OPTIMIZED DIE STRUCTURE DESIGN OF PLASTIC INJECTION MOULD USING FEM TECHNIQUE

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International Journal of Research and Innovation (IJRI)

OPTIMIZED DIE STRUCTURE DESIGN OF PLASTIC INJECTION MOULD USING FEM TECHNIQUE

Choppara. Yasudas, D.Gopichand

Mother Theresa Institute of Technology(mist) Sanketika Nagar Sathupally Khammam,India

*Corresponding Author: Choppara. Yasudas, Mother Theresa Institute of Technology(mist) Sanketika Nagar Sathupally Khammam,India Published: Sep 22, 2014

Volume No: IIssue No. : III

Citation:Choppara. Yasudas, D.Gopichand (2014) Optimized Die Structure Design of Plastic Injection Mould Using Fem Technique

Introduction

Air coolers also called evaporative coolers are used for cooling purposes. They are different from air conditioners in the sense air conditioners use refrig-eration cycle principle whereas air coolers use the evaporation of water principle. There are five main evaporative cooler parts, with each of these being composed of other parts or pieces.The first part is the Blower which creates the airflow into and out of the cooler.Then there are the pads which filter and cool the air. These pads are attached to the side grill; this grill is supported with side grill pillars and

Abstract

A die is a specialized tool used in manufacturing industries to cut or shape material mostly using a press. Like molds, dies are generally customized to the item they are used to create. Products made with dies range from simple paper clips to complex pieces used in advanced technology.

The Aim of this thesis work is to reduce weight and cost of the injection mold by removing unwanted materials and using low cost materials at non-stress region areas.

A general large size model will be prepared to design the mold structure using theoretical method.

Complete level of mold parts and assembly will be prepared to conduct analysis.

Structural analysis will be conducted on mould to find stress locations and non-effective locations.

Modifications will be done on mold according to obtained results.

Analysis will be carried out on modified mold for evaluation and various materials will be applied in ANSYS at non- stress effected areas to reduce the cost.

Conclusion will be made from the obtained results along with comparison table’s / charts.

Problem Description for Cooler Tank Die and Methodology

Mound tool is the major segment in plastic component manufacturing. The product cost and quality component by de-pends on the mould structure cost and cooling quality only.Chinese are manufacturing plastic components at very low cost by using low cost mould.In our country we can do the same by reducing mould structure cost and, also quality of the product can be increased by providing sufficient cooling effect.The following process will guide to rectify the problems:• Evaluating existing structures.• Reducing unwanted materials by analyzing at clamping force conditions.• Evaluating and optimizing cooling channel system to provide optimum cooling effect.• By reducing the unwanted materials cost be reduced. • By optimizing cooling channel system, quality will increased by doing reduction of plastic war pages and in-creasing the surface quality of the product.

Review Article- 1401-1402


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a mounting stand for motor. And the final part is bottom tank used to store water.

First, when the evaporative cooler is on, the pump circulates water from the tank of the cooler to the top. It filters down into the pads where some of it is absorbed, but what isn’t absorbed is passed down to the tank of the machine again where it will repeat the cycle of being circulated again to the top. Some of the water will be evaporated from the pads and

the circulating water will eventually be used up. So tank acts as a water reservoir in order to keep the pads damp if the pads ever dry out, the cooler will not be able to cool the air.

We have taken up the parameters of an already pre-pared air cooler and prepared a model for air cooler tank. And that mould tool design is done based on the model, by using CREO 2.0(PRO/ENGINEER) software. After determining the values of the mould tools, manufacturing drawings are prepared with full details selecting the appropriate materials. Sub-sequently, these mould tools are manufactured as per drawing prepared and subjected to quality con-trol tests.

Introduction TO CAD

Computer Aided Design (CAD) is a technique in which man and machine are blended in to prob-lem solving team, intimately coupling the best char-acteristics of each. The result of this combination works better than either man or machine would work alone , and by using a multi discipline ap-proach, it offers the advantages of integrated team work.

Figure 1 Air cooler

MODEL OF AIR COOLER TANK

The above image shows sketch view

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The above image shows Model rare view

The above image shows Final model of cooler tank

2D DRAWINGS OF COOLER TANK

The above image shows 2d drafting views along with dimensions of cooler tank

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MOULD EXTRACTION

A die is usually made in two halves and when closed it forms a cavity similar to the casting desired. One half of the die that remains stationary is known as cover die and the other movable half is called “ejector die”.

The die casting method is used for castings of non-ferrous metals of comparatively Low fusion tem-perature. This process is cheaper and quicker than

permanent or sand mould casting. Most of the au-tomobile parts like fuel pump, carburetor bodies, Horn heater, wipers, brackets, steering wheels, hubs and crank cases are made with this process.

Core: The core which is the male portion of the mold forms the internal shape of the molding.

Cavity:The cavity which is the female portion of the mold, gives the molding its external form.

CAVITY

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The above image shows cavity

CORE

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The above image shows core

Cavity Back Plates- Plates used as a support for the mold cavity block, core block.

DIE DESIGN

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Ejector Plate – Ejector plate is used for pushing ejector pins, retainer plate etc

Ejector Pins - Pins that are pushed into a mold cavity from the rear as the mold opens to force the finished part out of the mold.

The above image is showing ejector plate and ejector pins

The above image is showing ejector pin

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Retainer Plate - The plate on which demountable pieces, such as mold cavities, ejector pins, retainer pins are mounted during molding.

Retainer Pins – Retainer pins are used to push the retainer plate

The above image is showing retainer pin

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Guide Bush Guide Pillar

The above image is showing guide bush and guide pillar

Guide Sleeves

The above image is showing guide bush and guide pillar2D drawings

The above image is showing cavity back plate and retaining plate

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DIE ASSEMBLY

The above image is showing die assembly

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INTRODUCTION TO ANSYS

ANSYS is general-purpose finite element analysis (FEA) software package. Finite Element Analysis is a numerical method of deconstructing a complex system into very small pieces (of user-designated size) called elements. The software implements equations that govern the behaviour of these ele-ments and solves them all; creating a comprehen-sive explanation of how the system acts as a whole. These results then can be presented in tabulated, or graphical forms. This type of analysis is typically used for the design and optimization of a system far too complex to analyze by hand. Systems that may fit into this category are too complex due to their geometry, scale, or governing equations.

ANSYS is the standard FEA teaching tool within the Mechanical Engineering Department at many colleges. ANSYS is also used in Civil and Electrical Engineering, as well as the Physics and Chemistry departments.

MATERIAL PROPERTIES AND BOUNDARY CON-DITIONS

MATERIAL: EN 38

Material Properties: Youngs Modulus (EX) : 20900N/mm2 Poissons Ratio (PRXY) : 0.27 Density :0.000007876kg/mm3Hardness, Brinell 179 - 235 Hardness, Knoop 229 Hardness, Rockwell B 93 Hardness, Rockwell C 15 Hardness, Vickers 217 Bulk Modulus 140 GPa 20300 ksi Typical for steelMachinability 55 % Shear Modulus 80.0 GPa Carbon, C 0.32 - 0.38 % Iron, Fe 97.15 - 98.08 % Manganese, Mn 1.45 - 2.05 % Phosphorous, P <= 0.035 % Silicon, Si 0.15 - 0.35 % Sulfur, S <= 0.040 %

MILD STEEL (MS)

Physical Properties Metric Density 7.87 g/cc Mechanical Properties Metric Hardness, Brinell 126 Hardness, Knoop 145 Hardness, Rockwell B Hardness, Vickers 131 Tensile Strength, Ultimate 440 MPa Tensile Strength, Yield 370 MPa Elongation at Break 15 % 15 %

Reduction of Area 40 % Modulus of Elasticity 205 GPa Bulk Modulus 140 GPa Poissons Ratio 0.29 Machinability 70 % Shear Modulus 80.0 GPa Thermal Properties Metric Specific Heat Capacity 0.486 J/g-°CThermal Conductivity 51.9 W/m-K Component Elements Properties Metric Carbon, C 0.14 - 0.20 % Iron, Fe 98.81 - 99.26 % Manganese, Mn 0.60 - 0.90 % Phosphorous, P <= 0.040 % Sulfur, S <= 0.050 % c22 material propertiesDensity 8.22 g/cc Tensile Strength, Ultimate 765 MPa Tensile Strength, Yield 380 MPa@Strain 0.200 % Modulus of Elasticity 139 GPaBoron, B <= 0.0080 % Carbon, C 0.10 % Chromium, Cr 22 % Cobalt, Co 1.5 % Iron, Fe 18 % Manganese, Mn <= 1.0 % Molybdenum, Mo 9.0 % Nickel, Ni 47 % Silicon, Si <= 1.0 % Tungsten, W 0.60 %

OHNS

Oil Hardened Non-shrinking SteelDensity 7.83 g/cc Modulus of Elasticity214 GPaComponent Elements Properties Metric Carbon, C 0.94 % Chromium, Cr 0.50 % Iron, Fe 96.56 % Manganese, Mn 1.2 % Silicon, Si 0.30 % Tungsten, W 0.50 %

CONSTRAINED AT BOTTOM FORCE ON TOP 741.255 TONS

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STRUCTURAL ANALYSIS OF STANDARD MOULD

The above image is the imported model of composite shaft. Modeling was done in Pro-E and imported with the help of IGES (Initial Graphical Exchanging Specification).

Meshed Model

The above image showing the meshed modal. Default solid Brick element was used to mesh the components. The shown mesh method was called Tetra Hydra Mesh.Meshing is used to deconstruct complex problem into number of small problems based on finite element method.

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The above image is showing the loads applied on a mold

The above image shows the displacement, value is 0.007979mm

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The above image shows the stress, value is 5.61561N/mm2

Structural Analysis of Reduced Thickness


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The above image shows the stress, value is 5.6919N/mm2

Structural Analysis of Reduced Thickness Two


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The above image shows the stress, value is 10.5942N/mm2The above image shows the stress, value is 10.5942N/mm2

Thermal Analysis For Standard Mould

The above image is the imported model of composite shaft. Modeling was done in Pro-E and imported with the help of IGES (Initial Graphical Exchanging Specification).

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The above image showing the meshed modal. Default solid Brick element was used to mesh the components. The shown mesh method was called Tetra Hydra Mesh.Meshing is used to deconstruct complex problem into number of small problems based on finite element method.

The above image shows the melted material temperatureThe above image shows the melted material temperature

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The above image shows the cooling channel temperature

The above images shows the contact area with air

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Results

The above image shows the nodal temperature

The above image shows the thermal gradient

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The above image shows the Thermal flux

Thermal Analysis For Modified Cooling ChannelThermal Analysis For Modified Cooling Channel

Nodal temperature

The above image shows the nodal temperature

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The above image shows the thermal gradient

The above image shows the Thermal flux

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MANUFACTURING PROCESS

By designed the mould tool for air cooler tank, with the parameters now we can manufacture the air cooler tank according to the dimensions. The flow chart of the manufacturing process of the air cooler tank is given below.

Raw material

Hot die steels are most commonly used mould tool materials. they have Excellent toughness, ductility and harden ability .Used for vary large dies espe-cially in thickness greater than 200mm .Also used for hot and warm forging and in extrusion tooling such as intricate dies and also dummy block ,lin-ers, etc.

Surface grinding

After selecting raw material surface grinding is done, Surface Grinding is a widely used process of machining in which a spinning wheel covered in rough particles cuts chips of metallic or non metal-lic substance making them flat or smooth.

Heat treatment

To increase the strength of the material it is heat treated. Heat treatment is an important operation in the manufacturing process of machine parts and tools. Heat Treatment is the controlled heating and cooling of metals to alter their physical and me-

chanical properties without changing the product shape.

Heat Treatment is often associated with increasing the strength of material, but it can also be used to alter certain manufacturability objectives such as improve machining, improve formability, restore ductility after a cold working operation. Thus it is a very enabling manufacturing process that can not only help other manufacturing process, but can also improve product performance by increasing strength or other desirable characteristics.

CNC machining

In modern CNC systems, end-to-end component design is highly automated using CAD/CAM pro-grams. The programs produce a computer file that is interpreted to extract the commands needed to operate a particular machine, and then loaded into the CNC machines for production. Since any par-ticular component might require the use of a num-ber of different tools - drills, saws, etc. - modern machines often combine multiple tools into a sin-gle "cell". In other cases, a number of different ma-chines are used with an external controller and hu-man or robotic operators that move the component from machine to machine. In either case the com-plex series of steps needed to produce any part is highly automated and produces a part that closely matches the original CAD design. After undergoing CNC machining process the mold tool i.e. core and cavity are shown in following figures.

Cavity

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Core

Air cooler tank

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MANUFACTURING PROCESSCORE ROUGHING

CUTTING TOOL

PLAY PATH

VERICUT

ROUGHING PROGRAM

%G71 O0001N0010T1M06S5000M03G00X10.Y-10.G43Z0.H01

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ROUGHING PROGRAM

G71O0001N0010T1M06S5000M03G00X111.616Y-139.396G43Z0.H01G01X111.854Y-140.92Z-1.753F200.X112.545Y-142.3Z-2.34X113.625Y-143.402Z-2.684X114.989Y-144.124Z-2.874X116.508Y-144.395Z-2.94X116.616Y-144.396G03X116.616Y-144.396I0.J5.G02X120.025Y-146.076I0.J-4.3G01X120.153Y-146.242G03X123.68Y-146.474I1.865J1.433X116.616Y-149.396I-7.064J7.078G02X120.228Y-151.363I0.J-4.3G01X120.353Y-151.557G03X123.997Y-152.454I2.298J1.484X116.616Y-154.396I-7.381J13.058G02X120.313Y-156.501I0.J-4.3

CAVITY

ROUGHING

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Displacement in mm

Stress In N/mm2

Standard mold 0.007979 5.61561Reduced thickness 0.008118 5.6919Reduced thickness two

0.008713 10.5942

Structural analysis

Thermal gradient Thermal flux

Nodal temperature

Standard mold 240.348 12.4981 513Modified cooling 260.207 13.5308 513

Thermal analysis

CONCLUSION

• In this project, designed an air cooler water tank as per the parameters; tank capacity is 15 liters, width 380mm, length 420mm, and height 260mm.

• Core and Cavity is extracted for the tank.• Die design is prepared for the same.• The modeling, core-cavity extraction and die

design is done in creo 2.0.• CNC program is generated for core and cavity

to conducting milling operation.• Static and thermal analysis is conducted on

mould structure for weight reduction and for optimized cooling channels.

• As per the analytical results reduction of spacer housing thickness and reduction of core back support is also performing well, so bet-ter to use reduced thick 2 model for cast and weight reduction.

• Optimized location is the better option for ther-mal behavior because of high flux and gradient rates.

BIBLIOGRAPHY

1) Machine design, T.V.Sundararajamoorthy2) Machine design, R.S.Khurmi/J.K.Guptha (S.CHAND)3) Design data book:P.S.G.College of Technology (Kalaikathirachchagam), 4) Www. google.com “online”5) Design of machine element:V.B.Bandari (TATA McGraw-hill6) Injectionmould design: R.G.W. PYE (East-West press Pvt. Ltd

Authors

Choppara. Yasudas

20 Year’s Teching Experience In Govt Polytechnic College

D.Gopichand

Qualification: m.tech Designation: assistant profressor

Experience :4 yr in teaching & 2 yr experience in InfoTech as design engineer

Education

OPTIMIZED DIE STRUCTURE DESIGN OF PLASTIC INJECTION MOULD USING FEM TECHNIQUE