Date of Award

12-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

Committee Member

Dr. Gregory Mocko, Committee Chair

Committee Member

Dr. Scott Mason

Committee Member

Dr. Georges Fadel

Abstract

The objective of this research is to demonstrate the role of physical and virtual prototyping in product design. The product development process that was used as a case study for this research was a piece of equipment that improves the ability to capture accurate dimensions of extruder bores of diameter ranging from 39.69 mm to 92.08 mm and depth ranging from 96.52 cm to 327.66 cm. The motivation is that the Eastman Chemical Company expressed difficulty capturing accurate measurements of circularity, diameter, and runout throughout the depth of their polymer extruders because conventional technology is cumbersome at significant depths and low clearances. Additionally, use of manual technology, such as a traditional bore gauge can capture dimensions, but not changes through depth, such as runout. However, by capturing a three dimensional representation of the bore, runout can be visualized. In order to build a 3D model of the bore, measurements must be take along the sidewalls at various depths in three dimensional space.

After spending time in the field at Eastman with the Digital Reproduction team identifying a need, understanding the current process and analyzing the equipment they have on hand, ideation began. By analyzing other scenarios that require observation with tight clearances, such as pipe inspection and medical applications, it was determined that parts and pieces of the technology needed to capture such 3D measurements already exist, but have never been applied in polymer manufacturing maintenance. These products were used as benchmarks during ideation. A design architecture was developed through iterative ideation, brainstorming, and multiple methods of prototyping, a solution was created. In iii order to create a 3D model of the inside of an extruder bore, a Faro Ion laser tracker was coupled with a rover that could positon the Faro ball strategically throughout the bore. To place the ball where it was needed, a device was designed that has capability of moving in and out of the bore, and oscillating the ball 360 degrees.

Then, during a site visit to watch a bore being inspected using their current measuring process, additional requirements were identified. After this, a plethora of virtual prototypes yielded five rapid prototypes. Though ideation yielded parallel concepts, all 3D modeled iterations were built on the same premise of using existing Faro technology to place a ball against the bore walls, and all designs relied on a microcontroller to position the ball. However, the physical design of the rover changed extensively as virtual and physical models generated new requirements and led to design refinements.

During the course of this study, it became clear that phases of iterative design are non-linear. Brainstorming is a process that takes place throughout iterative prototyping, thus, the process is circular. Also, modeling method selection is not a progressive process. One may be tempted to think that ideas would lead to sketches, sketches would lead to virtual models, and virtual models would yield tangible models, but this is not the case. The process is iterative, and each subsystem will likely be at a different level of refinement from other subsystems at every iterative design phase, and the goal of each prototype will be unique to each subsystem.

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