THE ROLE OF THE

More documents

Recommendations

Info

Manufacturing and Process Technology 73 Mold Heater Polymer sheet Mold FIgure 5.5 Vacuum-forming diagram. Vacuum • In blow molding, the end of a piece of polymer that was initially formed by an extrusion process is scaled by the closing of the mold. Compressed air is passed into the tube and expanded to fit the mold. • Vacuum forming (shown in Figure 5.5) is the reverse of blow molding. A sheet of heated material is placed over a mold and the air is sucked from the mold [5]. The plastic is drawn down to conform to the shape of the part, such as a gas tank. Gas tanks comprise several different polymers and are blow molded as sheets. Parts are allowed to cool before being released from the mold. • Calendering is a process in which a preheated polymer mix is turned into a continuous sheet by being passed through two heated rolls, which squeeze the material to a programmed thickness [5]. A recent development in injection molding is in-mold assembly (IMA). This process is very useful for instrument panel air registers in the HVAC and interior areas. Over 70% of IP air registers have what is known as a dual vane construction—the ability to direct air in two directions. For these applications, a slider knob to control the airflow is necessary as well as dual colors for high-end vehicles. If an IP register can be molded in color as well as assembled in the mold, a cost savings will be realized by eliminating the assembly process as well as a painting operation or coating process. Basically, in the process all components are molded in parallel within one cycle, and the components are moveable. A tool configuration for IMA is shown in Figure 5.6. In IMA, different types of materials can be injected into a single tool that rotates. For instance, a polyamide material can be injected into injection port 1; injection area 2 can be PBT or some other compound and injection port 3 can be a third material (a different polyamide, perhaps). Cycle times for this process are typically in line with regular injection molding; however, a savings in time is realized because a complete part is ejected from the machine.
74 The Role of the Chemist in Automotive Design 5.4 alumInum ProcessIng Aluminum processing is very important in automotive applications due to its light weight and versatility. One of the areas where a chemist’s knowledge is used is in heat exchanger technology (i.e., radiators, condensers, heater cores, charge air coolers, and evaporator cores). Aluminum alloys are utilized here because of their lower density, corrosion resistance, and high thermal conductivity. Typically, three layers of aluminum are used in a brazing process. Most often the layers consist of variations of the aluminum association materials listed in Table 5.4 as well as a third layer consisting of nearly all aluminum with modifications to promote corrosion resistance. In this type of system, silicon is leached out by manganese in the 3003 layer, leaving a corrosion-resistant third layer. The process described is critical, especially with automobile condenser production. In the case of condensers, the tubes used to carry high-pressure refrigerant need to be extruded. These extruded tubes need to be brazed in order to maintain the structural integrity of the thin design (100 µm). table 5.4 typical Heat exchanger material designations Standard layer alloy Part 1 Direction of rotation Injection1 Material 1 FIgure 5.6 In-mold assembly diagram. Injection 3 Material 3 Part 3 Injection 2 Material 2 Part 2 designation si Fe cu mn zn al 3003
Page 2:
THE ROLE OF THE CHEMIST IN AUTOMOTI
Page 5 and 6:
CRC Press Taylor & Francis Group 60
Page 8 and 9:
Contents Preface...................
Page 10 and 11:
Contents ix 6.6 Thermal Properties
Page 12:
Contents xi 11.4 Glass Microspheres
Page 16:
The Author Herman Phlegm was born i
Page 19 and 20:
2 The Role of the Chemist in Automo
Page 21 and 22:
Page 23 and 24:
Page 25 and 26:
Page 27 and 28:
10 The Role of the Chemist in Autom
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40: 22 The Role of the Chemist in Autom
Page 48 and 49: 3 3.1 IntroductIon Component Materi
Page 50 and 51: Component Materials in Automobiles
Page 60: Component Materials in Automobiles
Page 89: 72 The Role of the Chemist in Autom
Page 98 and 99: 6 6.1 IntroductIon Engineering Poly
Page 100 and 101: Engineering and Structural Polymers
Page 110: Engineering and Structural Polymers
Page 117 and 118: 100 The Role of the Chemist in Auto
Page 128 and 129: 8 8.1 IntroductIon Seal and Gasket
Page 130 and 131: Seal and Gasket Design 113 table 8.
Page 132 and 133: Seal and Gasket Design 115 The main
Page 134 and 135: Seal and Gasket Design 117 Properti
Page 136 and 137: Seal and Gasket Design 119 table 8.
Page 138 and 139: Seal and Gasket Design 121 within t
Page 140 and 141:
Seal and Gasket Design 123 F F F F
Page 142 and 143:
Seal and Gasket Design 125 R R O ma
Page 144 and 145:
Seal and Gasket Design 127 stabiliz
Page 146 and 147:
9 9.1 IntroductIon HVAC System Over
Page 148 and 149:
HVAC System Overview and Refrigeran
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166:
Page 169 and 170:
152 The Role of the Chemist in Auto
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
190 Index Carbon dioxide emissions,
Page 209 and 210:
192 Index heat exchanger designatio
Page 211 and 212:
194 Index Power train, 95 Power tra
show all

THE ROLE OF THE

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?