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There are several different types of lubricants that are typically used in industry. The basic purpose of lubricants is to ensure that moving parts operate smoothly and friction is reduced. Using the right lubricant can minimize the need for unscheduled maintenance; help to prolong the life of the machine components, and ultimately save money.
Lubricants can be categorized into two main types: organic and synthetic. Most organic lubricants are prepared from petroleum through the refining process. Synthetic lubricants are prepared using a complex process of chemical compounds and additives. Additives are chemical components which are added to the base oil to improve the performance of lubricants. Although the basic function of lubricants remains the same, typical enhancements include oxidation stability, wear protection, and corrosion inhibition.
Viscosity is the thickness, or resistance to flow, of oil. Various organizations have different scales on which oil viscosity is measured. The International Organization for Standardization (ISO) and Society of Automotive Engineers (SAE) each assigns a grade number. Oils with higher numbers are thicker than those with lower numbers.
Additives improve specific characteristics of oil, such as load capacity and corrosion resistance.
• Detergent additives prevent sludge and other engine deposits by keeping unwanted particles suspended in the oil. These suspended particles are later removed when the oil passes through a filter. Detergents are most commonly found in engine oils.
• Non-detergent oils are suitable for applications in which the formation of sludge and other deposits is not a problem and no filter is present.
The following types of oil are used in roll forming equipment:
• ISO grade 460 (SAE 140) gear oil is used in sealed gearboxes. Gear oil has extreme pressure additives that strengthen the non-detergent oils to withstand heavy loads found in gears and gear-drive systems.
• Way lube oil is applied to press rails and linear slides. This oil is formulated to reduce friction and wear. It is non-detergent oil that ensures smooth, uniform motion of ways and slides.
• Hydraulic oil is used in hydraulic presses or clamping systems. Anti-wear additives make these non-detergent oils the best choice for hydraulic systems and equipment.
• Slick 50 can be applied to the roll space portion of the mill spindles. It is a synthetic oil-based treatment that protects from friction and heat. It helps reduce corrosion due to condensation between the bore of the roll and the outside diameter of the spindle.
Grease can be formulated for conditions such as high temperatures, extreme pressure, and varying loads and speeds. It also resists moisture to prevent corrosion. Grease is a semi-solid, made of base oil, thickener, and additives. Base oils do the lubricating. Petroleum oil is the most economical. Synthetic oil (non-petroleum) lasts longer and can generally withstand higher temperatures. Semi-synthetic oil (a blend of petroleum and synthetic) balances lower cost with longer-lasting performance. Thickeners are solid particles that hold the base oil in place.
The chart below is a guide for comparing the relative properties of the most common thickeners.
|Thickener||Heat Resistance||Water Resistance||Oxidation Resistance|
* Oxidation of lubricants can produce sludge, varnish, gum and acid.
The NLGI (National Lubricating Grease Institute) rates grease by its consistency on a numeric scale. The most common NLGI number is 2. Lower numbers are softer and flow better, while higher numbers are firmer, tend to stay in place, and are a good choice when leakage is a concern.
Additives improve the characteristics of the grease, such as temperature range, corrosion resistance, wear resistance, adhesion, and load capacity. Additives that improve load capacity, such as moly (molybdenum disulfide), are also known as extreme-pressure (EP) additives.
The following types of grease are used in roll forming equipment:
• EP 2 grease is used for lubricating bearings. It is fortified with extreme-pressure additives. This grease can handle heavy, suddenly applied (shock) loads in bearing applications.
• High-temperature grease should be used in weld boxes, and other equipment that is subjected to temperatures above 200°F. Even at high temperatures, these greases maintain their consistency.
• Chain and open-gear grease is used on chain couplings, chain-driven components, and open-spur gear drive systems. This grease, with moly, resists wear and is great for extreme-pressure applications.
Information and technical data derived from McMaster-Carr.
Written by: Matt Hozjan, Equipment Assembly Supervisor