|Quality compounds for quality forming|
By Peter Finch for Glass Machinery Plants & Accessories
What your research department tells you may not always be what the market wants to hear. Such was the case at high-temperature lubricant engineers Renite company in the early days of is bottle making machines. But since the quality of the glass finish is so closely related to the quality of the compound applied to the mould, Renite held back in introducing into its compounds sulphur and grease - which it felt were not wholly suitable ingredients until its own research opened the doors to the more efficient use of these materials. Renite’s highly skilled product development team then wasted no time in integrating them into the company’s range of mould treatments.
Nearly 70 years of product research, development and production have established Renite Company among the world leaders in the field of industrial lubrication, an innovator at the service of the glass and metal sectors.
Today, the company ships its products around the globe, to as far a field as Indonesia, South Africa and Trinidad. The loyalty of its clientele and the consolidated quality of its lubricant range have certainly not led to complacency, however. Renite continues to allocate substantial resources to the development of new, enhanced lubricants and applications, keeping pace with a glass industry where machine speeds and production volumes are constantly increasing.
Renite’s principal sphere of interest is the hot forming of glass pressware and containers developing and producing mould swabbing compounds, mould spray lubricants and application equipment, pre-treatments, coatings for delivery and transfer equipment, and recirculating lubricant supply tanks. The company also produces special dry film coatings for moulds, rings, plungers, baffles and mandrels, as well as special lubricants and greases for high temperature furnace applications.
Renite Company was founded by Harry M. Reynolds in Columbus, Ohio, United States, in 1932. Reynolds saw the need for a more scientific approach to the lubrication of glass-forming moulds. In the 1930s, in fact, standard procedure was to rub the iron moulds with old rubber shoe heels and powdered sulphur!
The Midwest of the United States had rich deposits of silica sand and, consequently, many early American glass manufacturing operations were based in the states of Indiana, West Virginia, Pennsylvania and Ohio. Although glassmaking has tended to diversify closer to market centres, Renites 2,800-sq.m. site, purpose-built in 1972, remains well placed to access both local and international markets.
It was in the town of Columbus, then, that Reynolds set up his first production facility. The small, rented premises soon became a hive of pioneering activity in the development of compounds and application equipment for pressware moulds.
The first liquid sprayable compound to emerge from Columbus was Renite H, small particles of graphite suspended in high purity oil. When the compound impacted with the hot glass mould, the oil vaporized as smoke and left a graphite deposit over which the hot glass flowed easily and which allowed trouble free release once the glass solidified.
In collaboration with a Columbus-based mechanical engineer, Haz Okey, Reynolds later developed the first custom-designed, totally heat-resistant atomizer, the Renite Model E, able to work under extreme heat conditions and apply finely regulated quantities of Renite H. Both atomizer and lubricant are still used around the world today.
SETTING FIRM PRIORITIES
The company’s relationship with the glass bottle-making business has not always been an easy one. Initially, Renite’s pressware technology was perfectly suitable for the slow-moving Lynch- and Miller-type forming machines, which used open, freestanding moulds. In the mid-late 1940s, however, Renite did start producing swabbing compounds for situations where spray lubricating was impractical. The advent of Hartford IS machines through the 1950s represented a turning point for the glassmaking industry and its technology suppliers. The machines were much faster and much more complex, the moulds (needing surface treatments) got much hotter and the moving parts (needing lubrication) were much less accessible.
At this point, Renite decided to dedicate maximum time and resources to the development of an automatic mould spray lubrication system for the new IS machines, but also, more significantly, to rule out the use of sulphur and grease in its swabbing compounds, despite the fact that many machine operators were adding these ingredients to standard Renite compounds at the time.
During the 1960s, 1970s and into the 1980s, Renite actively
discouraged the introduction of sulphur and grease on technical grounds. Meanwhile, the competition was growing in strength, with Renite’s rivals offering machine operators sulphur and grease-based products that were not available from Renite.
KEEPING TOUCH WITH THE MARKETMarket demand remained a vital factor in product development strategy at Renite, however, and research into the use of sulphur and grease continued. In 1982, Renite researcher Dr. John Terence Golden presented a study to the American Ceramic Society, which indicated that small amounts of well-dispersed sulphur would be effective in glass mould applications without the pitting effects which had previously justified Renite’s hostility. As a result, Renite gradually began to make more use of sulphur but, where possible, preferred wax thickeners to the metal soap grease ones.
The company’s response to the sulphur and grease merchants was Renite F-5, a wax-thickened lubricant which contains no metal soap grease and is thus a much cleaner application. The only drawback for operators was that, with the Renite products, moulds had to be swabbed more frequently.
Compound development continued apace: the development of automatic lubricant spraying equipment for IS machines slowed. Renite’s view remains that the design of traditional IS machines is not compatible with the retrofitting of add-on spray units. Until such systems are built into the design of the IS machines, reasons Renite, manual swabbing will continue to be the most effective, albeit more time-consuming, system.
In 1987, Renite decided to stop further research into the development of automatic lubrication systems for IS machines and to focus on more competitive, carefully researched swabbing compounds. By the mid-1990s, the company had a full range of swabbing compounds and coatings (with or without sulphur; grease or wax-based) on the market. It includes smokeless mould spray lubricants, shear spray concentrates, shear spray atomizers, dry delivery coatings, scoop lubricants, swabbing compounds and ring dopes, as well as coatings for transfer areas and lehr mats.
A main concern of machine operators is to reduce the need for and frequency of manual swabbing. Time spent swabbing is obviously time spent not turning out glass containers. Apart from add-on automatic spray lubrication systems, the only other way of limiting, or even eliminating, the need for swabbing is by pretreating the moulds before they are put into service.
Currently, though, swabbing is virtually essential in the production of high quality glassware, ensuring that exactly the right amount of lubricant is applied in exactly the right place. Renite’s precoatings have helped eliminate the need for swabbing at startup and reduce the need for swabbing during production, and the company continues to research this type of application.
In the early 1990s, Renite introduced a new line of semi fluid products specifically prepared for the newer IS machines, and has since also developed a new
generation of swabbing compounds which includes the general purpose blank mould treatment Renite F-71.
When swabbed on the hot mould surface, F-7 I leaves a firmly bonded, graphitic, solid film coating. Initial tests showed it was possible to increase the swabbing interval from 30 to 45 minutes, compared to previously applied compounds. In actual use, machine operators soon reported interval increases of 25 to 50 per cent, depending on the type of job. There was also a subsequent drop in the consumption of lubricant, with a drum going about a third further. Operators also reported less smoke, less marking of glassware and less spattering.
Other more recent additions to the product line are Renite F-94 and Renite H-8.
F-94 is a lighter blank mould lubricant for use where extra cleanliness is required. Renite’s new gel-like F-7 I and F-94 compounds were both designed for dry swabbing on blank moulds and not for use as ring dopes, an application for which H-8 was developed.
H-8 is a ring lubricant which is a lighter and more fluid equivalent of Renite’s F-7 I. It is particularly useful in narrow neck press and blow (NNPB) operations involving hollow necks and thin glass in the neck area.
SECRETS OF SUCCESS
In charge today at Renite Company is Stephen M. Halliday, son-in-law of the founder. He took over as President and Board Chairman on the death of Harry Reynolds in 1989.
“We have kept up with technology, kept good employees, watched the bottom line, produced quality products and provided excellent services,” says Halliday, a man who, with over 40 years of service at Renite behind him, is clearly very well qualified to explain the reasons for the company’s longevity and success.
And so, as the glass container industry continues to change, Renite continues to deliver, offering enhanced lubricants and applications to an ever demanding market.
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Article reprinted from Glass Machinery Plants & Accessories Issue no. 2/01 by Artech Publishing S.r.l.