menelaos pappas1, john kechagias1, vassilis iakovakis1 ... roughness modelling an… · 28 –30...
TRANSCRIPT
28 – 30 January 2011 Rome, Italy
Menelaos Pappas1, John Kechagias1, Vassilis Iakovakis1, Stergios Maropoulos2
1 Department of Mechanical Engineering, Technological Educational Institute of Larissa, Larissa 41110, Greece
[email protected] , [email protected] , [email protected] Department of Mechanical Engineering, Technological Educational Institute of Western Macedonia, Kozani 50100, Greece
Levels
Parameters 1 2 3
A Core diameter (%) 48 50 -
B Flute angle (o) 38 45 50
C Rake angle (o) 18 20 22
D Relief angle 1st (o) 20 22 25
E Relief angle 2nd (o) 25 28 30
F Cutting depth (mm) 0.5 1.0 1.5
G Cutting speed (rpm) 5000 6000 7000
H Feed (mm/flute) 0.05 0.08 0.10
No.Columns
Performance Measures
A B C D E F G H Ra Ry Rz
1 48 38 18 20 25 0.5 5000 0.05 0.08 0.93 0.73
2 48 38 20 22 28 1.0 6000 0.08 0.17 1.27 1.17
3 48 38 22 25 30 1.5 7000 0.10 0.18 1.30 1.07
4 48 45 18 20 28 1.0 7000 0.10 1.66 5.73 6.83
5 48 45 20 22 30 1.5 5000 0.05 0.12 1.47 0.90
6 48 45 22 25 25 0.5 6000 0.08 0.19 2.10 1.13
7 48 50 18 22 25 1.5 6000 0.10 0.22 1.80 1.27
8 48 50 20 25 28 0.5 7000 0.05 1.33 12.13 7.10
9 48 50 22 20 30 1.0 5000 0.08 0.19 1.27 1.27
10 50 38 18 25 30 1.0 6000 0.05 0.13 1.20 0.93
11 50 38 20 20 25 1.5 7000 0.08 0.19 1.47 1.23
12 50 38 22 22 28 0.5 5000 0.10 0.17 1.27 1.10
13 50 45 18 22 30 0.5 7000 0.08 0.11 1.03 1.10
14 50 45 20 25 25 1.0 5000 0.10 0.13 1.27 1.03
15 50 45 22 20 28 1.5 6000 0.05 0.14 0.77 0.70
16 50 50 18 25 28 1.5 5000 0.08 0.22 1.37 1.10
17 50 50 20 20 30 0.5 6000 0.10 0.15 1.20 0.97
18 50 50 22 22 25 1.0 7000 0.05 0.16 1.37 0.90
Scope
A Neural Network (NN) modelling approach for the prediction of surface texture parameters during end milling of aluminium alloy 5083.
Approach
18 carbide end mill cutters were manufactured with a five axis grinding machine assigned to mill eighteen pockets having different combinations of geometry parameters and cutting parameter values, according to the L18 (21x37) standard orthogonal array.
A feed-forward back-propagation NN was developed using data obtained from experimental work conducted on a CNC milling machine center according to the principles of Taguchi’s design of experiments.
Conclusion
It was found that NN approach can be applied easily on designed experiments and predictions can be achieved, fast and quite accurately.
Experimental Setup
Each of the 18 end mill cutters cut a pocket of 100 x 64 x 15 mm on the two faces of an Al 5083 plate of 500 x 280 x 60 mm.
Different cutting parameter values were used for each pocket.
The surface texture parameters measured were the arithmetical mean roughness (Ra), maximum peak (Ry) and 10-point mean roughness (Rz).
Surface roughness measurements were taken using a RUGOserf tester.
Each surface roughness parameter (Ra, Ry, and Rz) was measured three times, parallel to the arrows, and an average of each was calculated for each of the eighteen pockets .
Modelling Framework
An Artificial Neural Network developed to predict the surface roughness parameters during end milling on the surface texture of Al alloy 5083
Input Parameters: Core diameter, Flute angle, Rake angle, 1st and 2nd Relief angle 2nd, Cutting depth, Cutting speed, Feed
Output Parameters: Arithmetical mean roughness (Ra), maximum peak (Ry), 10-point mean roughness (Rz)
Model Architecture: Feed-Forward with Back-Propagation learning (8-7-5-4-3)
Modelling Data Sets: Training data: 50% (9 samples) , Validation data: 20% (4 samples), Testing data: 30% (5 samples)
Surface roughness measurements
Core diameter
Flute angle
Rake angle
Relief angle 1st
Relief angle 2nd
Cutting depth
Cutting speed
Feed
Ra
Ry
Rz
Modelling Results
Response surface diagram of Ry in relation to the cutting speed and feed, with a cutting depth of 1,5 mm
Conclusions – Future Work
A FFBP-NN model was built to estimate the surface roughness indicator response according to the geometry and cutting parameters of the process.
The performance of the network was found to be efficient providing very good correlation between output and target during training (R=1), validation (R=0.89) and testing procedure (R=0.93).
The response surface diagram shows that when the geometry parameters take their optimum values, the increase of cutting speed, as well as the decrease of feed rate, results in improvement of the surface roughness, which is also in accordance with the machining theory.
Multi-parameter investigation of the process according to other quality indicators will be studied and analyzed in future work.
Ry
(μm
)
Parameters levelsParameter design according to L18 (21x37)
orthogonal array and performance measures
3rd International Conference on Agents and Artificial Intelligence