For water companies who want to make their own bottles, there are two options: they can purchase preforms from converters and blow them in-house, or they can purchase resin and do the preform injection molding and the stretch blow-molding in-house.
The first option requires investment in a stretch blow-molding system.
“Bringing blow-molding in-house is a growing trend because it saves considerable shipping costs vs shipping empty bottles,” says Craig Reynolds, Husky business manager preform systems. “Blowing and filling can also be done in a ‘linked arrangement’, so the bottle is blown, filled, capped and labelled in one integrated process.”
The other route requires investment in a preform injection molding system, in addition to stretch blow-molding equipment.
“One challenge with this choice is that bottlers need to have sufficient volume to be able to buy resin economically,” says Reynolds. “Another is developing the organisation required to be efficient plastics processors – operator skills, tooling management, machine maintenance and upgrades, etc.”
Companies can choose to buy in pre-made bottles, but then require an unscrambler and a rinser.
“The biggest advantage of in-line bottle production with a blower-filler-capper block is the reduction of costs per bottle,” says Meinhard Fischer, market segment manager non-alcoholic beverages for KHS Corpoplast. “This is because transport costs are less, and air conveyors and rinsing equipment are not necessary.”
For preform injection molding, Husky’s HyPET system is available in seven sizes, for outputs between 800 and 100,000 parts per hour. Husky also offers a High Performance Package (HPP) which speeds up molder cycle time by 15%.
On the blow-molding side, Sidel has a range of blowing machines with outputs from 2,400 to 64,000 bph (bottles per hour) for bottles up to 10 litres. The SBO 24/24 and the SBO HighSpeed for blowing of bottles smaller than 70cl are the newest in this range.
Other key blow-molding kit includes the Contiform S from Krones, which can achieve outputs of up to 60,000 bph for small bottles, and the InnoPET Blomax III from KHS.
According to Krones, the only ‘must-have’ piece of inspection kit at this stage is a machine for inspecting blow-molded bottles in the discharge of the blow-molding machine.
However, it said other inspection equipment is desirable. In the preform feed to the blow-molding machine, it recommends a preform inspector for monitoring the preform’s sealing surface. In addition, in the blow-molding machine, it advises carrying out neck-finish inspection (checking the sealing surface for damage, ovality and deformation), side wall inspection (monitoring for pearling, contour, damage and coarse material distribution), base inspection (monitoring for injection point, cockling, deformation, pearling, damage and contamination) and base quality measurement (determining the base quality in regard to mass distribution).
Agr supplies an in-line system called the PETWall-Profiler, which works in conjunction with the blow-molder to provide constant monitoring that bottles are being produced in spec. Krones, meanwhile, manufactures various in-line inspection systems, including the Linatronic, Toptronic and Multitronic lines.
The first decision is whether to go for a rotary or linear filler. A Sidel spokesperson outlines the basic differences: “Linear fillers are generally for low outputs (up to 8,000 bph) and large containers, while rotary fillers are for medium or high outputs. Linear technology is simpler and the costs are more controllable; there are no mechanical turning parts that might require additional costs. Rotary fillers have more components but can achieve higher outputs.”
If on a line with blow-molding, the choice of rotary and linear will be determined by the blower. If the blower is linear, the filler will be too. Then there’s the choice between mechanical and electronic fillers.
“Mechanical is traditional technology,” says a spokesperson from Sacmi. “The filling phase is stopped when the level reaches a set point. This technology is cheap, reliable and easy to maintain. Unfortunately, it doesn’t allow a quick changeover and is less flexible than an electronic solution. Electronic is new technology, where the filling phase is regulated by flow meters. The main advantages are flexibility, simplicity, cleanliness and efficiency in the event of frequent bottle changeovers.”
To further confuse matters, there are different methods of filling. Ocme favours gravity vacuum systems for filling still water into container sizes from 25cl to two litres. For larger containers of up to five litres, it recommends net weigh filling for a cleaner fill. For carbonated water, it says counter-pressure filling is best.
KHS, meanwhile, offers rotary volumetric systems on which volume measurement is done by magnetic-inductive flow meters or turbine (impeller) flow meters.
Sacmi Filling supplies mechanical and electronic rotary fillers, with a speed range of between 6,000 and 72,000 bph. Ocme’s Hydra gravity vacuum filler comes in sizes from 40 to 120 heads, while its Libra net weigh filler is available in sizes from 20 to 60 heads. They both usually come as monoblock rinser-filler-cappers.
Other key suppliers of fillers are KHS with its Innofill NV, which is capable of up to 68,000 bph; Krones with its Mecafill VKP-PET, and GEA Procomac with its Fillstar PET counter-pressure fillers, Fillstar SF gravity filler for still water and Fillstar FX/CX volumetric electronic filler for both still and carbonated water. Sidel is developing fillers that can easily handle lightweight bottles with short necks.
“The choice with cappers is between mechanical and electronic, but electronic cappers have no particular advantages for water,” says Sidel. “The mechanical cappers then vary depending on the level of hygiene needed.”
On cap feeding, the company says: “You can use a conventional bowl feed system or the cap feeder, an efficient and hygienic alternative. The cap feeder combines the function of bulk hopper, elevator and orientor into one machine to provide efficient cap orientation and utilisation of floor space.”
Companies such as Sidel and KHS supply capping equipment either as part of a monoblock or as a standalone machine, while Ocme’s lines usually incorporate cappers from Arol or Zalkin.
Sidel has a patented concept for cap orientation by gravity on its cap feeder. With Sidel’s cap feeder, ejection can now be performed via a low-pressure blower system.
After filling, Krones says the following checks are necessary:
Nice-to-have checks include:
The new version of the Heuft Squeezer R 10 checks plastic containers for leaks, checks the fill level and checks the performance of the filler and closer heads. Modular systems can be put together to monitor that the positioning and integrity of the closures are correct as well as the presence of metal foil.
Krones technology includes the Checkmat 753HF, which is touchscreen-operated and capable of checking up to 72,000 bph. An off-line fill height tester which offers a speedy alternative to time-consuming fill point methods is offered by Agr.
Labellers can be mechanical (driven by gears, belts, chains and basic electric motors) or electronic (using servo drives and variable frequency drives controlled through the PLC). Electronically driven labellers offer faster changeovers and greater efficiency.
The choice of labeller will also be determined by the type of label you’re applying. Although pressure-sensitive labels are on the rise for more premium brands, roll-fed film labels applied using a hot-melt adhesive are the most popular choice for high volume water drinks in PET, according to Bob Adamson, vice president sales at B & H Labeling Systems. Indeed, KHS says that 99.9% of labelling enquiries it receives are concerned with roll-fed labels.
The main focus is on improvements that can help brand owners reduce costs, whether through faster speeds or the ability to cope with thinner label materials. B & H Labeling last year introduced a new roll-fed labeller called the Marathon XLA, which incorporates an advanced registration control system to help it deal with thinner labels.
The Contiroll from Krones, designed for applying reel-fed wraparound labels, is equipped with a servo-controlled labelling station, a feed roller for label transport with cut-off point control and rotating cutters for accurate label cutting. The Innoket RF 360 is KHS’ roll-fed labelling machine for medium to high production speeds.
The choice with coding is between two distinct technologies: laser and inkjet.
“Inkjet is experienced and adaptable,” says Markem-Imaje’s UK sales manager, Steve Ellison. “Small character inkjet coding has been around for more than 25 years and can be found on bottling lines around the world. Laser, on the other hand, is fast and increasingly affordable. With no printing fluids and little maintenance to worry about, laser really punches its weight but can’t quite match the application reach of inkjet.”
Equipment innovation is mainly focused on overcoming the issues of bottle perforation with laser and smeared or illegible coding with inkjet.
Domino’s S-Series laser coders are said to enable high-quality permanent laser coding without perforation, while the A-Series Plus inkjet employs fast drying inks to ensure code isn’t rubbed off.
The Markem-Imaje 9000 series of inkjet coders is said to offer faster start-up, ink replenishment while printing and simplified maintenance, while the company’s 7000 Series laser coders can code up to 80,000 bph. The Linx 4900BC uses a new ‘sticky ink’ designed to ensure permanence of codes in wet bottling applications.
A system that checks for the presence of the label and date is essential on any line, says Krones. However, the company adds that it’s also desirable to inspect the label position and rotational alignment to check the details on the label are correct and to check the date is correct.
The Heuft Finalview offers integrated closure inspection, a tamper evidence seal check, closure logo inspection, a leakage check, vacuum inspection, label inspection and verification of the correct product label, barcode and best before date.
The Checkmat EM from Krones uses four cameras to inspect the height, the rotational alignment and the precise position of the labels in relation to each other.
Lynda Searby is a special technical feature writer with a broad knowledge of the food and beverage industry.
© FoodBev Media Ltd 2020