40 Inventive Principles
The analysis of several thousand patents led to the conclusion that
inventive tasks and technical contradictions from all kinds of industrial
branches could be solved by a limited number of basic principles (techniques).
Modern TRIZ contains 40 basic Inventive Principles. Here are some examples:
11. Principle of the “safety cushion in advance” (preventative measure).
18. Principle of the utilization of mechanical vibration.
22. Principle of the conversion of harmful influences into beneficial ones.
27. Principle of disposability (using of cheap shortlivings objects).
28. Replacement of the mechanical system.
35. Transformation of the physical and chemical properties.
Contradiction Table
The application of these
principles takes place in a matrix called a Contradiction Table with 39
lines and 39 columns (see Fig. 3). The 39 engineering input parameters are
the most important characteristics of technical systems:
• Mass, length, volume.
• Reliability.
• Speed.
• Temperature.
• Waste (loss) of material.
• Accuracy of measurement.
• Accuracy of manufacturing.
• Convenience of use; etc.
These parameters appear in the table as the properties of a technical
contradiction and help to formulate a technical contradiction in a system in
standardized terms, for example:
• Speed vs. Reliability
• Mass vs. Strength
• Temperature vs. Accuracy of measurement etc.
As a result of the analysis of the many hundred thousand patents the table
shows the inventive principles which are most likely to resolve the
formulated technical contradiction. Even though not all of the cells of the
Contradiction Table are filled in, it still gives solution principles for
more than 1200 types of technical contradictions, substantially reducing the
scope of the search to only the most appropriate solution concepts.
Example "SpeedReliability"
At speeds of over 60mph, the risk
of serious car accidents due to a tyre damage is greatly increased. This
already formulates a technical contradiction and can directly be put into
the table: increasing the speed of the vehicle (row 9) has a negative
influence on the reliability of its running gear (column 27). Looking up the
intersection of row 9 and column 27 (table cell 9/27), we find the following
solutions in the following order of priority: 11, 35, 27, 28 (see
illustration). According to principle 11, the insufficient reliability is to
be compensated for by the preinstallation of damage prevention equipment. A
possible solution would be to fix a steel disk behind each rim, which in the
case of a tyre damage, keeps the car in a level position, thus reducing the
risk of a serious accident (US Pat. 2879821).
Another example of the principle no. 11 “safety cushion in advance” is to be
found in the pharmaceutical industry. Sleeping pills are covered with a thin
film of an emetic substance. If more than the prescribed number of pills is
swallowed at one time, the concentration of the emetic substance reaches a
threshold value in the stomach, which then provokes vomiting.
Magic of Contradiction Matrix
Holding no less power of
attraction is the Contradiction Matrix, as a method of using the 40
principles. As known, the Matrix  as a result of about 7 years of
investigation work – delivers an approach on how to select the best
principles to resolve one specific technical contradiction, in order to
reduce the trialanderror work involved in applying all 40 principles.
In spite of the fact that in TRIZ cradle  Russia even in the 1980’s the
Matrix was no longer the most recommended of strong TRIZ tools, a lot of
attempts to improve this empirical and early TRIZ method are still known
nowadays:
• Adding/reducing the number of lines or columns,
• Changing the titles of 39 technical parameters,
• Updating the matrix cells or filling the «empty» matrix cells,
• «Customising» matrix: The user can reinvent the matrix according their
experience,
• Other mathematical experiments, up to random choice of matrix cells etc.
Although such attempts are being undertaken with the best intentions, they
do not contribute to TRIZ significantly, neither practically nor
theoretically. Also, the best and fullest matrix would not guarantee the
solution of difficult problem. Not the Matrix but the Principles are crucial
for problem solving. They are good to enhance technical creativity but only
scratch the surface of the problem in complicated situations.
In practice one should warn all newcomers to TRIZ about «blind trust» to the
Matrix. One can remember the earlier experience of using the matrix in
Russia, still in printed form: the pointer often unintentionally hit the
false matrix cell, but nevertheless it did work.
For the matrixfans we recommend hence formulating several contradictions
for one problem situation, forming a set of recommended principles and as
the next step using those principles which were recommended more than once.
The correct application of the matrix in this case gives a small number of
principles, which were recommended 3…8 times (e.g. principles N.35  8 times;
N.5  5 times, N.19  3 times etc.), and a longer «tail» of principles which
were recommended only once. In any case this approach helps to understand
and to document the bundle of underlying technical contradictions in the
system that may be of high importance for problem analysis.
It is also possible to apply the
principles according to their general, statistical frequency of use. In our
experience, the first 10 principles from this list produce workable
solutions to approx. 50% of all problems.
List of the 40 Inventive
Principles ordered in their statistical frequency of use:
35. Transformation of the physical and chemical properties
10. Prior action
1. Segmentation
28. Replacement of the mechanical system
2. Extraction
15. Dynamism
19. Periodic action
18 Mechanical vibration
32. Changing colour
13. Inversion
The contradiction matrix today belongs to the history of TRIZ. We
recommend that all users keep their own usage statistics and add their own
examples and subprinciples to the list of the 40 inventive principles.
