College - Author 1
College of Engineering
Department - Author 1
Mechanical Engineering Department
Degree Name - Author 1
BS in Mechanical Engineering
College - Author 2
College of Engineering
Department - Author 2
Mechanical Engineering Department
Degree - Author 2
BS in Mechanical Engineering
College - Author 3
College of Engineering
Department - Author 3
Mechanical Engineering Department
Degree - Author 3
BS in Mechanical Engineering
College - Author 4
College of Engineering
Department - Author 4
Mechanical Engineering Department
Degree - Author 4
BS in Mechanical Engineering
Date
3-2018
Primary Advisor
John Fabijanic, College of Engineering, Mechanical Engineering Department
Abstract/Summary
The purpose of this study is to determine the best method for manufacturing a part with precision tolerances and a small deflection requirement. The desired tolerances include a flatness of 0.002in, parallelism of 0.005in, heat tolerance of 60℃, and a max deflection at the loaded end of the part of 0.28mm. To accomplish this, our team uses carbon fiber as the part material because compared to traditional metals it is stiffer and lighter. Carbon fiber molding processes are explored and narrowed down to Liquid Composite Molding (LCM) and Resin Transfer Molding (RTM). These processes use dry fiber combined with epoxy resin, rather than pre-impregnated carbon fiber, for ease of resin control and the ability to control fiber to resin ratio. The fiber orientation used for this process are unidirectional carbon fiber and carbon fiber weave. Unidirectional carbon fiber alone is best for minimizing deflection, however it is only stiff in one direction and will have large deflection if twisted. Carbon fiber manufacturing processes and corresponding safety procedures are also explored. It was decided that it is better to design a mold that included all part components, rather than trying to machine and potentially disrupt the carbon fiber after.
To determine the superior molding method, aluminum square testing coupons were developed and tested for both LCM and RTM methods. For RTM, resin did not properly saturate the coupons and led to a brittle and unsatisfactory part. The LCM method led to fully saturated parts and adequate results after a few attempts were made. The team chose to proceed with the LCM method for molding the final more complex part. The final part dimensions and two-dimensional mock-up, provided by our sponsor, were translated into an online modeling program and outsourced for mold machining. From the final mold we made parts using LCM with two different fiber layups. One layup was two layers of unidirectional fiber, followed by four layers of weave, and finished with two layers of unidirectional fiber for a total of eight resin infused layers. The second layup was one layer of fiber weave, followed by two layers of unidirectional, then two layers of weave, two layers of unidirectional, and a final layer of weave for a total of eight resin infused layers. We recommend using the first layup to minimize deflection.
URL: https://digitalcommons.calpoly.edu/mesp/414