Today's IS machines have reached speeds of 800 bottles/min, requiring faster and smoother lehr stacker operation. As well as the increased production speeds, glass container designers have also been creative in reducing glass weights and optimising shapes, not always in favour of the glass manufacturer. Slimmer and taller glass bottle designs have raised the point of gravity and therefore, reduced stability. Coping with such demands has meant not only designing for a higher number of stacking cycles but also for a perfectly smooth stacking motion in all three movements (forward, backward and lift). Optimising the return of stroke of the stacker bar was just one aim. Whereas actual demand in the past decade stood at 12-15 cycles/min, it has risen occasionally to 18 cycles/min and will certainly increase in the future. To accommodate increasing production speeds, Pennekamp has further developed and upgraded its three axis stacker, as explained in this article.
