Production and Operation Management

657 Words3 Pages
Case Study: Hot Spot Plastics Company
0013142陳品翔 0013116廖冠倫 0013148 邱聖凱 0013151 林梓洋

Company introduction: Hot Shot Plastics
Hot Shot Plastics, Inc. filed as an Articles of Incorporation in the State of California and is no longer active. This corporate entity was filed approximately fourteen years ago on Monday, June 05, 2000, according to public records filed with California Secretary of State.
Manufactures processed plastics Plastic cutting machinery, Plastic grinding machinery, Rubber or plastic mills, Rubber or plastic extrusion dies, Plastic injection molds, Thermoforming molds, Ejector pins, In mold decoration IMD cylinder, Blow molding machines, Coating machines, Extruders.

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Exhibit 1 and 2 shows the X̅-chart and R-chart with a plot of all sample means and ranges of the samples. All the points are well within the control limits, although sample 24 is close to the X̅ lower control limit and samples 17 through 22 are above the target.

3. Twelve additional samples of curetimes data from the molding process were collected from an actual production run. The data from these new samples are shown before. Update your control charts and compare the results with the previous data. The X̅- and R-chart are drawn with the new data using the same control limits established before. Comment on what the new charts show.


Exhibit 3 and 4 shows the X̅-chart and R-chart with a plot of all (includes previous and new) sample means and ranges of the samples.
The previous data shows the curetime during the molding process is stable and under control. In contrast, the additional data is out of control, and considerable fluctuation in the data.
In this statistical process control, we set control limits three standard deviations above the mean and three standard deviations below. This mean that 99.7 percent of the sample means are expected to fall within these process control limits. Thus, if one sample falls outside this obviously wide range, we have strong evidence that the process is out of control.
The data from new samples show the present process is out of control
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