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Progress and change in machine concepts 1995 – 2010
Looking fifteen years back, those were the characteristics of a typical packaging machine: The favored drive solution was a three-phase current drive, preferrably with frequency converter for speed adjustment. Drives were few, servo drives even fewer. The control usually came as PLC sequence control, and movements were carried out via cam discs, pneumatic actors, or one main shaft. The machines had keys and buttons for a very limited number of functions. If displays were incorporated at all, they could only indicate one line of plain text.
Fifteen years later, the machines are equipped with decentralized servo drives, highly integrated motion controls with high performance processors, and operator surfaces in graphical design. The result is a striking increasing of cycle numbers. The following overview shows the figures of progress, while also taking into consideration the increased resource consumption:
- Output + 100%
- Noise level - 50%
- Weight + 339%
- Format changeover time - 50%
- Machine footprint + 175%
- Assembly time / machine cycle + 350%
- Energy consumption / machine cycle + 275%
- Costs / machine cycle -10% (-34%)
It is a remarkable aspect of this 15-year comparison that output has doubled, whereas costs per machine stroke have simultaneously dropped by 10%. Taking into consideration a 2.5% annual rate of price increase, the price per machine cycle has even decreased by 34%. But this did not make the machines lighter. Despite servo technology and fewer ‘active’ mechanical elements, today’s machines have tripled in weight, due to added control cabinets, coverings, and sophisticated safety technology and noise protection.
The number of drives has multiplied by more than six, not only because of the decentralized drives: Format changeover times were reduced by half, requiring additional drive technology and automation. With all these complex technologies, assembly times multiplied, with much of this increased effort going into electronics. Fifteen years ago, 70% of all assembly work was dedicated to mechanical tasks. Today, the work required for the assembly of electronic components has risen to nearly 50%.
At the same time, the operation of today’s machinery consumes more energy per machine cycle: At double the machine speed, the energy consumption has nearly tripled. Pneumatic movements were replaced by servo movements, and cycle operation requires much acceleration and deceleration energy that demands its toll despite the energy recovery devices of modern lines.
The mains tester was replaced by the laptop. This upgrade also exemplifies the changed requirements of staff qualification. The software sector in particular demands qualifications that were not even known 15 years ago, with requirements increasing in parallel to automation degree.
Strikingly, there is a new trend towards very simple machines, in particular in Emerging Markets. The medium output range seems to die out. The future will show if this trend persists with a leap from ‘very simple’ to ‘complex’ lines that leaves out the medium range.
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