Event Title
Utilization of Design of Experiment Techniques in Reducing a Glass Grinding Defect
Location
Hager-Lubbers Exhibition Hall
Description
PURPOSE: Gentex Corporation is developing a new style of interior rear-view mirror where the substrate sits proud of the mirror housing. Federal regulations require at least a 2.5 mm radius of curvature around the perimeter of the substrate, and a grinding operation has been determined to form the radius in the substrate. During the process development, scratches have been observed along the surface of the ground edge. The purpose of this study was to utilize design of experiment (DOE) techniques to determine the process parameters that most significantly affected the presence of the scratches. METHODS: Feed rate, tool speed, and tool rotational direction were tested using a 23 full factorial design with two replicates. A vertical CNC and a diamond abrasive tool were used to form the ground edge into the substrate. Surface scratches on the ground surface were measured using an optical microscope. ANALYSES: Analysis of variance (ANOVA) was used to analyze the data from the study. The response variable was the number of scratches present on a ground substrate. RESULTS: Using a significance level of α = 0.05, the only significant factor that affected the presence of the surface scratches was the tool rotational direction with a p-value of 0.013. It was determined that up-grinding produced less surface scratches than down-grinding. There were no significant interactions between factors. CONCLUSIONS: Results indicated that tool rotational direction significantly affected the number of surface scratches on a substrate, and the feed rate and tool speed were insignificant. To reduce the occurrence of the surface scratches, up-grinding should be employed.
Utilization of Design of Experiment Techniques in Reducing a Glass Grinding Defect
Hager-Lubbers Exhibition Hall
PURPOSE: Gentex Corporation is developing a new style of interior rear-view mirror where the substrate sits proud of the mirror housing. Federal regulations require at least a 2.5 mm radius of curvature around the perimeter of the substrate, and a grinding operation has been determined to form the radius in the substrate. During the process development, scratches have been observed along the surface of the ground edge. The purpose of this study was to utilize design of experiment (DOE) techniques to determine the process parameters that most significantly affected the presence of the scratches. METHODS: Feed rate, tool speed, and tool rotational direction were tested using a 23 full factorial design with two replicates. A vertical CNC and a diamond abrasive tool were used to form the ground edge into the substrate. Surface scratches on the ground surface were measured using an optical microscope. ANALYSES: Analysis of variance (ANOVA) was used to analyze the data from the study. The response variable was the number of scratches present on a ground substrate. RESULTS: Using a significance level of α = 0.05, the only significant factor that affected the presence of the surface scratches was the tool rotational direction with a p-value of 0.013. It was determined that up-grinding produced less surface scratches than down-grinding. There were no significant interactions between factors. CONCLUSIONS: Results indicated that tool rotational direction significantly affected the number of surface scratches on a substrate, and the feed rate and tool speed were insignificant. To reduce the occurrence of the surface scratches, up-grinding should be employed.