When a glowing molten glass mass enters the mould at the Ardagh Glassworks in Neuenhagen, a highly dynamic process begins, which decides the quality of the final product. Dimensional accuracy, wall thickness distribution and surface quality must be exactly right and precisely formed and stabilised within a few seconds. To improve the process, Ardagh has therefore installed a modular vacuum concept from Busch Vacuum Solutions.
Glaswerk Neuenhagen is part of the internationally active Ardagh Group, a supplier of packaging solutions focusing on glass containers. The requirements for process safety and repeatability are therefore high. Vacuum plays a role here not only as a supply variable but as a process-relevant control parameter that must be precisely adapted to the respective conditions.
The vacuum supply was dimensioned in collaboration with Busch Vacuum Solutions specifically for the requirements of glass forming. During the forming process, the vacuum is used to control the venting of the mould chambers, which, in combination with the internal overpressure, defines the boundary conditions for uniform material distribution and stable forming of the container geometry.
A new vacuum solution
A new vacuum concept based on screw vacuum technology with Cobra NC vacuum pumps has been implemented together with Ardagh. This technology operates dry and contactless, eliminating the need for operating fluids in the compression chamber. The vacuum pumps are equipped with frequency converters that allow for continuous adjustment of the motor speed. This enables the volumetric capacity of the pumps to be adapted to process conditions, which reduces mechanical stress and minimises thermal load.
Vacuum is therefore no longer considered a static supply variable, but is used as an actively regulated process variable. The integrated pressure measurement continuously records the current vacuum level, and the control loops keep it stable by adjusting the motor speed. This ensures that the vacuum level remains constant even under changing operating conditions.
Live results
The new vacuum concept allows vacuum conditions in the moulding process to be reliably set and maintained throughout the entire cycle. This leads to more uniform wall thicknesses, reduced quality-relevant deviations, and minimised adjustments during operation. Energy consumption is significantly reduced, as vacuum pumps no longer need to operate continuously at maximum power.
Source: Busch Vacuum Solutions
