Thesis
Effects of Non-Traditional Fixturing Methods on Damage Characteristics Along the Machined Edge, Dimensional Accuracy and Machined Surface Quality in Milling of Plain Weave Carbon Fiber Reinforced Plastics
Washington State University
Master of Science (MS), Washington State University
2023
DOI:
https://doi.org/10.7273/000005201
Abstract
Five-sided machining, referring to machining all four sides and the top surface while fixing the bottom surface, is critical when a CFRP plate is needed to be machined without changing fixtures. It is essential when accessibility to workpiece is crucial and to achieve high precision and low defect during the process. This thesis investigates the effect of fixture techniques and machining parameters (feed rate, fiber orientation) on the damage characteristics, dimensional accuracy, and surface roughness when slot-milling a woven bi-directional CFRP. Two fixturing methods, namely ice and adhesive tape fixtures have been used. The slot milling experiments were conducted to make rough slots at three different depth of cuts (2 mm, 3 mm, 4 mm) on the CFRP coupons at constant 6000 rpm spindle speed. 1.27 mm wide finish cut on both sides of slot were performed with climb and conventional milling. These three operations were conducted at three feed conditions which are 152.4 mm/min, 304.8 mm/min, and 609.6 mm/min utilizing a two-flute solid carbide endmill of 6.35 mm diameter. Two feed directions, 0°/90° and 45°/135° of carbon fiber orientations, were used to investigate the effect of fixture techniques, fiber orientations and feed rates on the milling experiment outputs, which include cutting forces, damage depth, machined slot width, and surface roughness. The specific cutting force and specific cutting energy in the ice fixture condition are larger on average than that in the adhesive tape fixture, primarily due to increase in stiffness. Damage such as delamination was observed to be minimum at low feed rate in ice fixture when conventional milling is used. Average delamination depth increases with increasing feed, irrespective of fiber orientation and fixture technique. Regardless of the milling conditions, the slot width was undersized than the programmed width. The larger feed condition produces smaller width, hence larger variation from the desired dimension. Surface roughness shows an inverse relation with specific cutting energy; resulting in a better surface when specific cutting energy is higher. Although the cutting force in ice fixture was higher, it was found to produce better geometry in terms of delamination, dimensional accuracy, and surface roughness.
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Details
- Title
- Effects of Non-Traditional Fixturing Methods on Damage Characteristics Along the Machined Edge, Dimensional Accuracy and Machined Surface Quality in Milling of Plain Weave Carbon Fiber Reinforced Plastics
- Creators
- Nazia Binte Rouf
- Contributors
- Dave Kim (Advisor)Stephen Solovitz (Committee Member)Chao Qin (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Engineering and Computer Science (VANC), School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 119
- Identifiers
- 99901019936801842
- Language
- English
- Resource Type
- Thesis