· Load:
Type: Is it a thrust load (along the screw axis)? A radial load? Or a torque load?
Size: What is the maximum load? (Newtons or kilograms-force (kgf))
Direction: Is the load direction constant? Is it bidirectional?
Variation: Is the load constant, fluctuating, or impactful?
Point of application: Where does the load act on the nut? (This affects the additional torque.)
· Motion Profile:
Stroke: The total distance the nut needs to move (mm or m).
Speed: The maximum required speed (m/min or mm/s) and typical speed.
Acceleration/Deceleration: The maximum acceleration/deceleration of the system (m/s²).
Duty Cycle: What is the ratio of duty cycle to rest cycle? (Affects temperature rise and lifespan)
·Accuracy Requirements:
Positioning Accuracy: The ability to repeatedly reach the target position (micrometers).
Repeatability: The consistency of reaching the same point multiple times (micrometers).
Travel Parallelism/Runout: The deviation in the nut’s travel path.
Backlash: The axial clearance between the screw and nut (micrometers). High-precision applications often require preloading the nut to eliminate backlash.
·Life Expectancy:
What is the expected service life in hours or kilometers? (Usually calculated based on L10 lifespan)
Installation Space:
The maximum allowable screw length and diameter.
Nut dimensions.
Space for the bearing support.
·Environmental Conditions:
Temperature range (affects material, lubrication, and thermal expansion).
Contaminants such as dust, debris, liquids, and chemicals.
Vibration and shock.
·Budget:
Lead screw prices vary significantly depending on accuracy, preload level, brand, and material.