How would you define the cycle time for a material
How would you define the cycle time for a material
would you define the cycle time for a material handling system.? What are the
b) What is the traffic factor ?
How it effects to material handling systems?
What is the worker efficiency in a material
handling systems? Why it is important?
What are the decision variables in a material
handling system and how are they related to demand that the system isserving?
The chart below indicates the material
movements between departments in a batch production environment. The distances
in meters and load frequencies are given as # of times per day time. AGVs
(Automated guided vehicles) are used to transport materials between
departments. They move at an average speed = 175 ft/min (loaded) and 250 ft/min
(empty). Loading time per delivery is 2 min, unloading time is 1 min, and
anticipated traffic factor = 0.90. Use an availability factor = 95%. Determine
the number of trucks required under each of the followingassumptions:
a) The AGVs never travelempty
The AGVs travel empty a distance equal to their
In a facility, in order to deliver pallet loads
of parts between work cells, 8 forklift trucks are used. Average travel
distance loaded is 520 ft and the travel distance empty is 410 ft. The trucks
are driven at an average speed of 440 ft/min when loaded and 616 ft/min when
empty. The load handling time is 2 min and the unload handling time is 1 min.
If the traffic factor for the system is 0.85, worker efficiency is 0.95 and
availability is 100%, what is the maximum hourly delivery rate of the 8
An AGVShas an averageloaded
travel distanceper delivery620 ft. The average empty traveldistance is not known.Required numberof deliveries per
hour50. Load and unload timesare
each 0.5 minand the AGVspeed = 130 ft/min. Anticipatedtraffic factor
= TF and availability= AF. Developan equation that relatesthe number
of vehicles requiredto operatethe system as a functionof the averageempty traveldistanceLe.
along the line on workpallets
(one productper pallet).At the final workstationthe finished products
are removedfrom the pallets. The pallets
are then removedfrom the
line and deliveredback to the front
ofthe linefor reuse. Automated
guided vehiclesare usedto transportthepalletstothefrontoftheline,adistanceof600ft.Returntripdistance
the line is also 600 ft.Each AGVcarries five pallets and travelsat a speed of 145 ft/min(either loaded or empty).The palletsform queuesat
each end of the line,so that neitherthe productionlinenortheAGVsareeverstarved
15 sec; timeto releasea loaded AGVand movean
empty AGVinto positionfor loadingat the end of the line
= 12 sec. The same timesapply
for pallet handlingand release/positioningat the unload station locatedat the front of the productionline. Assumethe traffic factoris 1.0 since therouteisasimpleloop.Howmanyvehicles
the demand level faced by the company marketing department andproduction planning department stated that the required production rate is 80
units/hr for acertain product. It
is planned to have an assembly work content time of 2 hr of directmanual labor. It is to be produced on a
production line that includes fiveautomated
workstations. The remaining manual stations will each have one worker. It isexpected that 9% of the cycle time will be
lost due to repositioning at the bottleneck station.If the balance delay
(1 â Balance Efficiency) is expected to be0.05.
Determine the cycletime
c) Determine the number ofworkers
d) Determine the number of
workstations needed for theline.
An automotive assembly plant in Bursa is
expecting to have a demand for thenew model that can be satisfied by a capacity of
320800 units annually. The plantwill
operate 52 wk/yr, 2 shifts/day, 5 day/wk and 8 hr/shift. Itwill be divided intothree departments: (1) body shop, (2)
paint shop, (3) trim-chassis-final department.
The body shop uses robotic arms
for welding operations while the paint shop coatsthe bodies using static electric painting. Both of these
departments are highlyautomated.
Trim-chassis-final has no automation: There are 19 hr of direct labor content
oneach ear in this third department,
where cars are moved by a continuousconveyor.
Determine hourly production rate of theplant
Determine number of workers and workstations
required in trim-chassis-final ifno automated stations are used. The average
manning level (average number oflabor
per workstation) is 3, balancing efficiency is 95%, and a repositioning time of0.1 min is allowed for eachworker.
A moving belt line is used for a product whose
work content time = 35min. Production rate = 52 units/hr The length of
each station = 1.90 m, and manning levelis
1. Itis expected that the
balance delay will be about 0.12 or slightly higher.Uptime reliability = 98%. Time lost for repositioning each
cycle is 6sec.
Determine the number of stations needed on theline.
If the tolerance time were 1.5 times the cycle
time, determine the belt speedand
spacing between parts fur thisline.
A manual assembly line is to be designed to
make a small consumer product.The
work elements, their times, and precedence constraints are given in the tablebelow. The workers will operate the line
for 400 min / day and must produce 300 product
/ day. A mechanized belt moving at a speed of 1.25 m/min will transport
theproducts between stations. Because of the variability in the time required
operations, it has been determined that the tolerance time should be1.5 times the cycle time of theline.
Determine the ideal minimum number of workers
c) Use the Kilbridge and Wester
method to balance theline.
d) Compute the balance delay for
your solution in part(b).
e) Determine the spacing between
assemblies on theconveyor.
Determine the required length of each workstation
to meet the specificationsfor the
Solve the above problem with Ranked positional
weight method and updateyour
Now suppose element 5 has a cycle time of 2
minutes and can not be brokendown
into smaller pieces. Offer a solution to this problem and solve problem 4 withyour newapproach.