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11InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
ExperimentalExperimental andand SimulativeSimulative ResultsResultsofof NeckingNecking OperationOperation
on Aluminium Canon Aluminium Can
ByBy
R. FrattiniR. Frattini
(Frattini S.p.A., Seriate, Italy)(Frattini S.p.A., Seriate, Italy)
A.A.AttanasioAttanasio, C., C. ContriContri, E. Ceretti, C., E. Ceretti, C. GiardiniGiardini
((DipartimentoDipartimentodidi IngegneriaIngegneriaMeccanicaMeccanica, Universit, Universit deglidegliStudiStudidi Brescia, Italy)di Brescia, Italy)
Thursday, September 23, 2004Thursday, September 23, 2004
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22InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
1. Frattini S.p.A.2. Production.3. Necking Operation.4. Objectives.5. The FE Model6. FE Model Validation:
I. Evaluation of m.II. Thickness comparison.III. Can height comparison.IV. Axial force.
7. Conclusion.8. Future work.
OutlineOutlineOutline
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33InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
Frattinis history began more than 80 years ago, in 1920, whenthe 4 Frattini brothers started on a machinery business inBergamo.The third generation (1994) takes its managing responsibilitiescontinuing the companys traditional philosophy which is radically
oriented to customers service & technology.
1. Frattini S.p.A.1.1. Frattini S.p.A.Frattini S.p.A.
[Frattini S.p.A.]
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44InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
Frattini S.p.A. is a world wide leader company in the field ofmachines for deformation of aluminium monobloc containers
through ironing and necking machineries.
2. Production2.2. ProductionProduction
[Frattini S.p.A.]
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55InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
Necking is a cold forming process in which the open end of ashell or tubular component is closed by axial pressing with a
shaped die.Necking is obtained by multistage mechanic presses.
[Altan et al., 1983]
3. Necking Operation3.3. Necking OperationNecking Operation
[Frattini S.p.A.]
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66InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
The analyzed necking operation, object of this research, isobtained by a Frattini S.p.A. machine with 26 necking dies.
3. Necking Operation3.3. Necking OperationNecking Operation
[Frattini S.p.A.]
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77InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
This research is a cooperation between Frattini S.p.A. and the
Technology and Manufacturing System Group of the University ofBrescia with the aim of:
Determining the process parameters used in the FE Analysisfor the necking of a D&I aluminum can.
Comparing experimental and simulative results in order tovalidate the FE model (on the basis of geometrical and forceparameters).
Optimizing the necking process according to the simulativeresults (to improve the product quality and decrease the totalnumber of steps).Using the FE code to design new neck profiles.
4. Objectives4.4. ObjectivesObjectives
U i i di B i Di i di I i M i
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88InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
Because of the can symmetry
the FE Analysis has beenconducted using the axisymmetricgeometry type available in theimplicit commercial code DEFORM2D.
Die and can geometries
together with the processparameters have been providedby Frattini S.p.A.
ClampingClamping GripGrip
Aluminium CanAluminium Can
NeckingNecking DieDie
5. FE Model5.5. FE ModelFE Model
U i it di B iU i it di B i Di ti t di I i M iDi ti t di I i M i
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99InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
The initial can height is 194.8 mm, the outside diameter is 53 mmand the wall thickness is 0.22 mm.
To obtain the final neck profile 26 necking steps are necessary.
Can
Necking Die
5. FE Model5.5. FE ModelFE Model
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1010InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
The material of the can is Al3004 and its characterization has beendone in a previous research made with Brescia University.
5. FE Model5.5. FE ModelFE Model
70,000 [MPa]E
2.8*10-6 [cm3/kg]
0.0547n389.14 [MPa]K
290 [MPa]y
s= 389.14e0.0547
0
50100
150
200
250300
350
400
450
0 0,01 0,02 0,03 0,04 0,05
[MPa]
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1111InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
The validation of the FE Model is necessary for the further processoptimization.In order to reach this goal the following experimental andsimulative parameters have been evaluated and compared:
Can Wall Thickness.Can Height.Axial Force.
The validation has been carried out changing the friction factor mwhich represents the lubrication conditions at the die can interface.
6. FE Model Validation6.6. FE Model ValidationFE Model Validation
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1212InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
In fact, the first problem to solve to simulate the actual neckingprocess was the evaluation of the friction factor (m) by means ofseveral simulations run with different m values.
The can wall thickness and the can height comparison betweenthe simulation results and the experiments allowed thedetermination of the correct m value.
6. FE Model Validation6.6. FE Model ValidationFE Model Validation
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1313InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
Wall thickness comparison with different m values
0,2200,2220,2240,2260,2280,2300,2320,2340,2360,2380,2400,2420,244
0,2460,2480,250
1 2 3 4 5 6
# Necking Die
Wallthickness[mm]
From Experiments
m=0,001
m=0,0025
m=0,005
m=0,0075
There is a good agreement between experimental wall thickness
values and simulative ones when m is equal to 0.005.
6. FE Model Validation6.6. FE Model ValidationFE Model Validation
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1414InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
Wall Thickness Comparison (1)
0,200
0,2250,250
0,275
0,300
0,325
0,350
0,375
1 6 11 16 21 26
# Necking Die
Wall
Thickness[m
m]
From Simulation
From Experiments
Up to the necking die #18 simulation results match very well with
the simulative ones.
6.II Wall Thickness Comparison6.II6.II Wall Thickness ComparisonWall Thickness Comparison
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p g gp g g
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1515InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
Wall Thickness Comparison (2)
-4
-2
0
2
4
6
8
10
12
1 6 11 16 21 26
# Necking Die
%Sim.-Exp.Wall
T
hickness
After the necking die #18, the % difference between simulativeand experimental thicknesses increases. This may be due to anexcessive thickening of the top of the necked can.
6.II Wall Thickness Comparison6.II6.II Wall Thickness ComparisonWall Thickness Comparison
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1616InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
Analyzing the actual productive process it was found that the cantop is cut four times (after the necking dies #6, #12, #18 and#22).A new simulative campaign has been performed introducing in
the model the cut of the can top edge.The so obtained simulative results match very well with theexperimental ones.
6.II Wall Thickness Comparison6.II6.II Wall Thickness ComparisonWall Thickness Comparison
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Wall Thickness Comparison (3)
0,2
0,225
0,25
0,275
0,3
0,325
0,35
0,375
1 6 11 16 21 26
# Necking Die
WallThickness[
mm] From Experiments
From Simulation
In the picture the very good agreement between simulation andexperiment is shown in terms of can wall thickness.
6.II Wall Thickness Comparison6.II6.II Wall Thickness ComparisonWall Thickness Comparison
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Can Height Comparison
180
190
200
210
220
1 6 11 16 21 26# Necking Die
Canheight[mm]
From Experiments
From Simulation
The picture shows the same good agreement in terms of canheight.
The cut of the can edge is highlighted by the red circles.
6.III Can Height Comparison6.III6.III Can Height ComparisonCan Height Comparison
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T l i Si i d i L i
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1919InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
Unless the axial force is different for each necking die, it ispossible to define a common force profile with a maximum initial
value followed by a lower average one.
Axial Force (Necking Die #6, m=0.005)
0
200400
600
800
1000
1200
0 10 20 30 40
Necking Die Displacement [mm]
Axia
lForce[N]
Maximum Force
Average Force
6.IV Axial Force6.IV6.IV Axial ForceAxial Force
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2020InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
Analyzing the overall FE force results it is possible to see anincrease in the force after the necking die # 19.
Axial Force
0
600
1200
1800
2400
3000
1 6 11 16 21 26
# Necking Die
Ax
ialForce[N]
Maximum Force
Average Force
6.IV Axial Force6.IV6.IV Axial ForceAxial Force
19
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6.IV Axial Force6.IV6.IV Axial ForceAxial Force
The force increase may be due to:
An incorrect material model (the material work hardening istoo high).
A can mesh with insufficient density (few elements in thethickness dimension).
A too simplified process modelling (the internal part of thenecking die in the actual process is moving so the frictionconditions are different).
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7. Conclusion7.7. ConclusionConclusion
To increase the model reliability an
additional experimental campaignis in progress measuring for eachstep:
The can wall thickness.
The can height.
The axial force.
[Frattini S.p.A.]
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2323InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
The performed simulations of the necking process provide a good
picture of the actual process in terms of can wall thickness andgeometry.
It was necessary to introduce, in the simulation, the cut of the
can top edge to avoid excessive increase of the can thickness andof the necking force.
To be able to use the FE results to reduce & optimize the numberof necking steps it is necessary to improve the model reliability interms of axial force previsions.
7. Conclusion7.7. ConclusionConclusion
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2424InternationalInternational ConferenceConference INNOVATIONS IN METAL FORMING (23INNOVATIONS IN METAL FORMING (23--2424 SeptemberSeptember20042004 BresciaBrescia -- Italy)Italy)
To reduce & optimize the numberof dies necessary for the necking
operation considering the FEsuggestions.To increase the product quality
and simulate new neck profiles.In this way new operations couldbe done by the Frattini machinesuch as:
Full Shaping body.Hydroforming.
8. Future Work 8.8. Future WorkFuture Work
[Frattini S.p.A.]