simulation of deep drawing die for optimized die radius using fem technique

60

International Journal of Research and Innovation (IJRI)


SIMULATION OF DEEP DRAWING DIE FOR OPTIMIZED DIE RADIUS USING FEM TECHNIQUE

G.Bhargav*, K.Durga

1.Research Scholar, Department of Mechanical Engineering,Vikas college of Engineering and Technology,Nunna, Vijayawada rural, Krishna (DIST),Andhrapradesh,India.2.Assistant Professor, Department of Mechanical Engineering, Vikas college of Engineering and Technology,Nunna, Vijayawada rural, Krishna (DIST),Andhrapradesh,India.

*Corresponding Author:

G.Bhargav , Research Scholar, Department of Mechanical Engineering,Vikas college of Engineering and Technology,Nunna, Vijayawada ru-ral, Krishna (DIST),Andhrapradesh,India.

Published: December 16, 2014Review Type: peer reviewedVolume: I, Issue : IV

Citation: G.Bhargav Research Scholar, (2014) SIMULA-TION OF DEEP DRAWING DIE FOR OPTIMIZED DIE RA-DIUS USING FEM TECHNIQUE

Introduction To Sheet Metal

Method of Analysis

In general, the complexity of these processes and the great number of factors involved in them mak-ing very difficult to select the parameter values properly.

Then, different analytical, numerical and experi-mental methods are being developed in order to analyze the best combination of them. Now-a-days analytical methods still continue being studied and developed in spite of numerical methods allow ob-

taining solutions with high precision and detail ev-els in the analysis of this type of process.

Finite element method has been used as well in sev-eral studies about metal forming processes recently. The main objective of this paper presented in it is the multi stage deep drawing analysis. According to John Monaghon et al, as the die radius is reduced, this increases the amount of force required to draw the material. The increased force on the punch and the greater difficulty in getting the material around the die radius causes stretching marks on the cup wall and an uneven thickness distribution. To ver-ify the above experimental results and to validate the simulation done, several simulations were per-formed by varying the die radius. Furthermore, the effect of the above process parameters on the form-ability and quality issues are studied.The stamping of thin metallic sheets is a widely used industrial material forming process. It allows production of thin walled parts with complicated shapes such as automotive panels or structural parts. The process consists of the plastic deforma-tion of an initial at blank subjected to the action of a rigid punch and die while constrained on the periphery by a blank holder.

Abstract

Deep drawing process is one of the most used Metal Forming Process within the industrial field. Different analytical, numerical, empirical and experimental methods have been developed in order to analyze it. This work reports on the initial stages of finite element analysis (FEA) of a Deep drawing process.

The objective of this study is to determine theinfluencingof die radius in drawing process and analyzing the process by varying the Die radius and keeping the Friction, and Blank Thickness as constant.

In this paper Punch and blank thicknessissame;die with various geometries (with various corner radius) were drawn by using PRO/Engineer software. And an effort is made to study the simulation effect of main process variant namely die radius using finite element analysis.

• Initially literature survey will be done to describe about deep drawing process and effect of die radius in press tools.

• FEA models will be generated using PRO/Engineer.

• Structuralanalysis will be carried out to determine the structural characteristics with the change of corner radius.

• Structural analysis will be carried to find the actual effect of radius in process and also to find limiting radius value for the same.

• Transient analysis will be carried to find the actual effect of radius in process and also to find limiting radius value for the same with the variation of time period.

1401-1402

61


The main variables involved in this type of process are:• Die Radius• Friction• Punch Radius• Blank Thickness.

These factors determine the maximum punch load in drawing, the sheet-thickness variation after drawing, and the maximum limit drawing ratio. If the height ofthe work piece in industrial production is too high, multi-redrawing is necessary in order to obtain a successful product.

The finite element method has recently been suf-ficiently developed for the analysis of metal form-ing processes. Hence, much research has been performed using the finite element method. The purpose of this study is to clarify the mechanics of ductile fracture in bulk metal forming processes.

The following four kinds of ductile fracture crite-ria, that is to say, freudenthal’s fracture criterion, Cockcroft and latham’s fracture criterion, Brozzo et al.’s fracture criterion and oyane’s fracture crite-rion are used. These four kinds of ductile fracture criteria are used in the analysis of deep drawing. The analytical results of the work using Cockcroft and latham’s fracture criterion and using Brozzo et al.’s fracture criterion agree satisfactorily with the experimental result.

Sheet metal

Sheet metal is metal formed by an industrial pro-cess into thin, flat pieces. It is one of the funda-mental forms used in metalworking and it can be cut and bent into a variety of shapes. Countless everyday objects are constructed with sheet metal. Thicknesses can vary significantly; extremely thin thicknesses are considered foil or leaf, and pieces thicker than 6 mm (0.25 in) are considered plate.Sheet metal is available in flat pieces or coiled strips. The coils are formed by running a continuous sheet of metal through a roll slitter.The thickness of sheet metal is commonly specified by a traditional, non-linear measure known as its gauge. The larger the gauge number, the thinner the metal. Commonly used steel sheet metal ranges from 30 gauge to about 8 gauge. Gauge differs be-tween ferrous (iron based) metals and nonferrous metals such as aluminum or copper; copper thick-ness, for example are measured in ounces (and rep-resent the thickness of 1 ounce of copper rolled out to an area of 1 square foot).There are many different metals that can be made into sheet metal, such as aluminum, brass, cop-per, steel, tin, nickel and titanium. For decorative uses, important sheet metals include silver, gold, and platinum (platinum sheet metal is also utilized as a catalyst.) Sheet metal is used for car bodies, airplane wings, medical tables, roofs for buildings (architecture) and many other applications. Sheet metal of iron

and other materials with high magnetic permeabil-ity, also known as laminated steel cores, has ap-plications in transformers and electric machines. Historically, an important use of sheet metal was in plate armor worn by cavalry, and sheet metal con-tinues to have many decorative uses, including in horse. Sheet metal workers are also known as "tin bashers" (or "tin knockers"), a name derived from the hammering of panel seams when installing tin roofs.Material used for sheet metal process

Stainless steel

Usage of steel as a building material is popular as a cost effective, quality material as compared to the alternatives. The three most common stainless steel grades available in sheet metal are 304, 316, and 410.

Grade 304 is the most common of the three grades. It offers good corrosion resistance while maintain-ing formability and weldability. Available finishes are #2B, #3, and #4. Grade 303 is not available in sheet form

Grade 316 possesses more corrosion resistance and strength at elevated temperatures than 304. It is commonly used for pumps, valves, chemical equip-ment, and marine applications. Available finishes are #2B, #3, and #4

Grade 410 is a heat treatable stainless steel, but it has a lower corrosion resistance than the other grades. It is commonly used in cutlery. The only available finish is dull.

Aluminium

Aluminium is also a popular metal used in sheet metal due to its flexibility, wide range of options, cost effectiveness, and other properties.[4] The four most common aluminium grades available as sheet metal are 1100-H14, 3003-H14, 5052-H32, and 6061-T6.Grade 1100-H14 is commercially pure aluminium, highly chemical and weather resistant. It is ductile enough for deep drawing and weldable, but has low strength. It is commonly used in chemical process-ing equipment, light reflectors, and jewelry.Grade 3003-H14 is stronger than 1100, while main-taining the same formability and low cost. It is cor-rosion resistant and weldable. It is often used in stampings, spun and drawn parts, boxes, cabinets, tanks, and fan blades

Grade 5052-H32 is much stronger than 3003 while still maintaining good formability. It maintains high corrosion resistance and weldability. Common ap-plications include electronic chassis, tanks, and pressure vesselsGrade 6061-T6 is a common heat-treated structural aluminium alloy. It is weldable, corrosion resistant, and stronger than 5052, but not as formable. It los-

62


es some of its strength when welded.[3] It is used in modern aircraft structures.

Part Modeling In Pro/Engineer

The above image is showing final part of cavity

The above image is showing final part of core

Above Figure

A) Cavity hole which creates outer impression of component.

B) Chamfer is used to reduce the errors of guide pillar relocation.

C) Guide holes are used to place the guide pillar in running pro-cess.

D)Guide slots are used to place the clamps for fixing.

Above FigureA) Corner radius is preferred for punching and drawing to pre-vent damage to the sheet it effects operation speed and quality.

B)Core (or) male part is used to make inner impression on object and dia is depends on the same.

C)Core supporting plate is connected with top booster it includes

core part.

Guide pillars are used to guide the core to assemble in desired location in process.

A) Top booster is placed on cavity plate to prevent direct interaction with power press hammerB)Counter head and hole is used to assemble the top booster to the core.

63


Draw tool calculations

Input: punch height = 100mmPunch diameter = 20mmThickness = 1mmCup diameter = 22mm

Calculations of blank diameter:

1.In case of cup → the blank is circular 2.Area of blank is

(D0²п)/4 = (d0²п)/4 + d1пh

Do =√(d12+ 4d1h)

Do = √(202+ 4×20×100) = 91.65mm

Blank piece diameter = 91.65mmLimiting Drawing Ratio(LDR): B = (Do/dn)

DO = diameter of blankdn= smallest diameter (cup diameter)Draw ratio in general:

Bi= (d¡)/(d¡+1)B = 91.65/22= 4.615

First drawing B1= 3.9 to 3.0

Redraw Bi = 3.0 to 1.0 (for copper, aluminum and mild steel)

Draw force:

Fd max = n× π ×d ×t ×UTSd = Diameter of cupt = thicknessUTS = Ultimate Tensile Strengthn = Drawing coefficient (0.7 to 0.95) Fd max=0.7× 3.14×22 ×1×162 = 7833.672 MPa

Analysis of cup drawing:

Cup to be drawnDiameter = 91.65Height = 100mm DO =√(dn2+ 4 dn hn) = √(91.652+4×91.65×100) = 212.27mm

Calculations of drawing ratio:

4 stages of deep drawing is preferred for 100 (or) below height’s 1st draw -3.818 to 32nddraw - 3 to 23rddraw - 2 to 14thdraw -1 to 0

Results

No .of opera-tions

Height in mm Diameter in mm

Drawing ratio

0 blank ____ _____ 91.65 ____ _____

1st draw 25 74.7365 0.95

2nddraw 50 57.824 1.9

3rddraw 75 40.91 2.86

4thdraw 100 24 3.818

Equivalent strain

Strain in the direction of 3 axisφ= φ2=91.65 ;φ2 = φw = 91.65 ; φ3= φth = 1

Equivalent strain:

φe = √2 / 3√((φ1-φ2)²+(φ2-φ3)²+(φ1-φ3)²) = √2 / 3 √((91.65-91.65)²+(91.65-1)²+(91.65-1)²) =√2 / 3 √((0)+(90.65)²+(90.65)²) = 0.47 √(8217.4+8217.4) = 0.47 √16434.8 = 60.253

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.

64


Boundary conditions:

Constrained at thickness direction for cup analysis.Constrained cavity area for die analysis.Force= 7833.672 MPa

Structural Analysis Of Draw Tool With 4 Raidus (Stainless Steel Sheet)

The above image is the imported model of draw tool. Modeling was done in Pro-E and imported with the help of IGES (Initial Graphical Exchanging Specifi-cation).

Meshed Model

The above image shows the meshed modal. Default solid Brick element was used to mesh the compo-nents. The shown mesh method was called Tetra Hydra Mesh.

Meshing is used to deconstruct complex problem into number of small problems based on finite ele-ment method

The above image shows the loads applied

Solution

Solution – Solve – Current LS – ok

Post Processor

General Post Processor – Plot Results – Contour Plot - Nodal Solution – DOF Solution – Displacement Vector Sum

The above image shows displacement value 0.00726 mm

The above image shows von-misses stress value 12.365 N/mm2

Structural Analysis Of Draw Tool Die With 4 Rai-dus (Stainless Steel And Tool Steel)

The above image is the imported model of draw tool die with 4mm radius. Modeling was done in Pro-E and imported with the help of IGES (Initial Graphi-cal Exchanging Specification).

65


Meshed Model

The above image showing the meshed modal. De-fault solid Brick element was used to mesh the com-ponents. The shown mesh method was called Tetra Hydra Mesh.

Meshing is used to deconstruct complex problem into number of small problems based on finite ele-ment method

Post Processor

General Post Processor – Plot Results – Contour Plot - Nodal Solution – DOF Solution – Displacement Vector Sum

The above image shows displacement value 4.29347 mmGeneral Post Processor – Plot Results – Contour Plot – Nodal Solution – Stress – Von Mises Stress


Transient Analysis Of Draw Tool Die With 4 Radius (Stain-less Steel And Tool Steel)


General Post Processor – Plot Results – Contour Plot – Nodal Solution – Stress – Von Mises Stress



General Post Processor – Plot Results – Contour Plot – Nodal So-lution – Stress – Von Mises Stress


66


The above image shows strain value 0.025091

The above image shows von-misses stress graph

Results Table

Cup

4 radius 5 radius 6 radius 7raidus 8 radius

Dis-place-mentIn mm

0.00072 0.00095 0.00073 0.00153 0.00190

Stress In N/mm2

12.365 16.1762 7.57467 19.7477 34.3424

Draw tool die


Dis-place-mentIn mm

4.29347 8.065 10.7043 19.3959 16.7185

Stress In N/mm2

7258.09 7841.36 8515.06 11323.8 9811.01

Draw tool die transient


Dis-place-mentIn mm

.3 .91 1.48 1.34 1.72

Stress In N/mm2

2114 3076 3814 4326 3954

Strain .025 .017 .025 .028 .022

Graphs

For Part

For die part

67


For die transient analysis

Conclusion

The objective of this project work is to present effect of radius in deep drawing process and to suggest the optimum value of radius, for presenting the re-quired values following process is done using FEM technique.

• Literature survey and data collection is done to understand the deep drawing process, require-ment’s and effects of radius.• General models and FEA models are prepared for further study.• Structural analysis is carried out on component and die structure by varying the corner radius val-ues of 4,5,6,7 and 8• Transient analysis is carried out to determine the values of punch deformation and stress, also to de-termine stresses developing on sheet.• Graphs are created for better understanding of re-sults.

As per the analytical results this work concludes as below.

1) Corner radius mainly effects on process speed and required force.2) Increment of corner radius up to certain limit im-proves production rate quality.3) As per the cup and die analysis results 7 radius is the better option.4) 8 radius die performance is comparatively low than 7 radiuses die.5) 7 radius die is providing maximum force on sheet to become sheet into desired cup shape.

References

1) KopanathiGowtham, K.V.N.S. Srikanth & K.L.N. Murty2) Yuung-ming HUANG, Shiao-cheng LU3) R.UDAY KUMAR4) G. Venkateswarlu, M. J. Davidson and G. R. N. Tagore 5) Y. N. Dhulugade1, P. N. Gore2

Authour

G.Bhargav*

Research Scholar, Department of Mechanical Engineering,Vikas college of Engineering and Technology,Nunna, Vijayawada rural, Krishna (DIST),Andhrapradesh,India.

K.Durga

Assistant Professor, Department of Mechanical Engineering, Vi-kas college of Engineering and Technology,Nunna, Vijayawada rural, Krishna (DIST),Andhrapradesh,India.

simulation of deep drawing die for optimized die radius using fem technique

Education