This research had two objectives. First, to examine the
possible superiority of any of the three principal MTM systems
for the derivation of time standards, recognizing the natural
variability of actual work times arising from unpaced operator
performance. Then, to consider whether the use of further
simplifications of predetermined motion time systems, which may be
derived from MTM, might permit equally acceptable time standards
to be obtained.
Factory studies were used to compare the standards predicted
by MTM-1, 2 and 3 against actual performance by well trained.
workers. No significant difference was detected between the times
predicted by MTM-1, MTM-2 and MTM-3.
Four simplified systems were developed from the factory data
and, except for the system in which motion cases were ignored,
no statistically significant\differences were found between cycle
times predicted by these systems and by the general levels of
Times for similar operations in the same factory as the original
sample were determined using MTM-1, MTM-2, MTM-3 and two simplified
systems. The results were equally acceptable by each of these
five systems. Further testing based upon maintenance type work
data did not show a satisfactory transferability of simplified
systems into this entirely different working environment.
The study did not support the widely held view that there are
minimum cycle times below which MTM-2 and MTM-3 should not be used to
establish a time standard.
In considering the variability of the actual work times, it
was not possible to account for the individual effects of factors
which create variability of operators performing unpaced tasks.
Nevertheless, a representative distribution for this variability
was estimated, in which the variability of the operator work-time
was related to the average cycle time.
Mechanical, Electrical and Manufacturing Engineering