1. Statistical Analysis of CNC Slots Confidence Interval Graph representing depth vs length Discussion

2. CNC Slots

3. 95% Confidence Interval for CNC Slots Nominal Depth (thousandths of an inch) Confidence IntervalSample MeanSample Std Deviation 11.528 ≤ μ ≤ 1.605y= 1.567S= 0.0500 22.729 ≤ μ ≤ 2.849y= 2.789S= 0.0782 33.833 ≤ μ ≤ 3.967y= 3.900S= 0.0866 44.973 ≤ μ ≤ 5.161y= 5.067S= 0.1225 56.246 ≤ μ ≤ 6.354y= 6.300S= 0.0707 67.240 ≤ μ ≤ 7.472y= 7.356S= 0.1509 78.151 ≤ μ ≤ 8.493y= 8.322S= 0.2224 89.200 ≤ μ ≤ 9.489y= 9.344S= 0.1878 910.285 ≤ μ ≤ 10.560y= 10.422S= 0.1787 1011.195 ≤ μ ≤ 11.472y= 11.333S= 0.1803 Overall Variance1.075 ≤ μ ≤ 1.205y= 1.14S= 0.312

4. Discussion Overall the CNC was off by 1.14 thousandths of an inch Depths were pretty consistent within our range of 1 to 6 thousandths of an inch Depths of 6 to 10 thousandths of an inch had greater variation throughout the cut Possible reasons: – Increased bending force on bit due to cutting more material in one sweep – May need a slower cutting speed on deeper depths

5. Statistical Analysis of Dremel on Stewart-MacDonald Base Confidence intervals Graphs representing depth vs. length of cut Conclusions

6. Dremel Cutting a Slot

7. 95% Confidence Interval on Overall Performance for Dremel Slots End Mill BrandConfidence IntervalSample MeanSample Std Deviation Accrupro0.259 ≤ μ ≤ 1.314y= 0.787S= 0.952 Atrax0.312 ≤ μ ≤ 1.395y= 0.853S= 0.978 OSG0.708 ≤ μ ≤ 1.092y= 0.900S= 0.346

8. Discussion Overall Accrupro end mill was closer to the nominal value, but it had greater variations in the depth. End mill needs to have less variation throughout the cut. Data suggests that the OSG end mill is more consistent throughout the cut. Need to work on accuracy Possible reasons for error: – CNC Slots were not at the correct depth – Depth adjustment was done visually using the CNC slots – Dremel Base nuts became loose through the cut – Inconsistent downward force on Dremel while cutting – Travel speed of Dremel was not adequate – Surface variations on plate could have given inaccurate measurements

9. Dremel Cutting a ‘S’ line

10. 95% Confidence Interval on Overall Performance for Dremel ‘S’ Line End Mill BrandConfidence IntervalSample MeanSample Std Deviation Accrupro0.615 ≤ μ ≤ 1.465y= 1.040S= 0.768 Atrax0.504 ≤ μ ≤ 1.003y= 0.753S= 0.450 OSG0.404 ≤ μ ≤ 0.850y= 0.627S= 0.403

11. Discussion Overall the OSG end mill was closer to the nominal value and had the less variation in the depth Need to work on accuracy Possible reasons for error: – CNC Slots were not at the correct depth – Depth adjustment was done visually using the CNC slots – Dremel Base nuts became loose through the cut – Inconsistent downward force on Dremel while cutting – An additional force is added to the bit to do the curved lines – Travel speed of Dremel was not adequate – Surface variations on plate could have given inaccurate measurements