EFFECTS OF EXTRUSION BLOW MOLDING INTERNAL COOLING ...

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The increasing demand for plastic bottles has forced bottle suppliers to gear up for the higher outputs required to meet customer demand. The steps taken to increase output include installing more equipment, retrofitting existing equipment, or replacing existing machinery with new state-of-the-art equipment. According to a survey by the Packaging Machinery Manufacturer’s Institute (PMMI), 55.2 percent of respondents reported replacing existing machinery with new models rated for higher output, while 39 percent reported upgrading their existing equipment with state-of-the-art retrofit kits (PMMI, 2003). The first quarter of 2003 saw $21.8 million in blow molding machinery sales (SPI, 2003). Total sales for blow molding machinery in all industries in 2003 are estimated at $505 million compared to around $350 million for 1999 (Rosato et. al., 2004). 1.2 Extrusion Blow Molding 1.2.1 Process The extrusion blow molding industry has been on the rise since its first successful commercially produced item, the “Stopette” deodorant squeeze bottle by Plax Corporation, in 1945. After this success, nearly every major company who made rubber machines and injection machines began to develop blow molders. Material limitations of the time made only small container blow molding possible (Belcher, 1999). High Density Polyethylene, made available in 1956, led to the success of low cost, reliable extrusion blow molded manufacturing in North America and allowed for the production of larger containers (Lee, 1990). 2
The process of extrusion blow molding was developed from modifications made to early injection molders as well as glass container machines. Extrusion blow molding machines use the following process (Figure 2): • Plastic pellets of a specific material are fed into the extruder to be melted • Melted plastic is extruded into a tube called a parison and introduced into the mold chamber • An aluminum mold with a cavity in the shape of the desired bottle is clamped around the parison clamping the bottom shut; the parison is then cut off at the top • A blow pin drops into the neck opening of the bottle • Plastic is mechanically forced into the “finish” of the bottle by the blow pin tip forming the threads and mouth of the container • The blow pin (Figure 3) blows air into the tube, inflating the plastic tube like a balloon • The tube is inflated into the walls of the mold cavity • The mold cavity is water-cooled; when plastic comes in contact with the mold, the plastic cools and becomes hard • The mold opens, the bottle flash is removed, and then the cooled and formed bottle is dropped onto a conveyor to proceed to a packing or filling operation 3
Page 1 and 2: EFFECTS OF EXTRUSION BLOW MOLDING I
Page 3 and 4: Copyright by Kirk Alan Valko 2004
Page 5 and 6: TABLE OF CONTENTS LIST OF TABLES ..
Page 7 and 8: LIST OF TABLES Table 1. Fasti Cost
Page 9 and 10: Figure 24. Assembly Drawing........
Page 11: 1 - INTRODUCTION AND LITERATURE REV
Page 15 and 16: and dropped onto the conveyor, the
Page 17 and 18: Internal cooling is the process of
Page 19 and 20: pin is entering the bottle finish.
Page 21 and 22: 1.3.3 Costs Total cost of the unit
Page 23 and 24: Figure 7. Machine Surround Before F
Page 25 and 26: Table 2. Effect of Decreased Crysta
Page 27 and 28: 1.4.2 Wall thickness In addition to
Page 29 and 30: 2 - EXPERIMENTAL DESIGN AND TEST ME
Page 31 and 32: to determine the connection between
Page 33 and 34: 2.2 Experimental Methods 2.2.1 Samp
Page 35 and 36: Average temperature, checked by the
Page 37 and 38: Table 5. Bottle Body Dimension Tole
Page 39 and 40: D 2659, 1995). Twenty samples from
Page 41 and 42: Figure 15. Compression Data Example
Page 43 and 44: Figure 16. DSC Sample Pan Crimper T
Page 45 and 46: 3 - DATA AND RESULTS 3.1 Cycle time
Page 47 and 48: Table 7. Dimensional Test Result Co
Page 49 and 50: 3.3 Compression Strength Compressio
Page 51 and 52: Table 10. Percent Crystallinity of
Page 53 and 54: Table 12. Percent Crystallinity at
Page 55 and 56: wall thickness. Compression strengt
Page 57 and 58: performance tests. It would be desi
Page 59 and 60: 5.8 Optical Microscopy Optical micr
Page 61 and 62: 51 APPENDIX A Dimensional Results T
Page 63 and 64:
53 Table 15. Dimensional Test Resul
Page 65 and 66:
Figure 18. Conventional Wall Thickn
Page 67 and 68:
Figure 22. Fasti Wall Thickness 2 0
Page 69 and 70:
Table 18. Compression Test Results
Page 71 and 72:
Bekum Blow Molder Operating Instruc
Page 73 and 74:
a) “SP1”(set point one) tempera
Page 75 and 76:
i) Only one function may be used at
Page 77 and 78:
) Use Screwdriver to turn catch abo
Page 79 and 80:
Figure 25. Detail 01 - Adaptor 69
Page 81 and 82:
Figure 27. Detail 03 - Cooling Slee
Page 83 and 84:
Figure 29. Detail 05 - Tip 73
Page 85 and 86:
APPENDIX E Fasti Setup Experiment E
Page 87 and 88:
Data Analysis Figures 31, 32, and 3
Page 89 and 90:
Figure 31. Main Effects Plot for Fa
Page 91 and 92:
BIBLIOGRAPHY ASTM Standard D2463-95
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