Instrumentation & Measurement: Calibration of Straightness and Flatness Laboratory Report
Contents
1. Summary 1
2. Introduction 1-3
1.1 Least Squares Method 2 1.1.1 Method 2 1.2 Minimum Zone Method 3
2. Objectives 3
3. Apparatus 3-4
4. Procedure 4
5. Results 4-7
5.1 Straightness 4-6 5.2 Flatness 7
6. Discussion 8-10
6.1 Straightness 8 6.2 Flatness 8-9 6.3 Closing error 9-10
7. Conclusion 10
8. References 10
9. Appendices 11-15
9.1 Appendix A-Procedure 11-13 9.2 Appendix B-Certificates of calibration 14-15
1. Summary
The aim of this experiment was to examine three methods for determining the straightness and flatness of a horizontal granite surface. The first method was manual and the other two (Least Squares method and Minimum Zone method) were analysed by the computer, after a set of data was inputted. The main equipment used in the experiment was the granite surface, the ''Talyvel'' electronic level, the PC and the software (SURFSURE). After obtaining a number of results and analyzing them it was deduced that the computer analysis was more accurate than the manual calibration. It also produced post-processed data that could be printed and analyzed further.
2. Introduction
Calibration is a method by which the straightness and flatness of a surface can be determined (within specified tolerances) and hence taken into account. There are many applications where the calibration of straightness and flatness of surfaces is crucial (e.g. high precision surfaces). Possible examples could be the surface bed of a milling machine and lathe-bed guide ways. Straightness is defined as ''A condition in which an element of a surface or an axis is a straight line''. Flatness is said to exist if the following conditions are satisfied: 1) ''all generators (lines) must be straight'' and/or 2) ''all generators (lines) must lie in the same plane''.
[pic]
Fig. 2.1 A surface, all of whose generators (lines) parallel to the sides are straight, but which is not flat
There are several ways with which the straightness and flatness of a
1. Summary 1
2. Introduction 1-3
1.1 Least Squares Method 2 1.1.1 Method 2 1.2 Minimum Zone Method 3
2. Objectives 3
3. Apparatus 3-4
4. Procedure 4
5. Results 4-7
5.1 Straightness 4-6 5.2 Flatness 7
6. Discussion 8-10
6.1 Straightness 8 6.2 Flatness 8-9 6.3 Closing error 9-10
7. Conclusion 10
8. References 10
9. Appendices 11-15
9.1 Appendix A-Procedure 11-13 9.2 Appendix B-Certificates of calibration 14-15
1. Summary
The aim of this experiment was to examine three methods for determining the straightness and flatness of a horizontal granite surface. The first method was manual and the other two (Least Squares method and Minimum Zone method) were analysed by the computer, after a set of data was inputted. The main equipment used in the experiment was the granite surface, the ''Talyvel'' electronic level, the PC and the software (SURFSURE). After obtaining a number of results and analyzing them it was deduced that the computer analysis was more accurate than the manual calibration. It also produced post-processed data that could be printed and analyzed further.
2. Introduction
Calibration is a method by which the straightness and flatness of a surface can be determined (within specified tolerances) and hence taken into account. There are many applications where the calibration of straightness and flatness of surfaces is crucial (e.g. high precision surfaces). Possible examples could be the surface bed of a milling machine and lathe-bed guide ways. Straightness is defined as ''A condition in which an element of a surface or an axis is a straight line''. Flatness is said to exist if the following conditions are satisfied: 1) ''all generators (lines) must be straight'' and/or 2) ''all generators (lines) must lie in the same plane''.
[pic]
Fig. 2.1 A surface, all of whose generators (lines) parallel to the sides are straight, but which is not flat
There are several ways with which the straightness and flatness of a
References: ▪ http://www.coe.uncc.edu/~jraja/megr6181/pdf/Flatness_Straightness.pdf ▪ http://www.weibull.com/AccelTestWeb/least_squares_method.htm ▪ Nitin Maheshwari, A Thesis “On the Selection of CMM based Inspection Methodology for Circularity Toleran”, Division of Research and Advanced Studies of the University of Cincinnati (2001) 9. Appendices 9.1 Appendix A-Procedure 9.2 Appendix B-Certificates of calibration