PETpla.net Insider 11 / 2018

BOTTLE MAKING 16 PET planet Insider Vol. 19 No. 11/18 www.petpla.net Both Sidel and Krones use stand- ard clamping devices with both mould sides opening. KHS has moved to one stationary and one moving side, reducing blow-wheel footprint. Sipa uses what they call the “crocodile” mould movement, with one side being stationary while the other opens to the front instead of to the side (Fig. 4.17). It is also a space-saving measure. Figure 4.17 Instead of opening side- ways, this clamp opens one side verti- cally. Picture courtesy of Sipa. Changeover times Changeover times are important for those factories that do not have the luxury of running the same prod- uct 365 days/year but have to change 2–5 times per week. When the same necks are used, the steps involved are as follows:  Disconnect water hoses  Replace blow moulds  Replace bottom inserts  Replace stretch rod stops or dial in new stop values  Change PLC recipe  Change preform supply. All blow machine manufacturers have now quick-change systems (Fig. 4.18 that make this task much less time consuming.  Water hoses are equipped with quick-disconnects or eliminate the disconnection completely by feeding water through the carriers with the molds being outfitted with O-rings that do not require anything to be disconnected.  Blow moulds used are mounted with two screws holding each half. Modern systems feature lock- ing mechanisms that allow mould removal with one twist of a special tool or no tool at all.  Same for the bottom inserts.  Stretch rod stops are also easily replaced or not necessary when servomotors are used instead of cam-driven pneumatic cylinders. An overview of the various parameters of rotary machines Parameter KHS Krones Sidel Sipa Max. b/c per h (small water) 2,250 2,250 2,300 2,250 Max. bottle size (l) 3 3.5 3.5 3 Cavitation 0.7 l max. 4–36 8–36 6–34 6–24 Maximum transfer ring 36/48 38/48 38/48.5 38/43 Preform orientation Up Up Down/up Down/up Stretch rod movement Servo Electromagnetic Cam/air Cam/air Max. output (b/h) 81,000 81,000 78,200 50,400 Table 4.4 Depending on the machine speed different degrees of machine rotation take different times Bottles per cavities per hour Degrees 1500 1600 1700 1800 1900 2000 2100 2200 15 0.100 0.094 0.088 0.083 0.079 0.075 0.071 0.068 30 0.200 0.188 0.176 0.167 0.158 0.150 0.143 0.136 45 0.300 0.281 0.265 0.250 0.237 0.225 0.214 0.205 60 0.400 0.375 0.353 0.333 0.316 0.300 0.286 0.273 75 0.500 0.469 0.441 0.417 0.395 0.375 0.357 0.341 90 0.600 0.563 0.529 0.500 0.474 0.450 0.429 0.409 105 0.700 0.656 0.618 0.583 0.553 0.525 0.500 0.477 120 0.800 0.750 0.706 0.667 0.632 0.600 0.571 0.545 135 0.900 0.844 0.794 0.750 0.711 0.675 0.643 0.614 150 1.000 0.938 0.882 0.833 0.789 0.750 0.714 0.682 165 1.100 1.031 0.971 0.917 0.868 0.825 0.786 0.750 180 1.200 1.125 1.059 1.000 0.947 0.900 0.857 0.818 195 1.300 1.219 1.147 1.083 1.026 0.975 0.929 0.886 210 1.400 1.313 1.235 1.167 1.105 1.050 1.000 0.955 225 1.500 1.406 1.324 1.250 1.184 1.125 1.071 1.023 240 1.600 1.500 1.412 1.333 1.263 1.200 1.143 1.091 255 1.700 1.594 1.500 1.417 1.342 1.275 1.214 1.159 270 1.800 1.688 1.588 1.500 1.421 1.350 1.286 1.227 285 1.900 1.781 1.676 1.583 1.500 1.425 1.357 1.295 300 2.000 1.875 1.765 1.667 1.579 1.500 1.429 1.364 315 2.100 1.969 1.853 1.750 1.658 1.575 1.500 1.432 330 2.200 2.063 1.941 1.833 1.737 1.650 1.571 1.500 345 2.300 2.156 2.029 1.917 1.816 1.725 1.643 1.568 360 2.400 2.250 2.118 2.000 1.895 1.800 1.714 1.636 Table 4.3 Depending on the speed of the machine the same time leads to different angle displacements Time (s) Bottles per cavities per hour (degree) 1500 1600 1700 1800 1900 2000 2100 2200 0.1 15 16 17 18 19 20 21 22 0.15 22.5 24 25.5 27 28.5 30 31.5 33 0.2 30 32 34 36 38 40 42 44 0.25 37.5 40 42.5 45 47.5 50 52.5 55 0.3 45 48 51 54 57 60 63 66 0.35 52.5 56 59.5 63 66.5 70 73.5 77 0.4 60 64 68 72 76 80 84 88 0.45 67.5 72 76.5 81 85.5 90 94.5 99 0.5 75 80 85 90 95 100 105 110 0.55 82.5 88 93.5 99 104.5 110 115.5 121 0.6 90 96 102 108 114 120 126 132 0.65 97.5 104 110.5 117 123.5 130 136.5 143 0.7 105 112 119 126 133 140 147 154 0.75 112.5 120 127.5 135 142.5 150 157.5 165 0.8 120 128 136 144 152 160 168 176 0.85 127.5 136 144.5 153 161.5 170 178.5 187 0.9 135 144 153 162 171 180 189 198 0.95 142.5 152 161.5 171 180.5 190 199.5 209 1 150 160 170 180 190 200 210 220 Table 4.2