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What is cycle time
how long it takes to produce a part, from the start of the process, the end of the process, beginning of next process
what is lead time?
how long it takes for a part to get thru a process from start to end, including all operations and wait times involved in the process
available work time / pcs per day demand = min or secs
Takt time equation
is a catalog of elemental time standards from a database collected over years of motion and time study
Standard data
Time standard/ Plant Rate(R value) =
Machines required
the time required to produce a part to meet customer demand, based on the work time available and customer demand during the same time period
Takt Time defintion
Production rate in Pcs/hr
(3600 sec/hr)/(cycle time in sec/pc)
the station on an assembly line which has the most work, and therefore the operator is 100% utilized, also the limiting station
Bottle neck station (usually the same as cycle time)
(cycle time * number of operators)/ 3600sec/hr
Manhours per pc equation
sum of all cycle times/ takt time
manpower required
efficiency equation equals
earned time (Standard time * number of pcs produced)/ actual time (hrs)
a combination of product size and cycle time
Converyor speed
work sampling
the rpcessof randomly observing people working to determine how they spend their time
in an elemental ratio study
The element with the smallest percentage will be used to determine the number of observations required
Accuracy measures
the closeness of the ratio to the true ratio of the element normally +or- 5%
Confidence level refers to
how confident we are in the resulting ratios from the study usually 95%
N = # of observations
Z= confidence level plus 1.01, ex. 1.96= 95%
P = percent of total time that an operator spends on one element of work, use the smallest ratio
A= desired accuracy
PF&D Allowances
Personal, Fatigue, and Delay
units of work that are usually indivisible and can be measured on a stopwatch
Elements
Normal pace
effective rate of performance of a conscientious, fully trained, qualified employee
Normal time
the amount of time a operator working at a comfortable pace would take to make a part
Performace factor =
Fundamental motion time/ observed average time
Normal time =
Standard time =
Avg time * %rating
Normal time * Allowances
production labor that can be reasonably and consistently related directly to a unit of work being manufactured
Direct labor
Indirect labor is
all other labor, not directly related to the production of a unit
Material handling, Quality, warehousing, receiving