American glass packaging maker O-I recently opened a third furnace at its New Zealand factory in Penrose, Auckland. The new furnace, which injected $125 million into our local economy and into the pockets of contractors, increases the factory’s efficiencies considerably. The factory expansion also created around 40 new jobs, increasing the number of staff at the site to 230.
New Zealand’s only glass packaging producer, O-I was formed in 1903 in the US state of Ohio, when the founder, Michael J. Owens, patented a machine that could automatically produce four glass bottles per second. The company has been in New Zealand since 1922.
Steve Bramlage, general manager O-I New Zealand, says the new furnace uses the latest global glass manufacturing technologies to produce quality glass packaging to meet the short and long-term needs and expectations of New Zealand customers and consumers.
“This significant investment in our Auckland plant highlights our commitment to supporting the future growth of New Zealand's food and beverage industries,” he comments.
The expansion saw the building of a new furnace that adds 250 tonnes of molten glass per day going into the existing six packaging production lines. In addition, a part of the new production line is now modified to make use of O-I’s award winning narrow neck press and blow bottle making technology. The furnace increases the factory’s annual product output by 90,000 tonnes a year.
The furnace, however, adds qualitative value, too. The innovative proprietary technology it uses impacts positively on its resource usage footprint.
From sand to glass
Glass is nature’s gift to mankind. The basic glass manufacturing process remains similar to that first used by the Egyptians around 3000 BC and refined over the centuries. Today it is a sophisticated and highly technical process focused on efficiency and high safety standards.
Raw materials of sand, limestone, soda ash, colouring agents if required, and recycled glass, or cullet, are stored in compartments in the O-I plant’s Zippe batch house. They gravity feed into the weighing and mixing area according to the batch mixture’s recipe. The mixture is then elevated into batch hoppers, from where Zippe conveyors take it to the glass furnaces.
The new furnace enables O-I NZ to almost double its use of cullet (recycled broken or waste glass) from 84,000 to 154,000 tonnes per annum. Its use of recycled content in New Zealand averages approximately 60 percent. Recycled content often reaches 70 percent for green coloured glass used by the wine industry.
Recycling company Visy NZ, which has a plant in Onehunga, supplies the cullet. Without O-I NZ, there would be limited recycling options for waste glass, and the majority would go to landfill.
The furnace heats the batch mixture to between 1100 and 1590 degrees Celsius, creating molten glass. Firing is by natural gas through the side ports of the furnace. O-I NZ uses electricity derived from renewable hydro, geothermal and natural gas sources. Most other countries in the world do not easily match this level of renewable energy, Bramlage says.
Glass can be recycled infinitely with no loss of purity. The more cullet in the batch mixture, the lower the temperature required to melt the mixture to molten glass. This provides a significant reduction in carbon emissions.
Evidence suggests every 10 percent of recycled glass used in new glass production cuts carbon emissions by about five percent and reduces energy use by some three percent. And, according to Bramlage, O-I’s current use of recycled glass (36 percent globally) already generates enough savings to more than offset emissions produced by its finished goods transportation.
The new furnace consists of an 83-square metre end port, deep refiner end melter with blanket and barrier boost. Constant supervision and monitoring via sophisticated computer-based controls enable economical raw material melting in the furnace.
The molten mixture now goes to a refiner, where impurities are screened out, then to a fore hearth where the glass is cooled down, or conditioned. From there it runs from the furnace through two feeders into the bottle forming machines attached to each furnace. A bottle forming machine has sections, each which contain bottle or jar moulds. A mould comprises 11 separate pieces and a large forming machine can carry as many as 30 moulds.
The feeder cuts the molten glass stream into gobs, with one gob going into each mould. A gob will form a single glass container. Building on the original Owens bottle machine, O-I forming machines and moulds are proprietary designs. The O-I team uses two techniques to form the glass container in the mould, each technique consisting of two stages:
• In the first stage, a gob falls into a mould. Either compressed air or a metal plunger enters the mould from the bottom to hollow out the gob. The air or plunger creates the container’s mouth and presses the molten glass upwards to the sides of the mould. The result is a partially formed container, or parison.
• In the second stage the machine transfers the parison to another mould, reheats it, then releases compressed air into the mould through the parison’s mouth. This hollows it out completely and the parison now takes on the mould’s shape entirely, creating the container. The production line that works from the new furnace uses press and blow technology.
The technology itself has been in use a long time, but only recently for bottles with narrow necks. O-I’s advanced narrow neck press and blow (NNPB) technology resulted in its Lean+Green® lightweight wine bottle range, which has won five Australian awards (most recently for the Consumer Category at the 2010 Australian International Design Awards) since the company launched the technology across the ditch in 2009.
Lean+Green wine bottles are between 18 and 28 percent lighter than their predecessors. In addition to using raw materials more efficiently, NNPB also delivers large savings in water, energy and emissions, while maintaining bottle proportions and design integrity.
The process also enables a 20 percent reduction in energy use to produce the same number of bottles, representing a saving of more than 11,130 tonnes of carbon dioxide per annum. There is an average 12 percent drop in water usage per container, and around 840 more bottles (an increase of 6.25 percent) can be packed into a 20-foot shipping container
However, the challenge of NNPB techniques is the thinner the plunger, the more problems there are with its efficiency and durability. The metal plunger used in the NNPB process must not only form the parison, but must also extract sufficient heat to stabilise the parison when it enters the compressed air blow stage, without causing chill defects in the final product. Jealously guarded NNPB trade secrets consequently have a lot to do with plunger material, the cooling system design, and the environment in which it operates.
Making containers safe and durable
The formed containers are now annealed. Glass is a poor conductor of heat. It cools unevenly when it emerges from the forming machine. The containers pass through a long, flat oven, or lehr, where they are reheated to 550 degrees Celsius, then gradually cooled until they emerge at the cold end an hour later. This process reduces residual stresses inside the glass. In addition, the bottles are given two surface treatments during this process.
The treatment at the hot end consists of ‘certincoat’, which helps containers maintain their strength. The treatment at the cold end consists of ‘duracoat’, which helps prevent scuffing. Both surface treatments aid bottles to move smoothly along a bottle plant’s filling line.
Finally, the containers pass through electronic inspection machines that automatically detect faults. The inspection comprises a wall thickness inspection, squeeze testing, sealing surface inspection, sidewall scanning, and base scanning. Information from the quality inspection machines continually relays to the forming machine operators, who make adjustments to rectify problems. Rejected bottles go back to the raw materials area for meltdown.
Off to market
Bottles that pass inspection are packed in shrink wrapped pallets that may contain up to 5,000 bottles in up to 11 layers. The O-I team supply companies including Pernod Ricard, Villa Maria, Lion Nathan, and DB Breweries. The new furnace increases the availability of locally made glass packaging, ensuring security of supply and providing shorter lead times and freight efficiencies for customers.
“New Zealand’s renowned beer- and wine-making industries will benefit from having a sure supply of locally produced glass packaging,” Bramlage says. At the opening ceremony on December 1 last year, PM John Key said that O-I’s investment was a good example of how Kiwis could “embrace the international world to produce product which is critical for the New Zealand economy. We’re generally trying to make New Zealand a more attractive place to invest," Key said.