REU Projects for Summer 2006
The following are summaries of the research projects conducted during the 2006 Metrology REU, adapted from submissions by REU participants.
Form Tolerance Inspection to Predict Manufacturing Process Errors
A variety of inspection equipment exists in industry to capture the points on a surface that will envisage manufacturing errors. Manufacturing inspection faces a problem that involves using an optimal method to capture an evenly spread distribution of points on the surface. Sampling does not yield complete information about a surface. Three new methods have been developed in order to improve existing methods using the coordinate measuring machine (CMM), which are the Spiral, Hamspi, and Pie sampling methods. The Spiral method focuses on the center of the area and uses the Archimedean spiral. Hamspi is a method that combines both the spiral and randomized Hammersley to measure points in the middle as well as the bottom of the workpiece. The Pie method combines the random sampling method with the Aligned Systematic sampling method. Mathematical comparisons of these methods have been made to establish credibility. An experiment was performed to determine the accuracy of these models using two dependent variables: inspection time and minimum zone. Regarding the minimum zone the only two factors that were statistically significant were sample size and workpiece shape. For the time, the only two statistically significant factors were sample size, workpiece shape and the interaction between them. This study observed that the beginning and ending cutting zones of spherical surfaces were the most significant regions to verify. It was found that the Spiral and Hamspi methods had similar point distributions as the Hammersley method while placing more emphasis on the origin of the workpiece.
Molecular Dynamics Simulations of Sodium Dodecyl Sulfate Surfactants with Single-Walled Carbon Nanotubes
The purpose of this study was to determine how sodium dodecyl sulfate (SDS) molecules organize on the surface of single-walled carbon nanotubes. Molecular dynamics simulations were employed to create molecular images, animations, density profiles and distribution functions at different temperatures and various amounts of SDS and carbon nanotube in solution. The simulations were conducted at 300, 400 and 500 K for 16, 32 and 64 surfactant systems. The diameter of the nanotube was varied among three sizes: (1) 0.814, (2) 1.63 and (3) 2.71 nm. These values correspond to the (6:6), (12:12) and (20:20) type nanotubes, respectively. The images and plots of the simulations were analyzed to determine if any preferential SDS arrangement existed. Results proved that while SDS organization is random, systems with a higher surfactant concentration exhibited more variation in surfactant structure. Only parallel SDS formations were noted for 16 surfactant systems, whereas both parallel and perpendicular structures were observed for 64 surfactant systems. In addition, it was observed that the SDS molecules were dispersed more uniformly on nanotubes with smaller diameters due to limited surface area. A comparison of images at different temperatures indicated more disorganized SDS structures for systems at higher temperatures. The most likely cause of this observation is due to a high amount of thermal energy for molecules at high temperatures.
Wireless Road Condition Sensors
When drivers are not aware of the conditions of the roads on which they are driving, accidents may occur. They also may occur if they are driving on icy roads that have not been salted or sanded by emergency road crews. A project was begun last summer Dr. Jin-song Pei, a graduate student Nadim Ferzli, and a REU students Oluwaseun Harris and Richard Ivey to address these problems. A sensor-road button (SRB) using three different sensors was manufactured to detect temperature, water, and ice. An algorithm was created, and the sensors were calibrated. A wireless sensor network using Mica2 motes from Crossbow was tested to send this road condition data across a distance. Warnings could then be displayed on roadside dynamic message signs so that drivers will be warned before they see a car in a ditch. Emergency road crews will also be able to respond before an accident happens. This summer, that research was continued by three different REU students. Tests of the wireless network were run and documented, improvements were made to the designs, and the literature review was extended. Tasks were divided among the students, and this paper focuses mainly on the area of literature review.
The Tribology of Lapping
Lapping is a relatively new surface finishing technology that is becoming more widespread throughout industry. It is usually performed after grinding in order to achieve a smoother surface finish. It uses a slurry of small abrasive grains to remove material from the metallic piece being lapped. The slurry is spread over the spinning lapping plate, and the stationary sample is pressed down against it. In general, lapping has not been studied in great depth, and there are many aspects that are not clearly defined.
One factor affecting lapping that has not been studied in depth is the frictional forces acting on the sample during the process. There are frictional forces between the workpiece and the abrasive and between the abrasive and the lapping plate. Both forces will vary with different abrasives, different workpiece materials, different plate velocities, etc. The goal of the first half of this paper is to determine a method of finding these frictional forces that are involved in the lapping process. Two different models of friction and how they can be applied to lapping are presented.
In the second half of the paper, metal lapping was studied and observed in order to make valid recommendations and conclusions with regards to attempting to manufacture flat metal surfaces of a desired thickness, flatness, and surface roughness. This section describes the procedures with which a single-sided loose abrasive lapping process was performed and what observations were made using both aluminum and steel samples on the following parameters: surface roughness, chemical composition, and material removal rate.
The following are summaries of the research projects conducted during the 2006 Metrology REU, adapted from submissions by REU participants.
Form Tolerance Inspection to Predict Manufacturing Process Errors
A variety of inspection equipment exists in industry to capture the points on a surface that will envisage manufacturing errors. Manufacturing inspection faces a problem that involves using an optimal method to capture an evenly spread distribution of points on the surface. Sampling does not yield complete information about a surface. Three new methods have been developed in order to improve existing methods using the coordinate measuring machine (CMM), which are the Spiral, Hamspi, and Pie sampling methods. The Spiral method focuses on the center of the area and uses the Archimedean spiral. Hamspi is a method that combines both the spiral and randomized Hammersley to measure points in the middle as well as the bottom of the workpiece. The Pie method combines the random sampling method with the Aligned Systematic sampling method. Mathematical comparisons of these methods have been made to establish credibility. An experiment was performed to determine the accuracy of these models using two dependent variables: inspection time and minimum zone. Regarding the minimum zone the only two factors that were statistically significant were sample size and workpiece shape. For the time, the only two statistically significant factors were sample size, workpiece shape and the interaction between them. This study observed that the beginning and ending cutting zones of spherical surfaces were the most significant regions to verify. It was found that the Spiral and Hamspi methods had similar point distributions as the Hammersley method while placing more emphasis on the origin of the workpiece.
Molecular Dynamics Simulations of Sodium Dodecyl Sulfate Surfactants with Single-Walled Carbon Nanotubes
The purpose of this study was to determine how sodium dodecyl sulfate (SDS) molecules organize on the surface of single-walled carbon nanotubes. Molecular dynamics simulations were employed to create molecular images, animations, density profiles and distribution functions at different temperatures and various amounts of SDS and carbon nanotube in solution. The simulations were conducted at 300, 400 and 500 K for 16, 32 and 64 surfactant systems. The diameter of the nanotube was varied among three sizes: (1) 0.814, (2) 1.63 and (3) 2.71 nm. These values correspond to the (6:6), (12:12) and (20:20) type nanotubes, respectively. The images and plots of the simulations were analyzed to determine if any preferential SDS arrangement existed. Results proved that while SDS organization is random, systems with a higher surfactant concentration exhibited more variation in surfactant structure. Only parallel SDS formations were noted for 16 surfactant systems, whereas both parallel and perpendicular structures were observed for 64 surfactant systems. In addition, it was observed that the SDS molecules were dispersed more uniformly on nanotubes with smaller diameters due to limited surface area. A comparison of images at different temperatures indicated more disorganized SDS structures for systems at higher temperatures. The most likely cause of this observation is due to a high amount of thermal energy for molecules at high temperatures.
Wireless Road Condition Sensors
When drivers are not aware of the conditions of the roads on which they are driving, accidents may occur. They also may occur if they are driving on icy roads that have not been salted or sanded by emergency road crews. A project was begun last summer Dr. Jin-song Pei, a graduate student Nadim Ferzli, and a REU students Oluwaseun Harris and Richard Ivey to address these problems. A sensor-road button (SRB) using three different sensors was manufactured to detect temperature, water, and ice. An algorithm was created, and the sensors were calibrated. A wireless sensor network using Mica2 motes from Crossbow was tested to send this road condition data across a distance. Warnings could then be displayed on roadside dynamic message signs so that drivers will be warned before they see a car in a ditch. Emergency road crews will also be able to respond before an accident happens. This summer, that research was continued by three different REU students. Tests of the wireless network were run and documented, improvements were made to the designs, and the literature review was extended. Tasks were divided among the students, and this paper focuses mainly on the area of literature review.
The Tribology of Lapping
Lapping is a relatively new surface finishing technology that is becoming more widespread throughout industry. It is usually performed after grinding in order to achieve a smoother surface finish. It uses a slurry of small abrasive grains to remove material from the metallic piece being lapped. The slurry is spread over the spinning lapping plate, and the stationary sample is pressed down against it. In general, lapping has not been studied in great depth, and there are many aspects that are not clearly defined.
One factor affecting lapping that has not been studied in depth is the frictional forces acting on the sample during the process. There are frictional forces between the workpiece and the abrasive and between the abrasive and the lapping plate. Both forces will vary with different abrasives, different workpiece materials, different plate velocities, etc. The goal of the first half of this paper is to determine a method of finding these frictional forces that are involved in the lapping process. Two different models of friction and how they can be applied to lapping are presented.
In the second half of the paper, metal lapping was studied and observed in order to make valid recommendations and conclusions with regards to attempting to manufacture flat metal surfaces of a desired thickness, flatness, and surface roughness. This section describes the procedures with which a single-sided loose abrasive lapping process was performed and what observations were made using both aluminum and steel samples on the following parameters: surface roughness, chemical composition, and material removal rate.
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