Perhaps the most apparent is to low backlash planetary gearbox improve precision, which is a function of manufacturing and assembly tolerances, gear tooth surface finish, and the center distance of the tooth mesh. Sound can be suffering from gear and housing components in addition to lubricants. In general, be prepared to pay more for quieter, smoother gears.
Don’t make the error of over-specifying the engine. Remember, the insight pinion on the planetary should be able deal with the motor’s result torque. What’s more, if you’re using 
a multi-stage gearhead, the result stage must be strong enough to absorb the developed torque. Obviously, using a better motor than required will require a bigger and more expensive gearhead.
Consider current limiting to safely impose limits on gearbox size. With servomotors, output torque is usually a linear function of current. Therefore besides safeguarding the gearbox, current limiting also shields the motor and drive by clipping peak torque, which may be from 2.5 to 3.5 times continuous torque.
In each planetary stage, five gears are concurrently in mesh. Although you can’t really totally eliminate noise from such an assembly, there are many ways to reduce it.
As an ancillary benefit, the geometry of planetaries fits the form of electric motors. Thus the gearhead could be close in diameter to the servomotor, with the result shaft in-line.
Highly rigid (servo grade) gearheads are generally more costly than lighter duty types. However, for rapid acceleration and deceleration, a servo-grade gearhead could be the only wise choice. In such applications, the gearhead may be viewed as a mechanical spring. The torsional deflection resulting from the spring action adds to backlash, compounding the consequences of free shaft movement.
Servo-grade gearheads incorporate a number of construction features to reduce torsional stress and deflection. Among the more prevalent are large diameter result shafts and beefed up support for satellite-equipment shafts. Stiff or “rigid” gearheads tend to be the costliest of planetaries.
The kind of bearings supporting the output shaft depends upon the load. High radial or axial loads generally necessitate rolling component bearings. Small planetaries could get by with low-price sleeve bearings or various other economical types with fairly low axial and radial load ability. For larger and servo-grade gearheads, heavy duty output shaft bearings are usually required.
Like most gears, planetaries make noise. And the faster they run, the louder they obtain.
Low-backlash planetary gears are also obtainable in lower ratios. Although some types of gears are usually limited by about 50:1 or more, planetary gearheads lengthen from 3:1 (solitary stage) to 175:1 or even more, depending on the number of stages.