Perhaps the most low backlash gearbox obvious is to improve 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 as well as lubricants. In general, expect to pay out more for quieter, smoother gears.
Don’t make the error of over-specifying the motor. Remember, the input pinion on the planetary should be able handle the motor’s output torque. Also, if you’re utilizing a multi-stage gearhead, the result stage should 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, result torque is a linear function of current. So besides safeguarding the gearbox, current limiting also defends the engine 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 concurrently in mesh. Although you can’t really totally get rid of noise from this assembly, there are several ways to reduce it.

As an ancillary benefit, the geometry of planetaries matches the form 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 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 seen as a mechanical spring. The torsional deflection resulting from the spring action increases backlash, compounding the effects of free shaft motion.
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 have a tendency to be the costliest of planetaries.
The kind of bearings supporting the output shaft depends on the strain. High radial or axial loads usually necessitate rolling element bearings. Small planetaries can often get by with low-price sleeve bearings or various other economical types with relatively low axial and radial load capability. For larger and servo-grade gearheads, durable output shaft bearings are usually required.
Like most gears, planetaries make sound. And the faster they run, the louder they obtain.

Low-backlash planetary gears are also available in lower ratios. Although some types of gears are usually limited to about 50:1 and up, planetary gearheads lengthen from 3:1 (single stage) to 175:1 or more, depending on the number of stages.