Perhaps the most obvious is to increase precision, which really is a function of manufacturing and assembly tolerances, gear tooth 
surface finish, and the guts distance of the tooth mesh. Sound can be suffering from gear and housing components and also lubricants. In general, expect to spend more for quieter, smoother gears.
Don’t make the error of over-specifying the engine. Remember, the input pinion on the planetary should be able manage the motor’s result torque. low backlash gearbox What’s more, if you’re utilizing a multi-stage gearhead, the result stage must be strong enough to soak up the developed torque. Certainly, using a better motor than required will require a bigger and more expensive gearhead.
Consider current limiting to safely impose limitations on gearbox size. With servomotors, output torque can be a linear function of current. Therefore besides protecting the gearbox, current limiting also protects the electric motor and drive by clipping peak torque, which can be anywhere from 2.5 to 3.5 times continuous torque.
In each planetary stage, five gears are simultaneously in mesh. Although you can’t really totally remove noise from such an assembly, there are several ways to reduce it.
As an ancillary benefit, the geometry of planetaries fits the shape of electric motors. Therefore the gearhead could be close in diameter to the servomotor, with the result shaft in-line.
Highly rigid (servo grade) gearheads are usually more expensive 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 seen as a mechanical springtime. The torsional deflection caused by the spring action adds to backlash, compounding the effects of free shaft movement.
Servo-grade gearheads incorporate several construction features to minimize torsional stress and deflection. Among the more common are large diameter output shafts and beefed up support for satellite-gear shafts. Stiff or “rigid” gearheads have a tendency to be the most costly of planetaries.
The type of bearings supporting the output shaft depends on the load. High radial or axial loads usually necessitate rolling element bearings. Small planetaries could get by with low-price sleeve bearings or various other economical types with relatively low axial and radial load capability. For bigger and servo-grade gearheads, heavy duty output shaft bearings are usually required.
Like the majority of gears, planetaries make noise. And the faster they run, the louder they get.
Low-backlash planetary gears are also obtainable in lower ratios. While some types of gears are generally limited by about 50:1 and up, planetary gearheads lengthen from 3:1 (solitary stage) to 175:1 or more, depending on the amount of stages.