Matching viscosity alone is not enough
Grease behavior depends on its base oil, thickener, additives and consistency. Products with a similar appearance or nominal viscosity can behave differently in low-temperature torque, plastic interaction, scattering, evaporation, noise and tactile feel. Start by defining the operating conditions and pass/fail criteria.
Six inputs to define first
| Materials | Resin grade, metal, rubber, surface treatment and mating material |
|---|---|
| Temperature | Start-up, steady-state, ambient and temperature cycling |
| Load & speed | Contact pressure, rotation or sliding speed, frequency and stroke |
| Motion quality | Torque, noise, tactile feel, damping and scattering |
| Manufacturing | Amount, application method, assembly, cleaning and storage |
| Life & compliance | Expected life, environment, target markets and required documents |
Specify the material, not just “plastic”
Include the resin grade, fillers, molding conditions, residual stress and mating material. Long contact under stress may reveal changes that a quick appearance check does not.
Define temperature limits
Cold start may be dominated by torque, while high-temperature service raises questions around evaporation and separation. Part temperature can differ from ambient temperature.
Set measurable test targets
Quiet, light, heavy or controlled movement can be reframed as torque, sound, return time and temperature-dependent change.
Confirm with actual materials and hardware
Published data narrows the candidates. Validate the amount, clearance, surface state and assembly variation in representative hardware, both initially and after life testing.