Zu Hanser-Fachbuch.de
Warenkorb
Gary F. Schiller
A Practical Approach to Scientific Molding
Preface
7
About the Author
9
Contents
11
1 Injection Unit: Screw
17
1.1 Prepares the Melt
17
1.2 Flows the Melt
18
1.3 Pressurizes the Melt
19
1.4 Sections of the Screw
19
1.4.1 Feed Zone
19
1.4.2 Transition or Compression Zone
20
1.4.3 Metering Zone
20
1.5 L/D or Length/Diameter
20
1.6 Compression Ratio
20
1.7 Profile
22
1.8 Injection Pressure
22
1.9 Injection High Limit Fill Time
23
1.10 Injection Pack Pressure/Time
23
1.11 Injection Hold Pressure/Time
23
1.12 Non-return Valve Function
24
1.13 Different Styles of Non-return Valves
25
1.14 Decompression/Pull Back/Suck Back
26
1.15 Screw Rotate Delay
26
1.16 Mixing Head on a Reciprocating Screw
27
1.17 Barrier Screws
27
2 Injection Unit: Barrel
29
2.1 Barrel
29
2.2 Thermocouples
30
2.3 Heater Bands
33
2.4 Spacing of Heater Bands
35
2.5 Wattage
35
2.6 Worn Barrel
36
2.7 Feed Throat
37
2.8 Venting of the Barrel
37
2.9 Hopper
38
2.10 Hopper Dryer Diagram
39
2.11 Filter Packs/Dispersion Disks/Screen Packs
40
3 Clamping Unit
43
3.1 Hydraulic
43
3.2 Toggle
44
3.3 Weakness
44
3.4 Tie-Bar-Less
44
3.5 Single Point
45
3.6 Platen Wrap
46
3.7 Mold Coverage Area
47
3.8 Cleanliness of the Platens
47
3.9 Care of Bolt Holes
48
3.10 Proper Bolt Location
49
3.11 Weight of Mold Calculations
50
3.12 Mold Height
51
3.13 Calculating Clamp Tonnage for a Press
51
4 Ejectors/Controllers, Human Machine Interface (HMI)
53
4.1 Ejector Pattern and Spacing
53
4.2 Ejector Spacing
53
4.3 Controllers
56
4.3.1 Open Loop
56
4.3.2 Closed Loop
56
4.4 Key Pads
57
5 Machine Performance Testing
59
5.1 Rear Barrel Zone Optimization
59
5.2 Load Sensitivity
60
5.2.1 Purge Disk
61
5.3 Pressure Response
62
5.4 Dynamic Non-return Valve Test (FILL)
64
5.5 Static Non-return Valve Test (PACK/HOLD)
65
5.6 Injection Speed Linearity
66
6 Process Development Test
69
6.1 Tonnage Calculation/Projected Area
69
6.2 On Machine Rheology Curve (Viscosity Curve) or Fill Time Study
72
6.3 Construction of Viscosity Curve Graph
73
6.4 Least Pressure Curve
76
6.5 Plastic Flow Rate (Qp)
76
6.6 Shear Rates
76
6.7 Gate Freeze, Gate Seal, or Gate Stabilization
80
6.8 Runner Weight Study
83
6.9 Range Finding for Gate Seal
84
6.10 Manifold Imbalance and Balance of Fill Analysis
84
6.11 Cooling Optimization Study
86
6.12 Pressure Loss Study
87
7 Plastic Temperature
89
7.1 Molecular Structure of Common Materials
89
7.2 Morphology
90
7.2.1 Amorphous Resin Morphology
90
7.2.2 Semi-Crystalline Resin Morphology
90
7.3 Glass Transition Temperature (Tg)
91
7.4 Melt Transition Temperature (Tm)
91
7.5 Shrinkage
92
7.5.1 Isotropic Shrinkage
92
7.5.2 Anisotropic Shrinkage
93
7.6 Melt Density versus Solid Density
94
7.7 Advantages/Disadvantages of Hot Runner versus Cold Runner
95
7.8 Induced Shear through a Hot or Cold Runner System
96
8 Plastic Flow
97
8.1 Fountain Flow
97
8.2 Flow of Plastic
98
8.3 How to Calculate Flow Rate (Qp)
98
8.4 Calculating Volume of Shot Size
99
8.5 Blocking a Cavity
100
8.6 Flow through a Mold
101
8.7 Orientation
101
8.8 Transfer/Cut-Off Position
102
8.9 Viscosity Changes
102
8.10 Intensifying Ratio (Ri)
103
8.11 Pressure Limited Process
104
8.12 Safe Start-Up Shot Size
105
8.13 Runner Sizing
107
9 Plastic Pressure (Pack/Hold)
109
9.1 Plastic Pressure
109
9.2 Dynamic versus Static
109
9.3 Viscosity Changes
109
9.4 End of Cavity Pressure Loss
110
9.5 Part Shrinkage versus Cavity Pressure
110
9.6 Maximum Average Pressure at Parting Line before Flashing
111
10 Cooling
115
10.1 Plastic Cooling
115
10.2 Turbulent versus Laminar Flow
115
10.3 Reynolds Number
117
10.4 Water Lines
118
10.5 Area of Water Line
119
10.6 Series/Parallel
119
10.7 Cooling Rate
121
10.8 Ineffective Cooling
122
10.9 Cooling Time
122
10.10 Depth, Diameter, and Pitch
122
10.11 Baffles/Bubblers
124
10.12 How a Thermolator/Mold Heater Works
124
11 Benchmarking the Injection Molding Process
127
12 Process Troubleshooting
131
12.1 Black Specks
131
12.2 Blush
133
12.3 Brittleness
134
12.4 Burns
135
12.5 Burns in Gates
137
12.6 Cloudy Parts
137
12.7 Color Streaks
138
12.8 Deformation: Ejector Pin Marks
139
12.9 Degraded Polymer
140
12.10 Design
140
12.11 Fish Hooks
141
12.12 Flash
142
12.13 Flow Lines
144
12.14 Hot Tip Drool
145
12.15 Jetting
146
12.16 Long Gates
147
12.17 Nozzle Drool
149
12.18 Parts Sticking in Mold
149
12.19 Pulls
150
12.20 Shorts/Non-Fills
150
12.21 Sinks
151
12.22 Splay
153
12.23 Sprue Sticking
154
12.24 Surface Imperfections
155
12.25 Voids
156
12.26 Warpage
157
12.27 Weld Lines
159
13 What is Important on a Set-Up Sheet?
161
14 Commonly Used Conversion Factors and Formulas
165
14.1 Conversion Factors
165
14.2 Common Formulas for Injection Molding
166
15 Machine Set-Up
169
16 Things That Hurt the Bottom Line of a Company
173
17 Terms and Definitions
175
18 Reference List for Further Courses and Reading
189
18.1 Courses
189
18.2 Reading
189
Index
191
Leere Seite
2
© 2009-2024 ciando GmbH