Operations Management
4. Tutorial: Chapter 4 – Process Design – Blanks
Exercise 1: Process flow analysis of the robot arm production
Robotec Inc. produces the robot arms in 4 production steps. These production steps are “Cut-
ting” of metal sheets, “Welding” of the parts into arms, “Painting” and “Packaging” of the
arms. Three different parts (middle part and right and lef side part) are cut all in once. Four
metal sheets are put ontop of each other. The three parts are cut then in one process step
(twelve parts are the results of this cut). Five of 200 cuts are faulty and all parts of this cut are
not usable. Welding of three parts creates 1% waste. Painting accounts for 0.5% waste.
Calculate how many cuts have to be performed, so that (at least) 1200 faultless robot arms can
be produced.
, 2
Exercise 2: M/M/1-Queues – Packaging Process
RobotTec Inc. Uses robots to package spare parts into bins. The robot is able with its suction
head to pack eight spare parts every 15 seconds. The packing time underlies an exponential
distribution. The planner of the packaging station have estimated that on average 24 spare
parts are arriving per minute at the packing station following a Poisson distribution.
a) How many spare parts would be waiting on average at the packaging station?
b) In fact, 30 spare parts are waiting at the packaging station. Therefore, the arrival rate is
larger. What is the real arrival rate?
c) The planner propose changing the suction head. The new suction head is able to pack
eight spare parts every ten seconds. How many spare parts will be in the queue with this
suction head? (Please use the realistic arrival rate from task 2b))
4. Tutorial: Chapter 4 – Process Design – Blanks
Exercise 1: Process flow analysis of the robot arm production
Robotec Inc. produces the robot arms in 4 production steps. These production steps are “Cut-
ting” of metal sheets, “Welding” of the parts into arms, “Painting” and “Packaging” of the
arms. Three different parts (middle part and right and lef side part) are cut all in once. Four
metal sheets are put ontop of each other. The three parts are cut then in one process step
(twelve parts are the results of this cut). Five of 200 cuts are faulty and all parts of this cut are
not usable. Welding of three parts creates 1% waste. Painting accounts for 0.5% waste.
Calculate how many cuts have to be performed, so that (at least) 1200 faultless robot arms can
be produced.
, 2
Exercise 2: M/M/1-Queues – Packaging Process
RobotTec Inc. Uses robots to package spare parts into bins. The robot is able with its suction
head to pack eight spare parts every 15 seconds. The packing time underlies an exponential
distribution. The planner of the packaging station have estimated that on average 24 spare
parts are arriving per minute at the packing station following a Poisson distribution.
a) How many spare parts would be waiting on average at the packaging station?
b) In fact, 30 spare parts are waiting at the packaging station. Therefore, the arrival rate is
larger. What is the real arrival rate?
c) The planner propose changing the suction head. The new suction head is able to pack
eight spare parts every ten seconds. How many spare parts will be in the queue with this
suction head? (Please use the realistic arrival rate from task 2b))
