Question of cost

A company that wants to know if an investment will ultimately pay off must include not only just the cost of acquisition, but calculate what is known as the total cost of ownership (TCO) as well. In other words, without calculating the TCO, there is little incentive for an industrial enterprise to invest in a new machine or line for example. This approach shows the potential for optimization and cost reductions. In the field of PET bottling lines the container itself is increasingly becoming the center of attention.

The focus is on efficiency and sustainability in practice. KHS thus acts in response to its customers’ desire for further PET bottle weight savings with its Bottles & Shapes concept. This comprehensive service is a unique consulting portfolio for the design and development of plastic bottles. This portfolio includes optimizing bottle weights and calculating the TCO.

Each gram of PET saved results not only in material savings, for example, but also to lower compressed air and energy consumption during bottle production (See How do we reduce compressed air consumption under Check 4).

The following is an example of how much a beverage bottling plant can save per year on material costs alone by reducing the weight of PET bottles:

• at 150 million filled PET bottles per year
• two-gram weight reduction per PET bottle
• average price for PET of 1.40 euros per kilogram

The result: up to 420,000 euro lower costs annually for a bottling operation.

As part of its Bottles & Shapes concept, KHS of course provides advice on how much less weight the PET bottles may have compared to the previous technical solution without altering the stability of the bottles or creating difficulties in subsequent steps of the production process in the line.

This involves the following primary general questions: Which products are to be filled? Which filling technology is to be used? And regarding the related analysis: how high are the loads the bottles are exposed to in the line? And, what expectations do retailers and consumers have?

The easiest way to lighten the bottle weight is to reduce only the wall thickness. This, however, could result in a lower stability quite perceptible to the consumer. If this is a disadvantage, the experts at KHS consider whether an increase in stability is possible for the bottle design to be optimized by reinforcing the ribbing geometry or changing the cup base, for example. The wall thickness can then be reduced based on increased stability. Incidentally, implementing the focus lamp is another recently offered weight-reducing option. This focuses an exactly defined linear heat ray on the critical area below the neck ring without burdening the sensitive neck area with heat radiation. By utilizing this previously unstretched mater­ial, lighter preforms can be used for the production of PET bottles.

Numerical simulations provide fast and exact solutions for the development of container contours. They apply all known influences with the help of a comprehensive material database. In addition, 3D drawings serve as templates for prototypes of the ideal containers determined. A 3D printer optionally creates a model from this prototype within a minimum amount of time.

The next step in the Bottles & Shapes process: based on a specially made pilot scale preform, sample bottles are produced on a laboratory machine which operates ex­actly like the stretch blow molder used in practice later. Efficiency, blow molding pressures, and the temperature profile used to heat the PET preforms and blow molds - all process-related settings are ready for retrieval. The containers are not released for production and initial practice tests until the results of the laboratory test have met all given specifications.

The stretch blow molders of the InnoPET Blomax Series IV generation offer sensible solutions: exceptionally exact and gentle control of preforms / no elaborate transfer mechanisms / near infrared radiation for fast penetration of heat through the preforms / a servomotor carries out the stretching process at the same rate of speed even at varying machine speeds. The result is high process stability and a low reject rate.

Another key advantage of processing lightweights: the lighter the preforms, the less energy the stretch blow molder heater needs. The heat is reduced in direct proportion to the decreased preform weight. Another effect: reduced blow pressures for the stretch blow molding process.

It is possible to invest in the new Airback Plus system from KHS. Airback Plus is used in conjunction with KHS’ Airback system established on the market that saves up to 40% on compressed air. This also enables the user to install a smaller and more cost-effective compressor.

High line availability is decisive for a good TCO figure. Particularly those lines used for processing lightweight plastic bottles require especially technically demanding solutions. The InnoPET Blomax Series IV can be simply connected to existing KHS PET filling systems and with its Feedflow option, offers gentle conveying of preforms weighing even less than grams. A horizontal feed segment and a fre­quency controlled blower motor ensure a variable and uniform flow of materials independent of the force of weight, coupled with automatic capacity control. All other process steps thus remain stable.

A recommended option for lightweights such as those to be filled with still beverages is to place a drop of liquid nitrogen in the headspace of the bottles. This nitrogen creates pressure inside the containers thereby making them overall more stable. The cost of a nitrogen unit must of course be included in the TCO calculation. The increased bottle stability obtained by this facility ensures reliable further processing within the line - container conveying for example. An investment that pays off.

Within the scope of the Bottles & Shapes program, the experts from KHS are always searching for (further) technical options that enable gentle handling of lightweights - or with which direct cost benefits are possible. Here are some typical examples.

Completely gapless plastic mat top chains are ideal for conveyors. The PET bottles travel as if on seamless carpet. The benefits include gentle materials handling within the same footprint - deformation and tipping are reduced to a minimum.

KHS Direct Print, the new method of direct digital printing using UV inks, offers a wide range of benefits especially for labeling lightweights. Thanks to the non-contact printing process, containers can be designed so that they are even lighter in weight than for the classic method of labeling. For this purpose, the containers are additionally pressurized with sterile air before printing.

The variable-position hot air nozzles of the KHS shrink tunnel concept ensure optimum shrinking results. The air flow can be set up based on the requirements of each bottle design to be processed and oriented to the desired type of packaging.

With the Nature MultiPack powered by KHS, a revolutionary technology is now in the market as the latest innovation in the formation of multi-packs. This system involves applying dots of a special adhesive to each of the bottles and then sticking them together. In comparison to film packaging, Nature MultiPack requires up to 85% less packaging material and saves up to 67% on energy during production. This can also improve the TCO for a line further.

Conclusion: As a turnkey supplier, KHS provides comprehensive advice on all aspects of lightweighting and TCO that is second to none. This gives customers assurance with regard to the financial and sustainability aspects over the entire life span of a system prior to investing in a new machine or a system upgrade. Generally frequently evident in the industry is the trend towards an initially higher-priced initial investment for which the TCO figure is generally considerably more positive than for compromise solutions. There’s no doubt about it.