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littlefield cocoahuff paper 1

Littlefield Simulation #1 Write Up
Team: CocoaHuff
Nick Freeth, Emanuel Martinez, Sean Hannan, Hsiang-yun
Yang, Peihsin Liao
1. How did you forecast future demand?
We tried to get our bottleneck rate before the simulation while we only had limited information. By getting the bottleneck rate we are able to
predict which of the station may reach full utilization ahead of others and therefore needed more machines to cover the extra load of work to
keep the utilization high but not at the peak of 100%.
2. How did you use your demand forecast to determine how many machines to buy?
We have first calculated the bottleneck rate for each station before the simulation started. We have calculated the process rate using
the formula given, with one machines on each station, and the average expected utilization rate, we have gotten the answer that the
bottleneck will be the first station. And the station with the fastest process rate is station two. We have bought one machine at the
beginning of the simulation for station one since it’s the bottleneck, then we have observed the other two stations, but they all didn’t
seem like their utilization went up a lot on the first few days, so we didn’t purchase any machines for station two and three at the start.
3. How did you decide when to purchase your machines?
We have decided to purchase the machines when the plot utilization rate shows that the utilization of the station is going to 100%. We
didn’t purchase the machines immediately after the utilization rate went to 100%., instead, we have done some observation. We have
waited for a few days, and if the utilization rate kept staying at 100%, we then purchase the machine for that station.
4. If you sold any machines, how did you decide when and how many?
Yes, we sold one machine at station 1. We decided to sell this machine towards the end as we realized a couple of teams surpassed us
by jumping about $10,000. So we decided to sell this one machine at station 1 when its utilization was dropping. We sold the machine
on one of the last days at what we thought would be about its low point. This seemed like the right time to sell a machine because the
$10,000 would catapult us from about 9th or 10th place into 6th place. Selling one machine was the right amount for us because
selling any more than that would have ended up costing us money and time. Selling even two machines would have cost us too much
because we would not have had enough machines left to fulfill all our future orders.
5. If you changed the queue sequencing rule, why; and what did you learn?
We have changed the sequencing rule on day 94 because we didn’t really know what was going to happen if we change the sequence,
but we have quickly came to realize that the lead time of our product have rose. Which caused our revenue to go down, so we have
changed the sequence back to FIFO on day 98. We have decided to change the sequence to priority for station four again on day 112.
And we have observed that when there is same queueing kits on station 2, for example on day 107 and day 114, we have realized that
the utilization rate of station 2 have gone up, and the lead time for each product have decreased. So we have decided to keep the
sequence as priority to step 4.
6. In hindsight, what should you have done differently?
In hindsight, we should have bought our machines at Station 1 and Station 3 as early as possible. Of course, in the heat of the moment
and not knowing demand, we weren’t sure if we needed 3 machines at Station 1 and 2 machines at Station 3. However, if we had
bought the extra machines earlier than we did, in the long run, we would have made more money. This is because at the points when
we allowed utilization to reach 100% at these stations, we lost money because we did not have enough machines. If we had 3
machines at Station 1 and 2 at Station 3 as soon as possible, utilization would not have reached 100% and we would not have lost
money. We could have tried to experiment to switch the priority to station 2 earlier, and observe for longer and see that is going to
happen then switching back immediately after we realized the revenue is decreasing.
- "History" (the list of changes you made during the simulation)