Principle
25. Self Service
a. Make the object service itself and carry out supplementary
and repair operations
b. Make use out of waste of material and energy
- Principle Description: Perform related functions or operations in conjunction with or concurrent with, the primary function or operation.
- Hints on Usage: A system’s primary function can be utilized or tapped for self-service or for ancillary service. Self-service works on two levels: 1) the primary function, 2) the related or concurrent function.
- In many cases, the self-service is a function of a natural control mechanism such as a candle wick. The candle wick provides the base material for starting the flame (primary function) and also provides a wicking of additional wax to sustain the flame. These forms of self-service are a result of physical, chemical or geometric effects.
- In other cases, the self-service is a function of a measurement or detection process followed by a feedback process to correct for a system need or deficiency. This overlaps with Principle 23, Feedback.
- This principle may also prove useful in systems that facilitate self-service for people. In this case, the system is static — in a waiting mode — until someone has a need and decides to fulfill that need.
Comments: Sometimes it is difficult to distinguish self-service
from feedback. Actually, self-service assumes some feedback, but without a
special “feedback system.” For example, if we need a valve that
lets dry steam out, but does not allow water or wet steam out, then we could
use some material (such as wood) that expands when wet, and contracts when
dry.