What are lubricants? Lubricants minimize the friction that occurs when two parts come into contact. They can also lessen or prevent oxidation and corrosion, create a seal that safeguards against dirt and dust, serve as power transmission, and regulate heat in certain applications.
Four types of lubricants are prevalent in commercial and industrial applications: oil, grease, and penetrating or dry lubricants. Understanding these types and when they should be used or not used will help you choose the ideal one for your application.
Oil is a thin lubricant available in multiple viscosities, or weights. A low-weight oil is thinner, while a high-weight one is more viscous. Oil-based lubricants contain additives to either enhance or suppress specific characteristics inherent to the oil. Oil type and its application will dictate the necessary additive amount, such as dispersant in engine oil. The base for oils comes in mineral, vegetable and synthetic varieties, or a mixture of any of the three, to offer different properties. Biodegradable or low-toxicity oils are preferable for their environmental safety, whereas synthetic versions are ideal for extreme conditions.
When to Use Oil
Oil lubricants provide low-resistance lubrication compared to grease. They’re suitable for tasks like blade sharpening and bearing or hinge applications.
When Not to Use Oil
Oil isn’t suitable for wet, dusty or otherwise dirty surfaces. When oil combines with contaminants like dirt, it can increase friction rather than decrease it, and the oil lubricant can gum up. Oil can also absorb water when applied to a wet surface, causing the lubricant to lose adhesion to the part or component that you’re lubricating and wash away.
Grease is an oil-based lubricant with additives and thickening agents to increase its self-lubricating properties. These might include molybdenum disulfide, graphite, polytetrafluoroethylene (PTFE) or other solid particles. The lubricant provides a stickiness that helps it adhere to surfaces, protecting them from damage and corrosive degradation.
When to Use Grease
Grease is an ideal substitute for oil when oil’s enhanced cooling properties are not necessary. Grease is suitable for linkages, chains, bearings and gears, particularly when you require stickiness to adhere a lubricant to the surface for an extensive time frame. Grease can also provide sealing protection against moisture and dust.
When Not to Use Grease
Grease isn’t suitable for lubricating fine or fast-moving machinery parts as it could actually create resistance or slow down the machinery’s operations.
When removing a rusty part like a bolt or nut, a penetrating lubricant can loosen even years’ worth of corrosion or debris. Penetrating lubricants enter tiny surface cracks and crevices on a metal part to break down rust. They’re also suitable for wire ropes, as the evaporative solvent in penetrating lubricants enhances the lubricant’s migration into the rope’s core. The lubricant evaporates, leaving behind a protective lubricating film on each wire rope strand.
When to Use Penetrating Lubricants
Penetrating lubricants are ideal for warehouse repair and maintenance tasks, such as loosening nuts and bolts. They’re also suitable for lubricating cables, chains and wire ropes.
When Not to Use Penetrating Lubricants
Penetrating lubricants are only suitable for certain tasks and can’t replace other lubricants in their ideal applications.
Dry lubricants are composed of self-lubricating materials in tiny particles, including molybdenum disulfide, graphite and PTFE. Users often mix these dry particles with fluids like solvents, alcohol or water and apply them as a spray. The liquid mixer will evaporate over time, leaving behind a slick, microscopic surface film that provides effective part lubrication.
When to Use Dry Lubricants
Dry lubricants are the optimal choice to lubricate machine components that must perform at high-precision levels. They keep a part’s surface clean and don’t cause gunk build-up like grease. These lubricants can also withstand extremely high temperatures and pressure that would oxidize oils.
- Actuating ball and lead screws
- Threaded rods
When Not to Use Dry Lubricants
Fluids can wash away dry lubricants, so you shouldn’t use this type in applications where the part’s surface may be exposed to solvents or liquids.
Certain applications rely on specialty lubricants for their unique properties.
Gear oils safeguard gear teeth and the gears themselves against wear and abrasion. They offer thermal stability to keep sludge from building up on these components.
Compressor oils provide lubrication for rotating compressor parts to lessen or eliminate friction. They also transfer heat from the compressor to cool it during air compression and help seal the compression chamber.
Solid Bar Lubricants
Solid bar varieties lubricate components within rotary dryers and kilns to maintain proper operation and reduce wear that can cause misalignment and refractory loss. The lubricant goes in a kiln between the shell and tire bore, coating the bore in a protective film.
Learn More With Lubrication Engineers
Lubricants are available for virtually every application, providing lubrication, protection, sealant and heat transfer, as needed. Choosing the ideal lubricant for your application is essential to prevent premature part or machinery failure. Lubrication Engineers partners with companies worldwide, providing reliable lubrication solutions since 1951. Our expert staff formulates and produces LE lubricants with proprietary additives in-house to ensure high-quality products. We also offer comprehensive services including oil analysis, audits, assessments, and training.