Chapter 17
Q. 17.1
Parts Delivery System in Automatic Assembly
The cycle time for a given assembly work head = 6 sec. The parts feeder has a feed rate of 50 components per min. The probability that a given component fed by the feeder will pass through the selector is θ = 0.25. The number of parts in the feed track corresponding to the low-level sensor is n_{f 1} = 6 . The capacity of the feed track is n_{f 2} = 18 parts. Determine (a) how long it will take for the supply of parts in the feed track to go from n_{f 2} to n_{f1} , and (b) how long it will take on average for the supply of parts to go from n_{f 1} to n_{f 2}.
Step-by-Step
Verified Solution
(a) T_{c} = 6 sec = 0.1 min. The rate of depletion of parts in the feed track starting from n_{f 2} will be R_{c} = 1/0.1 = 10[/latex parts/min
Time to deplete feed track (\text{time to go from} n_{f 2} to n_{f 1}) = T_{de} = \frac{18-6}{10}= 1.2 min
(b) The rate of parts increase in the feed track when the low-level sensor is reached is fθ – R_{c} = (50)(0.25) – 10 = 12.5 – 10 = 2.5 parts/min
Time to replenish feed track(\text{time go from} n_{f 1} to n_{f 2}) = T_{re} = \frac{18-6}{2.5}= 4.8 min