Summary
This experiment investigates injection molding quality. Central composite design for 4-response multi-objective injection molding optimization with custom bounds on all responses.
The design varies 3 factors: melt temp (C), ranging from 200 to 280, injection pressure (MPa), ranging from 50 to 120, and cooling time (s), ranging from 10 to 30. The goal is to optimize 4 responses: surface finish (Ra_um) (maximize), dimensional accuracy (%) (maximize), cycle time (s) (minimize), and warpage (mm) (minimize). Fixed conditions held constant across all runs include mold material = P20_steel, part weight = 45g.
A Central Composite Design (CCD) was selected to fit a full quadratic response surface model, including curvature and interaction effects. With 3 factors this produces 22 runs including center points and axial (star) points that extend beyond the factorial range.
Quadratic response surface models were fitted to capture potential curvature and factor interactions. The RSM contour plots below visualize how pairs of factors jointly affect each response.
Key Findings
For surface finish, the most influential factors were injection pressure (68.6%), cooling time (17.2%), melt temp (14.2%). The best observed value was 1.856 (at melt temp = 200, injection pressure = 120, cooling time = 30).
For dimensional accuracy, the most influential factors were injection pressure (43.6%), melt temp (43.0%), cooling time (13.5%). The best observed value was 99.62 (at melt temp = 240, injection pressure = 148.901, cooling time = 20).
For cycle time, the most influential factors were melt temp (52.9%), injection pressure (26.2%), cooling time (20.9%). The best observed value was 17.8 (at melt temp = 280, injection pressure = 120, cooling time = 10).
For warpage, the most influential factors were melt temp (52.7%), cooling time (25.7%), injection pressure (21.6%). The best observed value was 0.12 (at melt temp = 280, injection pressure = 50, cooling time = 10).
Recommended Next Steps
- Run confirmation experiments at the predicted optimal settings to validate the model.
- Consider whether any fixed factors should be varied in a future study.
Experimental Setup
Factors
| Factor | Low | High | Unit |
melt_temp | 200 | 280 | C |
injection_pressure | 50 | 120 | MPa |
cooling_time | 10 | 30 | s |
Fixed: mold_material = P20_steel, part_weight = 45g
Responses
| Response | Direction | Unit |
surface_finish | ↑ maximize | Ra_um |
dimensional_accuracy | ↑ maximize | % |
cycle_time | ↓ minimize | s |
warpage | ↓ minimize | mm |
Configuration
{
"metadata": {
"name": "Injection Molding Quality",
"description": "Central composite design for 4-response multi-objective injection molding optimization with custom bounds on all responses"
},
"factors": [
{
"name": "melt_temp",
"levels": [
"200",
"280"
],
"type": "continuous",
"unit": "C"
},
{
"name": "injection_pressure",
"levels": [
"50",
"120"
],
"type": "continuous",
"unit": "MPa"
},
{
"name": "cooling_time",
"levels": [
"10",
"30"
],
"type": "continuous",
"unit": "s"
}
],
"fixed_factors": {
"mold_material": "P20_steel",
"part_weight": "45g"
},
"responses": [
{
"name": "surface_finish",
"optimize": "maximize",
"unit": "Ra_um"
},
{
"name": "dimensional_accuracy",
"optimize": "maximize",
"unit": "%"
},
{
"name": "cycle_time",
"optimize": "minimize",
"unit": "s"
},
{
"name": "warpage",
"optimize": "minimize",
"unit": "mm"
}
],
"settings": {
"operation": "central_composite",
"test_script": "use_cases/306_injection_molding/sim.sh"
}
}
Experimental Matrix
The Central Composite Design produces 22 runs. Each row is one experiment with specific factor settings.
| Run | melt_temp | injection_pressure | cooling_time |
| 1 | 240 | 85 | 20 |
| 2 | 280 | 50 | 30 |
| 3 | 200 | 120 | 10 |
| 4 | 240 | 148.901 | 20 |
| 5 | 240 | 85 | 20 |
| 6 | 166.97 | 85 | 20 |
| 7 | 240 | 85 | 1.74258 |
| 8 | 240 | 85 | 20 |
| 9 | 280 | 120 | 10 |
| 10 | 313.03 | 85 | 20 |
| 11 | 240 | 85 | 20 |
| 12 | 240 | 21.099 | 20 |
| 13 | 240 | 85 | 20 |
| 14 | 200 | 50 | 30 |
| 15 | 240 | 85 | 20 |
| 16 | 280 | 50 | 10 |
| 17 | 240 | 85 | 38.2574 |
| 18 | 280 | 120 | 30 |
| 19 | 240 | 85 | 20 |
| 20 | 200 | 50 | 10 |
| 21 | 200 | 120 | 30 |
| 22 | 240 | 85 | 20 |
Step-by-Step Workflow
1
Preview the design
$ doe info --config use_cases/306_injection_molding/config.json
2
Generate the runner script
$ doe generate --config use_cases/306_injection_molding/config.json \
--output use_cases/306_injection_molding/results/run.sh --seed 42
3
Execute the experiments
$ bash use_cases/306_injection_molding/results/run.sh
4
Analyze results
$ doe analyze --config use_cases/306_injection_molding/config.json
5
Get optimization recommendations
$ doe optimize --config use_cases/306_injection_molding/config.json
6
Multi-objective optimization
With 4 competing responses, use --multi to find the best compromise via Derringer–Suich desirability.
$ doe optimize --config use_cases/306_injection_molding/config.json --multi
7
Generate the HTML report
$ doe report --config use_cases/306_injection_molding/config.json \
--output use_cases/306_injection_molding/results/report.html
Features Exercised
| Feature | Value |
| Design type | central_composite |
| Factor types | continuous (all 3) |
| Arg style | double-dash |
| Responses | 4 (surface_finish ↑, dimensional_accuracy ↑, cycle_time ↓, warpage ↓) |
| Total runs | 22 |
Analysis Results
Generated from actual experiment runs using the DOE Helper Tool.
Response: surface_finish
Top factors: injection_pressure (68.6%), cooling_time (17.2%), melt_temp (14.2%).
ANOVA
| Source | DF | SS | MS | F | p-value |
| Source | DF | SS | MS | F | p-value |
| melt_temp | 4 | 0.0977 | 0.0244 | 0.296 | 0.8734 |
| injection_pressure | 4 | 1.0303 | 0.2576 | 3.121 | 0.0720 |
| cooling_time | 4 | 0.1142 | 0.0285 | 0.346 | 0.8405 |
| Lack | of | Fit | 2 | 0.8790 | 0.4395 |
| Pure | Error | 7 | 0.5776 | | |
| Error | 9 | 1.4566 | 0.0825 | | |
| Total | 21 | 2.6987 | 0.1285 | | |
Response: dimensional_accuracy
Top factors: injection_pressure (43.6%), melt_temp (43.0%), cooling_time (13.5%).
ANOVA
| Source | DF | SS | MS | F | p-value |
| Source | DF | SS | MS | F | p-value |
| melt_temp | 4 | 6.5785 | 1.6446 | 2.127 | 0.1596 |
| injection_pressure | 4 | 6.9055 | 1.7264 | 2.232 | 0.1458 |
| cooling_time | 4 | 2.7909 | 0.6977 | 0.902 | 0.5018 |
| Lack | of | Fit | 2 | 2.8380 | 1.4190 |
| Pure | Error | 7 | 5.4136 | | |
| Error | 9 | 8.2516 | 0.7734 | | |
| Total | 21 | 24.5265 | 1.1679 | | |
Response: cycle_time
Top factors: melt_temp (52.9%), injection_pressure (26.2%), cooling_time (20.9%).
ANOVA
| Source | DF | SS | MS | F | p-value |
| Source | DF | SS | MS | F | p-value |
| melt_temp | 4 | 511.4092 | 127.8523 | 3.367 | 0.0603 |
| injection_pressure | 4 | 356.7192 | 89.1798 | 2.348 | 0.1322 |
| cooling_time | 4 | 324.0417 | 81.0104 | 2.133 | 0.1587 |
| Lack | of | Fit | 2 | 350.6357 | 175.3178 |
| Pure | Error | 7 | 265.8200 | | |
| Error | 9 | 616.4557 | 37.9743 | | |
| Total | 21 | 1808.6259 | 86.1250 | | |
Response: warpage
Top factors: melt_temp (52.7%), cooling_time (25.7%), injection_pressure (21.6%).
ANOVA
| Source | DF | SS | MS | F | p-value |
| Source | DF | SS | MS | F | p-value |
| melt_temp | 4 | 0.9057 | 0.2264 | 2.201 | 0.1497 |
| injection_pressure | 4 | 0.5534 | 0.1383 | 1.345 | 0.3258 |
| cooling_time | 4 | 0.7769 | 0.1942 | 1.888 | 0.1968 |
| Lack | of | Fit | 2 | 0.0000 | 0.0000 |
| Pure | Error | 7 | 0.7200 | | |
| Error | 9 | 0.3065 | 0.1029 | | |
| Total | 21 | 2.5425 | 0.1211 | | |
Multi-Objective Optimization
When responses compete, Derringer–Suich desirability finds the best compromise.
Each response is scaled to a 0–1 desirability, then combined via a weighted geometric mean.
Overall Desirability
D = 0.6615
Per-Response Desirability
| Response | Weight | Desirability | Predicted | Dir |
surface_finish |
1.5 |
|
1.71 0.8474 1.71 Ra_um |
↑ |
dimensional_accuracy |
2.0 |
|
99.62 0.9240 99.62 % |
↑ |
cycle_time |
1.0 |
|
52.90 0.1578 52.90 s |
↓ |
warpage |
1.5 |
|
0.21 0.8600 0.21 mm |
↓ |
Recommended Settings
| Factor | Value |
melt_temp | 240 C |
injection_pressure | 85 MPa |
cooling_time | 20 s |
Source: from observed run #17
Trade-off Summary
Sacrifice = how much worse than single-objective best.
| Response | Predicted | Best Observed | Sacrifice |
dimensional_accuracy | 99.62 | 99.62 | +0.00 |
cycle_time | 52.90 | 17.80 | +35.10 |
warpage | 0.21 | 0.12 | +0.09 |
Top 3 Runs by Desirability
| Run | D | Factor Settings |
| #18 | 0.6356 | melt_temp=240, injection_pressure=85, cooling_time=20 |
| #22 | 0.6307 | melt_temp=200, injection_pressure=50, cooling_time=10 |
Model Quality
| Response | R² | Type |
dimensional_accuracy | 0.1482 | linear |
cycle_time | 0.2237 | linear |
warpage | 0.2377 | linear |
Full Multi-Objective Output
============================================================
MULTI-OBJECTIVE OPTIMIZATION
Method: Derringer-Suich Desirability Function
============================================================
Overall desirability: D = 0.6615
Response Weight Desirability Predicted Direction
---------------------------------------------------------------------
surface_finish 1.5 0.8474 1.71 Ra_um ↑
dimensional_accuracy 2.0 0.9240 99.62 % ↑
cycle_time 1.0 0.1578 52.90 s ↓
warpage 1.5 0.8600 0.21 mm ↓
Recommended settings:
melt_temp = 240 C
injection_pressure = 85 MPa
cooling_time = 20 s
(from observed run #17)
Trade-off summary:
surface_finish: 1.71 (best observed: 1.86, sacrifice: +0.15)
dimensional_accuracy: 99.62 (best observed: 99.62, sacrifice: +0.00)
cycle_time: 52.90 (best observed: 17.80, sacrifice: +35.10)
warpage: 0.21 (best observed: 0.12, sacrifice: +0.09)
Model quality:
surface_finish: R² = 0.6617 (quadratic)
dimensional_accuracy: R² = 0.1482 (linear)
cycle_time: R² = 0.2237 (linear)
warpage: R² = 0.2377 (linear)
Top 3 observed runs by overall desirability:
1. Run #17 (D=0.6615): melt_temp=240, injection_pressure=85, cooling_time=20
2. Run #18 (D=0.6356): melt_temp=240, injection_pressure=85, cooling_time=20
3. Run #22 (D=0.6307): melt_temp=200, injection_pressure=50, cooling_time=10
Full Analysis Output
=== Main Effects: surface_finish ===
Factor Effect Std Error % Contribution
--------------------------------------------------------------
injection_pressure 1.1820 0.0764 68.6%
cooling_time 0.2967 0.0764 17.2%
melt_temp 0.2450 0.0764 14.2%
=== ANOVA Table: surface_finish ===
Source DF SS MS F p-value
-----------------------------------------------------------------------------
melt_temp 4 0.0977 0.0244 0.296 0.8734
injection_pressure 4 1.0303 0.2576 3.121 0.0720
cooling_time 4 0.1142 0.0285 0.346 0.8405
Lack of Fit 2 0.8790 0.4395 5.326 0.0393
Pure Error 7 0.5776 0.0825
Error 9 1.4566 0.0825
Total 21 2.6987 0.1285
=== Summary Statistics: surface_finish ===
melt_temp:
Level N Mean Std Min Max
------------------------------------------------------------
166.97 1 1.4800 0.0000 1.4800 1.4800
200 4 1.2833 0.5905 0.4100 1.7100
240 12 1.3832 0.3493 0.6740 1.8560
280 4 1.2508 0.2663 0.8970 1.5360
313.03 1 1.2350 0.0000 1.2350 1.2350
injection_pressure:
Level N Mean Std Min Max
------------------------------------------------------------
120 4 1.4390 0.2050 1.2410 1.7100
148.901 1 1.8560 0.0000 1.8560 1.8560
21.099 1 0.6740 0.0000 0.6740 0.6740
50 4 1.0950 0.5472 0.4100 1.5370
85 12 1.3986 0.2420 0.8320 1.6570
cooling_time:
Level N Mean Std Min Max
------------------------------------------------------------
1.74258 1 1.5430 0.0000 1.5430 1.5430
10 4 1.2463 0.5788 0.4100 1.7100
20 12 1.3563 0.3473 0.6740 1.8560
30 4 1.2877 0.2901 0.8970 1.5370
38.2574 1 1.4940 0.0000 1.4940 1.4940
=== Main Effects: dimensional_accuracy ===
Factor Effect Std Error % Contribution
--------------------------------------------------------------
injection_pressure 2.8400 0.2304 43.6%
melt_temp 2.8000 0.2304 43.0%
cooling_time 0.8775 0.2304 13.5%
=== ANOVA Table: dimensional_accuracy ===
Source DF SS MS F p-value
-----------------------------------------------------------------------------
melt_temp 4 6.5785 1.6446 2.127 0.1596
injection_pressure 4 6.9055 1.7264 2.232 0.1458
cooling_time 4 2.7909 0.6977 0.902 0.5018
Lack of Fit 2 2.8380 1.4190 1.835 0.2287
Pure Error 7 5.4136 0.7734
Error 9 8.2516 0.7734
Total 21 24.5265 1.1679
=== Summary Statistics: dimensional_accuracy ===
melt_temp:
Level N Mean Std Min Max
------------------------------------------------------------
166.97 1 98.1200 0.0000 98.1200 98.1200
200 4 98.0375 1.3876 96.2400 99.6200
240 12 97.3200 0.9730 95.8500 98.8500
280 4 97.5150 0.7653 96.5800 98.2700
313.03 1 95.3200 0.0000 95.3200 95.3200
injection_pressure:
Level N Mean Std Min Max
------------------------------------------------------------
120 4 98.1775 1.2444 96.5800 99.6200
148.901 1 98.8500 0.0000 98.8500 98.8500
21.099 1 96.0100 0.0000 96.0100 96.0100
50 4 97.3750 0.8458 96.2400 98.0500
85 12 97.2017 0.9922 95.3200 98.1900
cooling_time:
Level N Mean Std Min Max
------------------------------------------------------------
1.74258 1 98.0000 0.0000 98.0000 98.0000
10 4 97.6075 1.5408 96.2400 99.6200
20 12 97.1225 1.1235 95.3200 98.8500
30 4 97.9450 0.4931 97.2200 98.2700
38.2574 1 97.8100 0.0000 97.8100 97.8100
=== Main Effects: cycle_time ===
Factor Effect Std Error % Contribution
--------------------------------------------------------------
melt_temp 23.6000 1.9786 52.9%
injection_pressure 11.7000 1.9786 26.2%
cooling_time 9.3167 1.9786 20.9%
=== ANOVA Table: cycle_time ===
Source DF SS MS F p-value
-----------------------------------------------------------------------------
melt_temp 4 511.4092 127.8523 3.367 0.0603
injection_pressure 4 356.7192 89.1798 2.348 0.1322
cooling_time 4 324.0417 81.0104 2.133 0.1587
Lack of Fit 2 350.6357 175.3178 4.617 0.0527
Pure Error 7 265.8200 37.9743
Error 9 616.4557 37.9743
Total 21 1808.6259 86.1250
=== Summary Statistics: cycle_time ===
melt_temp:
Level N Mean Std Min Max
------------------------------------------------------------
166.97 1 35.3000 0.0000 35.3000 35.3000
200 4 41.4000 9.4998 33.6000 52.9000
240 12 33.3417 6.1364 20.0000 42.3000
280 4 37.1750 14.2860 18.1000 49.1000
313.03 1 17.8000 0.0000 17.8000 17.8000
injection_pressure:
Level N Mean Std Min Max
------------------------------------------------------------
120 4 38.4250 15.9151 18.1000 52.9000
148.901 1 42.3000 0.0000 42.3000 42.3000
21.099 1 30.6000 0.0000 30.6000 30.6000
50 4 40.1500 7.1389 33.6000 47.1000
85 12 31.6917 7.0010 17.8000 38.9000
cooling_time:
Level N Mean Std Min Max
------------------------------------------------------------
1.74258 1 38.4000 0.0000 38.4000 38.4000
10 4 37.7250 15.1319 18.1000 52.9000
20 12 31.5333 7.2951 17.8000 42.3000
30 4 40.8500 8.4113 33.6000 49.1000
38.2574 1 36.4000 0.0000 36.4000 36.4000
=== Main Effects: warpage ===
Factor Effect Std Error % Contribution
--------------------------------------------------------------
melt_temp 0.9278 0.0742 52.7%
cooling_time 0.4520 0.0742 25.7%
injection_pressure 0.3805 0.0742 21.6%
=== ANOVA Table: warpage ===
Source DF SS MS F p-value
-----------------------------------------------------------------------------
melt_temp 4 0.9057 0.2264 2.201 0.1497
injection_pressure 4 0.5534 0.1383 1.345 0.3258
cooling_time 4 0.7769 0.1942 1.888 0.1968
Lack of Fit 2 0.0000 0.0000 0.000 1.0000
Pure Error 7 0.7200 0.1029
Error 9 0.3065 0.1029
Total 21 2.5425 0.1211
=== Summary Statistics: warpage ===
melt_temp:
Level N Mean Std Min Max
------------------------------------------------------------
166.97 1 0.7250 0.0000 0.7250 0.7250
200 4 0.5052 0.2187 0.2100 0.6760
240 12 0.8472 0.2821 0.5180 1.5000
280 4 0.6012 0.4539 0.1200 1.1940
313.03 1 1.4330 0.0000 1.4330 1.4330
injection_pressure:
Level N Mean Std Min Max
------------------------------------------------------------
120 4 0.5475 0.4928 0.1200 1.1940
148.901 1 0.8010 0.0000 0.8010 0.8010
21.099 1 0.9280 0.0000 0.9280 0.9280
50 4 0.5590 0.1306 0.4250 0.6760
85 12 0.8829 0.3316 0.5180 1.5000
cooling_time:
Level N Mean Std Min Max
------------------------------------------------------------
1.74258 1 0.5180 0.0000 0.5180 0.5180
10 4 0.6348 0.4170 0.2100 1.1940
20 12 0.9238 0.3073 0.6350 1.5000
30 4 0.4718 0.2616 0.1200 0.6760
38.2574 1 0.7210 0.0000 0.7210 0.7210
Optimization Recommendations
=== Optimization: surface_finish ===
Direction: maximize
Best observed run: #18
melt_temp = 200
injection_pressure = 120
cooling_time = 30
Value: 1.856
RSM Model (linear, R² = 0.0307, Adj R² = -0.1308):
Coefficients:
intercept +1.3386
melt_temp -0.0271
injection_pressure +0.0434
cooling_time -0.0551
RSM Model (quadratic, R² = 0.2831, Adj R² = -0.2546):
Coefficients:
intercept +1.3282
melt_temp -0.0271
injection_pressure +0.0434
cooling_time -0.0551
melt_temp*injection_pressure -0.2756
melt_temp*cooling_time -0.0226
injection_pressure*cooling_time -0.0181
melt_temp^2 -0.0389
injection_pressure^2 +0.0302
cooling_time^2 +0.0242
Curvature analysis:
melt_temp coef=-0.0389 negligible curvature
injection_pressure coef=+0.0302 negligible curvature
cooling_time coef=+0.0242 negligible curvature
Predicted optimum (from linear model, at observed points):
melt_temp = 200
injection_pressure = 120
cooling_time = 10
Predicted value: 1.4642
Surface optimum (via L-BFGS-B, linear model):
melt_temp = 200
injection_pressure = 120
cooling_time = 10
Predicted value: 1.4642
Model quality: Weak fit — consider adding center points or using a different design.
Factor importance:
1. melt_temp (effect: 0.5, contribution: 38.0%)
2. injection_pressure (effect: 0.4, contribution: 34.4%)
3. cooling_time (effect: 0.4, contribution: 27.6%)
=== Optimization: dimensional_accuracy ===
Direction: maximize
Best observed run: #17
melt_temp = 240
injection_pressure = 148.901
cooling_time = 20
Value: 99.62
RSM Model (linear, R² = 0.0437, Adj R² = -0.1157):
Coefficients:
intercept +97.4314
melt_temp -0.0559
injection_pressure +0.2598
cooling_time -0.0487
RSM Model (quadratic, R² = 0.4725, Adj R² = 0.0769):
Coefficients:
intercept +97.2024
melt_temp -0.0559
injection_pressure +0.2598
cooling_time -0.0487
melt_temp*injection_pressure -0.9575
melt_temp*cooling_time +0.1900
injection_pressure*cooling_time +0.4725
melt_temp^2 +0.0005
injection_pressure^2 +0.1880
cooling_time^2 +0.1550
Curvature analysis:
injection_pressure coef=+0.1880 convex (has a minimum)
cooling_time coef=+0.1550 convex (has a minimum)
melt_temp coef=+0.0005 negligible curvature
Notable interactions:
melt_temp*injection_pressure coef=-0.9575 (antagonistic)
injection_pressure*cooling_time coef=+0.4725 (synergistic)
Predicted optimum (from quadratic model, at observed points):
melt_temp = 200
injection_pressure = 120
cooling_time = 30
Predicted value: 99.0528
Surface optimum (via L-BFGS-B, quadratic model):
melt_temp = 200
injection_pressure = 120
cooling_time = 30
Predicted value: 99.0528
Model quality: Weak fit — consider adding center points or using a different design.
Factor importance:
1. injection_pressure (effect: 3.0, contribution: 60.6%)
2. melt_temp (effect: 1.1, contribution: 22.9%)
3. cooling_time (effect: 0.8, contribution: 16.5%)
=== Optimization: cycle_time ===
Direction: minimize
Best observed run: #16
melt_temp = 280
injection_pressure = 120
cooling_time = 10
Value: 17.8
RSM Model (linear, R² = 0.1291, Adj R² = -0.0160):
Coefficients:
intercept +34.8864
melt_temp +0.0643
injection_pressure +3.9024
cooling_time +0.8303
RSM Model (quadratic, R² = 0.4390, Adj R² = 0.0183):
Coefficients:
intercept +33.1798
melt_temp +0.0643
injection_pressure +3.9024
cooling_time +0.8303
melt_temp*injection_pressure -4.2625
melt_temp*cooling_time +1.8875
injection_pressure*cooling_time +6.5375
melt_temp^2 +0.3683
injection_pressure^2 +1.0733
cooling_time^2 +1.1183
Curvature analysis:
cooling_time coef=+1.1183 convex (has a minimum)
injection_pressure coef=+1.0733 convex (has a minimum)
melt_temp coef=+0.3683 convex (has a minimum)
Notable interactions:
injection_pressure*cooling_time coef=+6.5375 (synergistic)
melt_temp*injection_pressure coef=-4.2625 (antagonistic)
melt_temp*cooling_time coef=+1.8875 (synergistic)
Predicted optimum (from quadratic model, at observed points):
melt_temp = 200
injection_pressure = 120
cooling_time = 30
Predicted value: 49.3206
Surface optimum (via L-BFGS-B, quadratic model):
melt_temp = 200
injection_pressure = 50
cooling_time = 30
Predicted value: 19.9157
Model quality: Weak fit — consider adding center points or using a different design.
Factor importance:
1. injection_pressure (effect: 34.8, contribution: 79.8%)
2. cooling_time (effect: 4.7, contribution: 10.7%)
3. melt_temp (effect: 4.2, contribution: 9.6%)
=== Optimization: warpage ===
Direction: minimize
Best observed run: #21
melt_temp = 280
injection_pressure = 50
cooling_time = 10
Value: 0.12
RSM Model (linear, R² = 0.0236, Adj R² = -0.1391):
Coefficients:
intercept +0.7614
melt_temp -0.0084
injection_pressure -0.0633
cooling_time -0.0040
RSM Model (quadratic, R² = 0.3091, Adj R² = -0.2091):
Coefficients:
intercept +0.8792
melt_temp -0.0084
injection_pressure -0.0633
cooling_time -0.0040
melt_temp*injection_pressure +0.1705
melt_temp*cooling_time -0.1032
injection_pressure*cooling_time -0.1690
melt_temp^2 -0.0692
injection_pressure^2 -0.0552
cooling_time^2 -0.0524
Curvature analysis:
melt_temp coef=-0.0692 negligible curvature
injection_pressure coef=-0.0552 negligible curvature
cooling_time coef=-0.0524 negligible curvature
Predicted optimum (from linear model, at observed points):
melt_temp = 240
injection_pressure = 21.099
cooling_time = 20
Predicted value: 0.8769
Surface optimum (via L-BFGS-B, linear model):
melt_temp = 280
injection_pressure = 120
cooling_time = 30
Predicted value: 0.6856
Model quality: Weak fit — consider adding center points or using a different design.
Factor importance:
1. injection_pressure (effect: 1.0, contribution: 76.4%)
2. melt_temp (effect: 0.2, contribution: 14.5%)
3. cooling_time (effect: 0.1, contribution: 9.1%)