Session: 03-04-03: Advanced Machining and Finishing Processes

Paper Number: 114338

114338 - Electropolishing (EP), ChemPolishing (CP), and As-Built Additively Manufactured Metal Components for Electroless Nickel Plating Research 

Center for Nanotechnology Research and Education, Mechanical Engineering, University of the District of Columbia, Washington DC-20008, USA

The current study investigates electroless nickel plating and surface finishing techniques such as ChemPolishing (CP) and ElectroPolishing (EP) for postprocessing on additively manufactured stainless-steel samples. Existing additive manufacturing (AM) technologies generate metal components with a rough surface that typically exhibit fatigue characteristics, resulting in component failure and undesirable friction coefficients on the printed part. Small cracks formed in rough surfaces at high surface roughness regions act as a stress raiser or crack nucleation site. As a result, the direct use of as-produced parts is limited, and smoothening the Surface presents a challenge. Previous research has shown that CP ChemPolishing has a significant advantage in producing uniform, smooth surfaces regardless of size or part geometry. EP Electropolishing has a high material removal rate and an excellent surface finishing capability. Electropolishing, on the other hand, has some limitations in terms of uniformity and repeatability. On additively manufactured stainless-steel samples, electroless nickel deposition has a higher plating potential. Nickel has excellent wear resistance, and nickel-plated samples are more robust as scratch resistant than unplated samples when tested for scratch resistance. Extra corrosion resistance is provided by the high phosphorus electroless nickel solution. The study uses electroless nickel solutions to investigate nickel deposition on EP ElectroPolishing, CP ChemPolishing, and as-built AM components. Electroless nickel plating is a chemical process that deposits an even layer of nickel-phosphorus alloy on the substrate's Surface without using an electrical current. This treatment was created to increase the hardness and surface resistance of manufactured components to the harsh environment. This research uses medium-phosphorus (6-9% P) and high-phosphorus (10-13% P). The L9 Taguchi design of experiments (DOE) was used to optimize the electroless nickel deposition experiments, which include the prosperous content in the solution, surface preparation, sample geometry plane orientation, and Nickel strike exposition time. The mechanical properties of as-built and nickel-coated additive manufacturing (AM) samples were investigated using a standard 5 N scratch test and adhesion testing using the ASTM B-733 thermal shock method. The KEYENCE Digital Microscope VHX-7000 and Phenom XL Desktop SEM were used to examine the pre- and post-processed surfaces of the AM parts. The complete scratch and Design of Experiment (DOE) analysis was performed using the Qualitek-4 software. According to the experimental results, the Electropolishing method reduces surface roughness by 63.8%. In the roughness measurements, the Arithmetic Average Roughness or the absolute average relative to the base length Ra value was reduced from 16.81µm to 6.09 µm. The absolute average Ra value for the as-built sample, on the other hand, is approximately 16.81 µm, which decreases to 10.52 µm after the ChemPolishing process. It represents a 37.41% reduction in surface roughness. The Electroless Nickel Plating process performed achieved excellent adhesion of the layer since the coating was examined for blistering or other evidence of poor adhesion and did not find any evidence of it. The Qualitek-4  Ra result analysis determined that the optimum condition for roughness improvements will reach at Nickel Strike 60 seconds-level 3, Surface Preparation Chem Polishing-level 1, Orientation YZ-level 2, Phosphorus level Medium-level 1. Likewise, the optimum condition for nickel deposition layer thickness will be reached at Nickel Strike 60 seconds-level 3, Surface Preparation ElectroPolishing-level 1, Orientation YZ-level 2, Phosphorus level Medium-level 1. When compared to as-built samples, nickel-coated AM samples were up to 62 percent more scratch resistant. According to the findings of this research, electroless nickel plating is a reliable, viable option for surface hardening and finishing AM components in a wide range of applications. This work is in progress concerning testing the optimum conditions, completing measurements, and analyzing the results.

Keywords: Taguchi design of experiments, additive manufacturing chem polishing, electropolish, electroless nickel plating, hardness, crack nucleation.

 

 

 

Presenting Author: Pablo E. Sanchez Guerrero University of the District of Columbia

Presenting Author Biography: I am a multidisciplinary professional in Civil Engineering and in Industrial Engineering. I have a Master’s degree in Civil Engineering and a Master’s degree in Water Resources Management. I earned my first engineering degree in Industrial Engineering from the University National Experimental del Táchira, San Cristóbal, Táchira State, Venezuela, in 1987. Afterward, I have worked as an Industrial Engineer for more than twenty years in production, maintenance, operation standardization, planning and control of projects, and a number of related disciplines in the food, plastic, hydroelectric power, automotive, construction, and agriculture industries. I have gained extensive experience in traditional manufacturing methods, including primary manufacturing processes: casting (injection-molding), forming (forging, rolling, extrusion), joining (welding, soldering, fastening, epoxying), and secondary manufacturing processes: machining (turning machines and boring mills), shapers and planers, drilling machines, milling machines, grinding machines, power saws, presses and surface working, such as heat treatments and thin coatings.

I moved to the United States in 2009. I graduated in Civil Engineering from the University of the District of Columbia, Washington DC, U.S.A. in 2014. I worked as an intern in D.C. Water during the summers of 2013 and 2014. Following my internship, I worked as a Field Engineer for Whiting-Turner Contracting Company & Gilford Corporation for the M.G.M National Harbor Grand Casino Project, which was more than a 1 Billion Dollar project at the Prince George County, Maryland.

Since November 01, 2015, I am working as a Laboratory Engineer at the School of Engineering and Applied Sciences of the University of the District of Columbia, Washington DC. I graduated in the Professional Science master's in water resources management in Fall 2018 and a Master of Science in Civil Engineering in Spring 2021. As a Laboratory Engineer, I have worked in the EOSINT M280 Metal 3D Printer Site Preparation, Installation, and start-up jointly with the E.O.S. field Engineer. I currently assist students in operation and maintenance of the printer. Likewise, I have been supporting faculty and students in the COVID-19 face shield rapid prototype production for a community project/donation to D.C. Government (3D plastic printing), SEAS Senior Capstone Projects in the machine shop, executing the restoration and start-up of the C.N.C. (Computer Numerical Control) Milling Machine GANESH GBM-2616, and teaching laboratory classes of Geotechnical Engineering, Concrete, Hydrology and Hydraulics, ThermoFluid, Solid Mechanics, and Structure. I have been working diligently in:

1. Special Competitions such as Student Steel Bridge Competition during 2016 (first-time U.D.C. historical participation in the competition), 2017, 2018 (U.D.C. historical accomplishment in the competition getting Second (2nd) Place in the Virginia Conference), and 2019.
2. N.A.S.A. Human Exploration Rover Challenge 2018 (2nd place among the all-rookie teams, and the 7th place overall out of 100 national and international University teams), 2019, and 2020.
3. The Revolutionary Aerospace System Concepts Academic linkage RASC-AL Special Edition Challenge 2019.
4. Assembling and starting up Rethink Robotics Sawyer, a high-performance collaborative robot for Mechatronics Laboratory.
5. Setting up Ambulatory Suspension System (Navigator) and Vicon Motion Capture System for Bio-Engineering and Bio-Medical Research Laboratory.
6. The Establishment of new equipment for Renewable Energy Laboratory known as Smart Grid Solar and Wind Power Generation Trainer Apparatus (WE 210), including the experimentation on Electrolysis of Hydrogen and Oxygen (hydrogen energy cells), Solar energy (photovoltaic cells), Wind energy modulus, and intelligent grid.

My research interests are computer science and engineering, including Advanced Manufacturing, Nanofabrication, and Biomedical engineering tied to human mobility and prosthetics. What motivates my research interests is the quality of life improving capability of these disciplines and my deep desire and passion for becoming an advanced-level multidisciplinary expert in these disciplines. As an experienced Industrial Engineer, I would like to explore and get expertise in Advanced Manufacturing processes and Nanotechnology-Nanofabrication. These disciplines incorporate innovative technologies to improve products and processes and have a wide range of applications in other disciplines such as Civil Engineering, Industrial Engineering, and Biomedical Engineering. The opportunity to investigate 3D Medical Applications of prosthetics for veterans with blast injuries or amputees excites encourages me to serve our veteran heroes.

I strongly believe in work ethics, technical skills, integrity, honesty, sincerity, discipline, methodology, teamwork, hard work, and determination to achieve all the required objectives. I possess excellent interpersonal skills to establish and maintain positive working relationships. I am a quick learner and flexible to adapt to any new technical scenario.

Authors:

Pablo E. Sanchez Guerrero University of the District of Columbia
Pawan Tyagi University of the District of Columbia