Glass Manufacturing Equipment Lubrication

Glass Manufacturing Equipment Lubrication

The glass manufacturing industry operates some of the most thermally punishing production environments in all of industrial engineering. From the moment silica sand, soda ash, and limestone enter the furnace at temperatures exceeding 1,500°C to the final annealing and cooling stages, every piece of equipment along the line must contend with sustained radiant heat, thermal cycling, and aggressive atmospheric conditions. Proper lubrication of bearings, conveyors, and forming mechanisms is not a maintenance checkbox—it is a foundational requirement for uptime, product quality, and operational safety.

This guide examines four critical lubrication zones in glass production: float glass roller bearings that carry the glass ribbon through the tin bath and annealing lehr, lehr bearings operating under sustained radiant heat in the annealing tunnel, IS (Individual Section) machine mechanisms that form glass containers at high speed, and high-temperature conveyor systems that transport freshly formed glass through cooling and tempering stages. For each area, we identify the specific lubricant demands and match them to proven product solutions.

Glass plants face a dual challenge. On one hand, lubricants must withstand extreme temperatures without oxidizing, carbonizing, or evaporating. On the other, any lubricant that degrades, drips, or outgasses can contaminate the glass surface, creating costly rejection rates and rework. The products discussed below—Barrierta L 55/2, Klubertemp HM 83-402, and UNISILKON L 250L—each address distinct aspects of this challenge, forming a complementary toolkit for the glass production engineer.

Lubrication Challenges Across the Glass Production Line

Glass manufacturing presents a temperature gradient that spans nearly 1,500°C from furnace to cold end. At the hot end, float glass furnaces operate continuously at roughly 1,500–1,600°C, radiating intense heat into surrounding equipment. The tin float bath, where molten glass spreads across a bed of molten tin to form a flat ribbon, holds glass at approximately 600°C. As the ribbon exits the float bath, it enters the annealing lehr—a tunnel approximately 120 metres long where glass is gradually cooled from around 600°C to below 200°C to relieve internal stresses. Roller bearings throughout the lehr absorb radiant heat from the glass passing just above them, routinely reaching housing temperatures of 200–300°C depending on position.

In container glass production, the IS machine operates at a different extreme. Gob temperatures of roughly 1,100°C enter the blank mould, and the forming process runs at high cycle rates—often exceeding 10 to 15 cycles per minute per section on multi-gob machines. The mechanical links, neck ring mechanisms, mould holders, and takeout tong arms all operate within centimetres of glowing glass, experiencing both radiant heat and mechanical shock. Lubrication must function here without dripping onto mould surfaces or outgassing into the forming cavity, either of which produces defective ware.

High-temperature conveyors present yet another profile. Cross conveyors, transfer corners, and lehr mats transport freshly formed containers that may still be at 400–600°C. Bearings on these conveyors face not only heat but also moderate to high loads at relatively low rotational speeds—conditions that squeeze conventional grease out of the load zone and test boundary lubrication properties. Traditional grease-lubricated roller bearings in these zones have been documented to fail within three weeks to three months, even with daily re-greasing. When a bearing seizes on a conveyor line, production typically halts for one to three hours, and seized units sometimes require cutting torches for removal, damaging shafts and mounting surfaces.

Across all these zones, lubricants must exhibit several overlapping properties: high thermal stability and oxidation resistance to avoid sludge formation at temperature; low volatility to maintain film thickness over extended service intervals; adequate load-carrying capacity for low-speed, high-load bearing conditions; chemical compatibility with seal materials and metal alloys; and minimal tendency to drip, migrate, or produce residues that could contaminate glass surfaces. The cost of getting lubrication wrong in a glass plant is measured not only in bearing replacements and maintenance hours but in lost production, rejected ware, and fire risk from grease accumulation on hot surfaces.

Recommended Lubricant Products for Glass Manufacturing

Barrierta L 55/2 — PFPE-Based High-Temperature Grease for IS Machines and Float Glass Bearings

Barrierta L 55/2 is a premium long-term grease built on perfluorinated polyether (PFPE) base oil with a polytetrafluoroethylene (PTFE) thickener. This PFPE-PTFE combination delivers a continuous operating temperature range of -40°C to +260°C, making it a direct match for the thermal demands of IS machine mechanisms and float glass roller bearings operating near the hot end. With an NLGI grade of 2 and a base oil viscosity of approximately 420 mm²/s at 40°C (roughly 40 mm²/s at 100°C), it provides a stable lubricating film even under the slow-speed, high-load conditions typical of lehr roller bearings.

In IS machines, Barrierta L 55/2 serves multiple lubrication points: gob distributor mechanisms, neck ring assemblies, mould holder slides, takeout tong arms where temperatures can exceed 200°C, and the link bearings within the mould open/close drive train. Its fluorinated chemistry means it does not react with most aggressive media encountered in glass plants, including acidic vapours that may evolve from certain glass batch formulations. The extremely low evaporation rate at elevated temperatures—a characteristic of PFPE fluids—enables extended relubrication intervals compared to conventional synthetic or mineral-based greases, reducing maintenance interventions in areas that are difficult to access while the line is hot.

For float glass roller bearings, Barrierta L 55/2 is suitable for table roller bearings in the transition zone between the tin bath and annealing lehr, as well as for lehr roller bearings operating under radiant heat. It is compatible with most bearing seal materials, including fluoroelastomers (FKM), and its chemical inertness means it will not attack painted surfaces or plastics used in adjacent equipment. The product carries NSF H1 registration for incidental food contact, a relevant consideration for container glass plants producing bottles and jars for the food and beverage industry.

Klubertemp HM 83-402 — Extreme-Temperature PFPE Grease for Lehr Bearings and Hot Conveyors

Klubertemp HM 83-402 shares the PFPE-PTFE chemistry platform with Barrierta L 55/2 but is specifically formulated and marketed for severely heated rolling bearings in glass forming equipment and high-temperature conveyor systems. Its operating temperature range of -30°C to +260°C, combined with an NLGI 2 consistency, makes it particularly well-suited for lehr roller bearings and cross-conveyor bearings that experience sustained radiant heat from freshly formed glass containers.

Where Klubertemp HM 83-402 distinguishes itself is in load-carrying performance at elevated temperatures. With a four-ball weld load of 8,000 N or higher, it provides a margin of protection against adhesive wear under the boundary lubrication conditions that prevail in slow-moving lehr bearings and conveyor idlers. These bearings typically operate at rotational speeds of 10 to 30 rpm with bearing load ratios (P/C) in the range of 0.25 to 0.50, meaning the lubricant film is repeatedly squeezed and must rely on its anti-wear additive chemistry and solid lubricant contribution from the PTFE thickener to prevent metal-to-metal contact.

The product is available in three NLGI grades—HM 83-401 (grade 1), HM 83-402 (grade 2), and HM 83-403 (grade 3)—allowing selection based on application method and housing configuration. The grade 1 variant can be pumped through centralised lubrication systems, while grade 2 is the general-purpose choice for manual or automatic single-point application. Klubertemp HM 83-402 also demonstrates resistance to aggressive chemical media including concentrated acids, alkalis, and organic solvents, an important property in glass plants where cleaning agents and process chemicals may contact bearing housings.

UNISILKON L 250L — Silicone-PTFE Grease for Valves, Seals, and Plant Ancillary Equipment

UNISILKON L 250L is formulated with methyl silicone oil and PTFE thickener, producing a white, fibrous grease with an NLGI grade of 3 and an operating temperature range of -45°C to +160°C. While its upper temperature limit is lower than the PFPE-based products, its value in a glass manufacturing plant lies in the extensive network of ancillary equipment that supports the production line: water-cooling circuits, pneumatic control valves, hydraulic fittings, steam systems for cullet washing, and compressed air delivery networks.

Glass plants rely on large volumes of cooling water circulating through furnace components, forehearths, and mould cooling systems. The valves and fittings in these circuits—often involving ceramic or hard-coated internal components—benefit from UNISILKON L 250L's broad compatibility with metals, thermoplastics, and elastomers. Its high base oil viscosity (approximately 1,350 mm²/s at 25°C) provides durable film strength on sliding surfaces, and its resistance to hot water and steam up to approximately 130°C makes it appropriate for valve stem sealing and O-ring assembly in cooling circuit components.

The product also serves as an excellent assembly lubricant for radial shaft seals, O-rings, and gaskets throughout the plant, reducing the risk of seal damage during installation. UNISILKON L 250L carries multiple international drinking water certifications—including KTW-BWGL (Germany), WRAS (UK), ACS (France), and NSF Standard 61—plus NSF H1 food-grade registration. This compliance profile is particularly valuable for container glass plants producing food and beverage packaging, where lubricants used on equipment in proximity to the product stream must meet stringent safety standards.

Application Practices for Glass Industry Lubrication

Selecting the correct lubricant chemistry is the first step; applying it correctly in the field determines whether the full performance potential is realised. High-temperature PFPE greases such as Barrierta L 55/2 and Klubertemp HM 83-402 are chemically incompatible with conventional greases based on mineral oil or PAO synthetics. Before switching to a PFPE grease, bearing housings and feed lines must be thoroughly cleaned of all previous lubricant residues. Klüber recommends a two-stage cleaning procedure: first flushing with petroleum ether (boiling range 180/210) to remove bulk old grease, followed by Klüberalfa XZ 3-1 cleaning fluid to rinse dissolved residues. Mixing PFPE grease with even small amounts of conventional grease can produce softening, separation, or accelerated degradation at temperature.

Grease fill volume is another critical parameter. For lehr roller bearings and cross-conveyor bearings operating at low speeds (under 50 rpm), a housing fill of 70 to 90 percent of free volume provides maximum contamination exclusion while the low speed prevents excessive churning and heat generation. For higher-speed bearings—such as fan bearings on lehr cooling air systems or takeout mechanism drive components—fill should be limited to 30 to 50 percent of the bearing free volume. Over-greasing high-speed bearings increases operating temperature, accelerates oxidation, and can force grease past seals into areas where it may contact hot glass.

Relubrication intervals should be established through condition monitoring rather than fixed schedules wherever possible. Measuring bearing housing temperature with infrared thermography or permanently mounted thermocouples provides early warning of impending lubrication failure: a gradual temperature rise of 5 to 10°C above the established baseline typically indicates grease depletion or degradation before audible or vibration-based symptoms appear. When relubrication is performed, new grease should be purged through the bearing until clean grease exits the seals—this ensures complete removal of degraded, contaminant-laden old grease from the load zone.

For UNISILKON L 250L in valve and seal applications, apply a thin, even film to mating surfaces. Excessive application provides no additional sealing benefit and may attract airborne dust or glass particulate. When using UNISILKON L 250L as an assembly aid for shaft seals, verify compatibility with the specific elastomer grade through a coupon test or manufacturer data—silicone base oils can cause swelling in certain silicone rubber formulations despite generally broad compatibility.

Storage conditions directly affect product shelf life. PFPE and silicone greases should be stored in their original sealed containers in a dry, frost-free environment. Klubertemp HM 83-402 carries an approximate shelf life of 60 months from manufacture when stored correctly; UNISILKON L 250L approximately 36 months. Containers should be kept tightly closed when not in use and protected from direct sunlight and moisture ingress.

Key Takeaways for the Glass Production Engineer

Glass manufacturing places a unique combined demand on lubrication: extreme thermal stability, low volatility to protect product quality, and robust load-carrying capacity under slow-speed boundary conditions. The three products profiled here address distinct points on the plant's temperature gradient. Barrierta L 55/2 and Klubertemp HM 83-402 provide PFPE-based performance for the hottest zones—IS machine mechanisms, float glass roller bearings, lehr bearings, and hot-end conveyors—with continuous service capability to 260°C. UNISILKON L 250L complements these with silicone-based sealing and valve lubrication for water-cooling circuits, pneumatic controls, and plant utility systems up to 160°C. Together with a disciplined programme of cleaning, correct fill volumes, and condition-based relubrication, these products support the uptime, safety, and product quality outcomes that define a well-operated glass production line.

KOEED Support

For technical consultation on selecting and applying lubricants for your glass manufacturing equipment, or to request product specifications and safety data sheets, please contact our team. We provide product sourcing, technical guidance, and application support for Klüber Lubrication products and complementary industrial lubricant lines.

Email: Moritta@KOEED.COM