Review Article

Directed Energy Deposition via Artificial Intelligence-Enabled Approaches

Table 10

Comparison between various network models used.

Algorithm usedDepth, layer sizes, training time, and testing timeDatasetAccuracyVariation from experimental valueRef.

ANN1 hidden layer, 7 neurons 3-7-1, feed-forward, backpropagation neural network modelNot mentioned.98.7%67.9% MAPE[94]
CNN(i) Avg pooling layer
(ii) Convolution layer (3 × 3; 32 filters)
(iii) Avg pooling layer
(iv) Convolution layer (3 × 3; 16 filters)
(v) Flattening layer
(vi) Fully connected layer
(vii) Softwax function (confidence values into probabilities)
The time-series thermal images were collected with the help of the cameras and other multiple DED process settings.80%Not mentioned[57]
RNN(i) 1–5 layers
(ii) 100–500 GRU units
(iii) 1–3 fully connected layers
Self-made using GAMMA.MSE: 2.97e − 5 after 100 epochsNot mentioned[58]
LSTM(i) Input layer
(ii) LSTM layer
(iii) Fully connected layer
(iv) Dropout layer
(v) Fully connected layer
(vi) Regression layer
FEM sim data and data from artificial crack experiments.The average absolute error of prediction: 2.0 μm(i) Abs error for FEM data: 6.88 μm
(ii) Avg error for artificial crack data: 7.41 μm.
[59]
ANN: feed-forward backpropagationInput parameters: L0 orthogonal array
Input variables: 3
Self-prepared, pre-processed, and labeled data97.08% R-squaredNot mentioned[60]
CNN2 convolution layers:
(i) Layer 1: 10 filters of kernel size 6 × 6;
(ii) Layer 2: 20 filters of kernel size 4 × 4 max-pooled with pool size of 2 × 2 convolution (20 × 7 × 7) images ⟶ max-pooling ⟶ fully connected layer (with 200 nodes) ⟶ activation function RELU ⟶ 50% dropout
100,000 images of both classes. Training images: 60,00096.02%: case one
93.69%: case two
24%: case one
9.6%: case two
[63]
Stacked RNN(i) 1–5 hidden layers
(ii) 100–500 GRU units
(iii) 1–3 fully connected layers
Training time: 40 h on Nvidia Quadro P5000
Built using GAMMA.MSE: 3.17e − 5N/A[58]
ANNSingle hidden layer (3-16-4)Trained dataset using ANN backpropagation.90%5%[64]
Neural network (I), gradient boosted decision tree (II), SVM (III), and Gaussian process (IV)(I) For regression: linear neurons = 283, non-linear = 210, learning rate: 0.000871
For classification: linear neurons = 358, non-linear = 744, LR = 0.000465; 1 hidden layer. (IV) LR = 0.01; max depth = 20
Previously unpublished experimental results of this author. Input set (powder material, substrate material, spot size, power, Mass flow rate, travel velocity)II > IV > III > I ensemble regression accuracy of 70.5% and an ensemble classification accuracy of 72.3%Not mentioned[66]
Hybrid of ANN and genetic algorithm approachNot mentionedExperimentally measured process variables.84%5%[65]
ANNNeural networks with hidden layer containing nodes in the following orders were tested: 3-1-3, 3-3-3, 3-6-3, 3-7-3, 3-1-1-3, 3-3-3-3, 3-6-6-3, 3-7-7-3Prepared after conducting 60 experiments. Constraints like availability of material, cost, and time required for experiment were considered82%2%[69]
ANN1-5-10-150 groups of data were gathered from the experiment.Not mentioned4%[70]