metal or alloy is subjected to mechanical forces. Under the action of such forces, the shape and size of metal piece undergo a change. By mechanical working processes, the given shape and size of a machine part can be achieved with great economy in material and time [3] .
In metal forming processes, there are two types of metal forming process that are cold and hot metal forming. Thus, in this project, the hot metal forming or extrusion process will be applied during the experiments. Hot working may be explained as plastic deformation of metals and alloys at such a temperature at which recovery and recrystallisation take place simultaneously with the strain hardening. Such a temperature is above recrystallisation temperature. Properly done hot working will leave the metal or alloy in a fine grained recrystallised structure.
Typical Hot Working Temperatures
Steels 650-1050°C
Copper and alloys 600-950°C
Aluminium and alloys 350-485°C
2.5 TRIBOLOGY
Tribology plays an important role in manufacturing. In metal-forming operations, friction increases tool wear and the power required to work a piece. This results in increased costs due to more frequent tool replacement, loss of tolerance as tool dimensions shift, and greater forces required to shape a piece. The use of lubricants which minimize direct surface contact reduces tool wear and power requirements.
2.6 LUBRICANTS
CHAPTER 3
METHODOLOGY
3.1 INTRODUCTION
By using information from related journals and book, the theory of plasticity flow in extrusion process will be applied in this project. The billet will be showed plastic deformation in terms of stresses, strains, and loads or to physical explanations of plastic flow. For this project the experiment method will be applied to get an accurate result. In this experiments method, EFB bio-oil, mineral oil low viscosity and mineral oil high viscosity will applied on the surface of work piece. For every types of lubricant that used in experiments will test four times to get more accurate results.
The experiments were carried out by hot extrusion process in which velocity distribution in a steady state extrusion could be measured by the visioplasticity method. The main components are die and cylinder, plane plate tool and billet (work piece) with circular or rod shape. The die and cylinder is a unit of construction part. The plane plate tool works as the plane plate tool and also as the container wall. Preparation for work piece will go through cutting, annealing, hardness test, gridline and polish process. The material of work piece is aluminum. Preparation of die will go through cutting, hardness test and polish process.
Then, test lubricant was applied on the surface of plane plate tool that has a contact with the work piece and was noted as the experimental surface of plane plate tool. The performance of lubricants based on the surface roughness and extrusion force on the billet or work piece. The lubricants will be test in four times to get more accurate results.
3.1 EXPERIMENT PROCEDURE
In this methodology segments, all of process in completing this project will be explain. The project starts with literature review and research about plasticity flow in hot extrusion process. This project includes a review of plasticity flow theory and mostly based on subject Fluid Mechanics that had learned before. This research had been done smoothly by using internet, books and others resources. Then, preparation of die and billets by using manufacturing process. billetmengenal pasti tajuk projek, mencari maklumat mengenai tajuk projek, mengkaji dan mngenalpasti masalah produk, mengubahsuai dan merekabentuk produk, menentukan saiz untuk produk, membina produk dengan menggunakan perisian SolidWorks, pemilihan bahan yang sesuai, hasil produk yang telah dibina dan juga menganalisis produk yang telah direkabentuk dengan berdasarkan kepada lukisan yang telah dibina dalam perisian SolidWorks.
