Surface Topography Lab PDF

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Summary

Professor Samardzic...

Description

1

MECHANICAL ENGINEERING LABORATORY NEW JERSEY INSTITUTE OF TECHNOLOGY

Report Submitted by

Emily Carvalho

Date Performed

3/5/20

Course & Section

ME215-004

Experiment No.

Date Submitted Instructor

3/30/20 Professor Samardzic

SURFACE TOPOGRAPHY

Performed by Group

Group Members

001A

With TA

Paul Mamauag Mohamed Diab Kai Cha Ramazan Uku

Keven

5

2

TABLE OF CONTENTS Abstract

3

Introduction

3

Procedure

3

Original Data Sheet

4

Results and Calculations

5

Discussion

8

Conclusion

8

Questions and Answers

8

References

10

3

Abstract This laboratory is focused on becoming familiar with surface finishes. The purpose of the lab was to learn the standards for specifying measurements and understanding the influences different finishes have on engineering applications. We learned how to operate the perthometer and the surfometer. Then, we were given 5 samples to measure surface roughness of using the machines and determine which machining processes would have resulted in the values measured. The result of this lab was an understanding of how to measure surface finishes with different tools and a use of a surfometer and a perthometer.

Introduction In the mid-1900’s people realized that the ability to measure surface texture also gave them the ability to analyze the processes that made it, which led to surface topography gaining popularity (Nugent, 2011). This laboratory exposed students to the procedures in surface topography of different materials. The main objectives of this lab were to 1) learn how to use the perthometer and surfometer, 2) learn the standard symbols used to specify surface roughness, and 3) learn the different manufacturing processes that produce variations in surface finishes. This lab is extremely important because engineers must be able to factor in surface finishes of materials in order to accurately use them for their intended functions.

Procedure 1. Study the different surface roughness from different manufacturing processes in Table 51 2. Learn different methods to measure surface roughness 3. Learn the principles of the perthometer 4. Learn how to operate the perthometer 5. Learn the principles of the surfometer 6. Learn how to operate the surfometer

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7. Measure the surface roughness of the 5 samples given using the perthometer and the surfometer and record it in the data table 8. Determine which machining processes could have resulted in the values measured. 9. Draw the samples using standard method to represent surface finishes

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Original Data Sheet

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Results and Calculations Perthometer - Metal Plate:

Perthometer - Plastic Plate:

Perthometer - Shaft 1:

7

Perthometer - Shaft 2:

Perthometer - Shaft 3:

8

Surfometer - All materials:

Discussion This laboratory was extremely informative on understanding how to operate different methods of conventional surface measurements. We were exposed to how the process is

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completed, and the influence that manufacturing processes have on resulting surface roughness. We learned how to use the perthometer and the surfometer. To do this, we had to have an understanding of the material we were given so we could properly complete the lab. To reiterate, the main objectives of this lab were to 1) learn how to use the perthometer and surfometer, 2) learn the standard symbols used to specify surface roughness, and 3) learn the different manufacturing processes that produce variations in surface finishes. We accomplished this when we measured the surface roughness of a metal plate, a plastic plate, and 3 different shafts. There were no calculations in this lab but there may have been errors in the measurements of the surface roughness of the samples because of inconsistencies in the surface of the material. Due to COVID-19 we were unable to use the microfinish comparator because it requires the operator to physically touch the part and compare it’s “feel” to the microfinish comparator to make an educated judgement.

Conclusion In conclusion, the lab was successful in providing us with the knowledge of the different manufacturing processes and processes of how to measure surface roughness. We were then able to apply this by using 5 different samples to measure the surface of and guess which manufacturing processes could have been responsible. The purpose of this lab was to familiarize students with the standard methods in which surface measurements are recorded and written. We accomplished all our objectives and worked cohesively as a group to test 5 samples.

Questions and Answers 1. What kind of commercial instruments are available for measuring and recording the surface finish? Commercial instruments available include sufometers, perthometers, and microfinish comparators. 2. Discuss the effects of grinding and turning on the endurance limit of steel. What is

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the reason for the change in fatigue strength with various surface finishes? The effects of grinding and turning on the endurance limit of steel lowers it because of the heat generated in the process (Tricard, 1994) 3. Explain the principle of measurement by light wave interference? Light wave interference works by analyzing the pattern of interference when two different light beams are used and measurements can be taken from the displacement. 4. Why is the microfinish comparator often used for specifying surface finish? The comparator is used when the material has the appearance of common machined surfaces and it is inexpensive and easy to use. 5. A designer places the following surface finish specification symbol on a given surface: 10 0.030 10.002 a. Is the roughness width cut off consistent with the roughness width? No it is not consistent b. What processes would be needed to achieve the surface roughness specified? To achieve a surface roughness of 10, snapping, sawing, shaping, sand casting, or hot rolling would be the processes you would need. c. What would the roughness be in metric measurement?

√

10 µin

10-6 in

0.0254 m

1 µm

1 µin

1 in

10-6 m

= 0.254 µm d. What may be the cause of the waviness? The cause of the waviness could have been a result of the manufacturing process used 6. Is it possible to observe the surface roughness directly through an optical or scanning electron microscope? Yes it is possible to observe the surface roughness directly through an optical or scanning electron microscope 7. What does this symbol mean? √ ❑ This symbol means “Lay angular in both directions” 8. Is it possible to obtain surface roughness Ra = 1.6 µm by any of the two manufacturing processes: grinding & boring? Yes, both grinding and boring can create a surface roughness of 1.6 µm 9. List all the available machining processes to obtain the microroughness in a range of 3-5 µm. Sawing, Shaping, Drilling, Chemical Milling, Milling, Electron Beam, Laser, BoringTurning, and Forging 10. What is the typical surface roughness requirement for the following engineering components? a. gear teeth: 0.4 µm b. bearing seals: 0.2-0.8 µm

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References Tricard, Marc (1994). Residual Effects of Finishing Methods. In ASM Handbook (Vol. 5), 144-151. https://doi.org/10.31399/asm.hb.v05.a0001238 Nugent, P. (2011). 50 Years of Quality: A Superficial History of Surface Finish. Retrieved from https://www.qualitymag.com/articles/87804-50-years-of-quality-a-superficialhistory-of-surface-finish...