Process capability of milling and lathe operation

1. Process Capability Analysis of Face
Milling Operation

2. Group Members
15-IE-10
15-IE-14
15-IE-16
15-IE-32

3. Contents:
• Introduction
• Problem Statement:
• Methodology
• Statistical Analysis
• Result and discussion
• Conclusion

4. Introduction:
• Heavy Mechanical Complex Ltd (HMC) is a
Pakistani state-owned defense manufacturer, a
subsidiary of State Engineering Corporation
(SEC), Ministry of Industries & Production and
Government of Pakistan. It is located
in Taxila, Rawalpindi, Pakistan.

5. Problem Statement:
• To Analyze the behavior of milling process has been
employed to produce 25 rectangle piece of mild steel
(MS). The thickness of each specimen is 11.5mm. We
have to reduce the thickness of each specimen to 9.5+0.1
by Face Milling Operation to Analyze the Process
Capability of that Operation.

6. Methodology
• Estimation of Process Capability for facing operation
involves the following steps:
•  Understanding the basic concepts of process capability
analysis and its measures.
•  Process data collection.
•  Calculate required statistics
•  Validate the critical assumptions.
•  Estimation of Cp, Cpl.

7. Statistical Analysis
• Process capability study is a method of combining the
statistical tools developed from the normal curve and
control charts with good engineering judgment to
interpret and analyze the data representing a process.
• The purpose of the process capability study is to
determine the variation spread and to find the effect of
time on both the average and the spread.
• The administration, analysis and use of the process
capability study should be an integral part of the quality
engineering function. The results could be used for new
design applications, inspection planning and evaluation
techniques.

8. Product description:
Material: Mild steel Name : Rectangle plate
Operation: Facing Specifications: 9.5± 0.1
Instrument used : Vernier
calliper
All dimensions are in “
mm”

9. Milling Machine
• Milling is the process
of machining using
rotary cutters to remove material
by advancing a cutter into a
work piece. This may be done
varying direction on one or
several axes, cutter head speed,
and pressure. Milling covers a
wide variety of different
operations and machines, on
scales from small individual
parts to large, heavy-duty gang
milling operations.

10. Solving on Minitab:
I-Chart:
• Control limits for I- Chart
• Mean value X = 9.5264
• UCL = X +A2R
• UCL = 9.5264+.153(.35)
• UCL = 9.58
• LCL = X-A2R
• LCL = 9.5264 - .153(.35)
• LCL = 9.47

11. Cutting Tool
• Tungsten Carbide Tool

12. Machine Parameters
Speed 315 RPM
Feed 0.33mm
Depth of Cut 0.25mm

13. Data collection
9.60 9.65 9.30 9.50 9.55
9.50 9.60 9.55 9.50 9.45
9.45 9.60 9.52 9.56 9.50
9.55 9.51 9.52 9.49 9.51
9.62 9.48 9.56 9.49 9.50

14. I-Chart:

15. Histogram chart

16. Results and Discussion:
CP = 6sigma
• CP = 6(0.089)
• CP = 0.534
• Sigma = R/d2
• Sigma = 0.35 / 3.931
• Sigma = 0.089
• Capability index = UCL-LCL / 6 sigma
• CPI = 9.58-9.47 / 0.089
• CPI=1.23
• CPI = 1.23>1 Process capability index
Sigma level= 3.7

17. CPI
CPI>1 Best
Solution
CPI<1 Not
acceptable
CPI =1 Ok

18. Conclusion:
• The study was conducted to examined using Cp, CpI
index, to show the importance of process capability
analysis. With the help of statistical tools like control
charts, histogram and normal probability plot and run
chart using the statistical softwareMinitb-14. It will used
to construct the confidence interval of CpI, as it is
significantly influenced by sample size, sample size of
25 observations is used for the process capability study

19. Thank
you