DiGiannoSurface

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Jan 9, 2024

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Mechanical Engineering Laboratory New Jersey Institute of Technology Report Submitted by Michael F. DiGianno Experiment No. 5 Date Performed 10/10/23 Date Submitted 10/17/23 Course & Section ME215-101 Instructor Naruemon Suwattananont Surface Texture Experiment Title Performed by Group 101b With TA Md Sojib Kaisar Group Members Michael D Bauly S Yahia Elmanier Marta D Stephen M Jonathan G Braeden G

Table of Contents Abstract 3 Introduction 3 Objectives 3 Background and importance 3 Procedure 4 Original Data Sheet 5 Results and Calculations 6 Discussion 12 Conclusion 12 Questions and Answers 13 Appendix A 14 2

Abstract This is the lab report for experiment five, known as the surface texture lab. This lab is designed to introduce students to surface topography which is a term that refers to the profile and overall roughness of a surface. Students will also become familiar with some machines used to measure surfaces such as a surfometer and perthometer. They will measure samples provided and record the roughness of the surfaces. This helps build an understanding of both surface topography and which are more accurate and reliable for measurement. Introduction Surface measurement is an important area to understand when we discuss various machining and measurement techniques. It will allow us to analyze how different machines, machining methods, and tool selections impact the final product. This lab will allow students to interpret which methods help them accomplish this best. Objectives Students participating in this lab should be able to develop an understanding of surface finishes. They will be introduced to several machines that will help them understand and measure the roughness of the surface. These machines will help students understand what types of operations such as milling and lathe turning create what finishes. Background Surface topography is a very wide field. Its importance spreads beyond our area of discussion. “Surfaces represent an important tool for the description and analysis of a multitude of phenomena related to the social, economic, natural and technical sciences.” (Wolf 2020). Procedure In this lab students were asked to take the surface roughness measurements of various samples with different machines and techniques. The samples consisted of samples produced in the previous labs, as well as non metallic samples provided. The machines were demonstrated to the group. The machines consisted of a perthometer, surfometer, and a microfinish comparator. The students then replicated the measurements made by the ta. One of the samples was to be placed in the vibratory finisher, and ran for forty-five minutes. In the meantime, students drew pictures of the samples, and converted units. Once finished, they took measurements of the refinished sample. 3

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Original Data Sheet 4

Results and Calculations Perthometer: Lathe sample cut #1 Perthometer: Lathe sample cut #2 6

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Perthometer: Lathe sample cut #3 Perthometer: Lathe sample cut #4 7

Perthometer: Clear block (rougher side) Perthometer: Pre-vibratory finishing 50ipm 8

Perthometer: Pre-vibratory finishing 25ipm Perthometer: Pre-vibratory finishing 10ipm 9

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Perthometer: Vibratory finished piece 50ipm Perthometer: Vibratory finished piece 25ipm 10

Perthometer: Vibratory finished piece 10ipm Discussion To restate, the main objectives of this lab module are to familiarize students with surface measurement and its uses. This includes the machines involved with taking the relevant measurements and how they are interpreted. Students also learn about the vibration finishing machine albeit briefly. From the initial reading, we can draw the conclusion that the faster a machine is running in either RPM or feedrate, the higher the roughness. Although the data is arranged slightly counterintuitively on the data sheet, if you rearrange the numbers to be in order of feed rate or rpms, the trend makes itself clear. The data is currently arranged in order that the cuts appear on the samples, which was easier to keep track of during data collection. The problem starts when we discuss the vibration finishing of the cnc sample. After the vibratory finish, the sample appeared to become rougher which goes against the purpose of the machine used. For the initial readings, these were largely expected. When running machines at higher speed, you run into a few issues. The first is that there is a large amount of vibration being added into the system. This can be compounded with other factors such as heat warping as well as a large volume of shavings that need to be moved away from the workpiece. The vibratory machine on the other hand produced some unexpected effects. We were expecting the roughness to be brought down, but it instead went up. We believe this is an outlier and not the normal for this type of procedure. 11

All of the readings derived from the microcomparitor are very flawed. I’ll be the first to admit that it’s very hard to use. We did our best, but the readings were definitely off due to human error. Professor gave some specific instructions when it came to cleaning the cnc sample after its vibratory finishing. When it was finished, it was taken out of the room and we were not privy to the cleaning process. I believe this is what caused the strange spike in roughness. Many machines use a liquid with small particles of solid dispersed in them to remove material. This is how for instance water jets cut. If the vibratory finisher uses this same technique to smooth out parts of the piece, an improper cleaning would indeed create a rougher surface with leftover particulate on the piece. Conclusion In conclusion, we now have a better understanding of the roughness readings that come from a surfometer and a perthometer, and why they are superior to a hand microcomparitor. The results paint us a clear picture of how running machines at higher speeds create rougher surfaces. The vibration data doesn't seem reliable and it wouldn’t be a good idea to draw conclusions from it. Through analysis of our data, and error evaluation we can take away important lessons about surface measurement. Questions and Answers 1. Turning and grinding operations change the microstructure of the metals, by creating heat within the surface of the workpiece. This makes smoother finished have a higher fatigue strength. 2. A) depending on the operation roughes varies from 6-125μin B) Depending on the purpose of the seal it can range from 0.2-3.2 μm 3. Yes, this is possible through the use of an electron microscope. 4. It means to lay angular in both directions. 5. Yes, the desired finish is possible with both operations. 6. If two light beams are used for measurement, a reading can be made with their displacement. 7. As previously stated electron microscopes as well as the machines used in this lab. Surface micro comparator, surfometer, and perthometer accomplish the job. 8. Vibrational finishing should decrease surface roughness, using particles to smooth small ridges, our data unfortunately does not support this. 12

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9. It seems that the higher the feed rate and/or RPM, the rougher the surface. 10. A) No, its not consistent B) One could snap, saw, or heat roll to name a few C) 0.25μm D) Sources may include heat warping and vibration 11. Boring, chemical milling, drilling, electron beam, forging, laser, milling, sawing, shaping, turning. Appendix A. Wolf, G. W. (2020). Surfaces—topography and topology. Surface Topography: Metrology and Properties , 8 (1), 014003. https://doi.org/10.1088/2051-672x/ab70e8 13