Statiscal Process Control
Essay by meAnn Caldejon • August 17, 2015 • Coursework • 335 Words (2 Pages) • 1,347 Views
Homework Chap 3 & 13
- Construct a [pic 1]-chart for this process using [pic 2]limits and describe the variation in the process.
P = total defectives/ total sample observation
= 307/20 (100)
=0.1535
UCL = 0.1535 + 2 [sqrt of (0.1535 (.85)]/100]
=0.22
LCL = 0.1535 – 2 [sqrt of (0.1535 (.85)]/100]
= 0.081
[pic 3]
This diagram suggests that process is out of control. The proportion of defectives is increasing. The root cause should be investigated.
- Construct a [pic 4]-chart using [pic 5]limits for this process and indicate if the process was out of control at any time.
C = 86/20 = 4.3
UCL= 4.3 +3 (sqrt4.3) = 12.9
LCL = 4.3-3(sqrt4.3) = - 1.92
[pic 6][pic 7][pic 8]
The sample observations are within control limits. It suggests that the quality measures are effective, thus it only needs continuous monitoring to ensure quality standards.
Problem 13-06.
- Optimal production run quantity (Q)
2 (700) (6000)
-------------------
9 ( 1 - 19.29/116)
= sqrt [ 42000000 / 7.47 ]
=749
- Total annual inventory costs
CoD/Q + (Cc*Q)/2
=700 / 749 + (9*749)/2
= 3371
- Optimal number of production runs per year
= D/Q
= 6000/749
= 8 runs per year
- Optimal cycle time (time between run starts)
= 311 days / (D/Q)
= 39 days
e. Run length in working days.
= Q/p
= 749/116
= 6 days
Problem 13-20.
Southwood needs 715 containers each year. It costs $1200 to hold a container at its distribution center, and it costs $6000 to receive an order for the containers.
Determine the optimal order size, minimum total annual inventory cost, number of annual orders, and time between orders.
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