Lubricants protect your components from wear and corrosion and should be treated as critical design component. But different lubricant chemistries are better suited for different designs and the wrong lubricant can do your application more harm than good, you want to make sure that your lubricant is compatible with your application's operation requirements. Here are some things you should consider when selecting a lubricant for your application:

1. Temperature

The most important parameter is temperature. All lubricants have specific temperature ranges for optimal performance. Some lubricants have a broad operational temperature range, some ones are more suitable for lower temperature, some other ones are designed for high-temperature applications. Knowing the temperature of the system required enables to select a lubricant that will provide optimum operating life and performance.

2. Operating environment

The end-use environment for the device should be considerd. It is corrosive? Is dust an issue? Will the lubricant be exposed to water, steam, solvents, or solvent fumes? Is micor-vibration a possibility? Will your component be exposed to in-vacuum conditions that require virtually no outgassing or particle generation?

3. Load conditions

For most applications, the prevention of wear caused by friction is the primary reason for the use of a lubricant. Thus the load at the interface is an obvious concern. In general, higher visosity base oils support heavier loads. If the load in the contact zone is too great or the speed is too slow, asperities on the rubbing surfaces can collide, causing excessive wear. In this situation, which is reffered to as boundary lubrication, extreme pressure (EP) additives may be necessary. Synthetic ester greases are particularly suited for preventing heavily loaded metal-on-metal wear. Under relatively light loading, the high surface energy of a silicone grease may hepl to re-wet the surface.

4. Type of device

Different types of devices can have a wide variety of lubrication requirements. A bearing that supports a rotating shaft will have a lubricant system different than a set of plastic gears. Many specialized lubricants have been developed for specific parts, including ball bearings, journal bearings, stationary electrical connectors, electrical switch contacts, plastic gear trains, lead screws, and cams.

5. Material compatibility

Some lubricants can "attack" certain plastics and elastomers. The base oil can infiltrate the solid material or cause the solid's components to leach into the lubricant. Good design practice tests the compatibility of specific plastic and elastomers by evaluating physichal properties such as tensile strength, dimensional stability, and gravimetric stability after immersion in the lubricant. Higher temperatures and lower base oil viscosity usually exacerbate chemical incompatibility. Certain metals which come on contact with the lubricant may exhibit accelerated corrosion or lead to undesirable polimerization or "varnishing" and failure of the lubricant base oil. These problems can be avoided by identifying early in the design process the metal alloys used in the device and analyzing and testing thier compatibility with the candidate lubricants and additives.

6. Design goals

Lubricant do much more than just prevent wear. Lubricants can also be used to achieve specific design goals. Grease can: control precision motion; reduce noise, vibration, and harshness; eliminate buzz, squeaks, and rattles; reduce torque; reduce temperature

7. Others

Budget for lubricant? any rquirements of special certifications such as NSF registration, Halal certificate required? How long lubricant need to last (due to in some application re-lubricating or replacing new lubricant is impossible or dificult, such as space or closed gear-box)?

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