Eventos Anais de eventos
COBEF 2023
12th Brazilian Congress on Manufacturing Engineering
EFFECT OF MICROSTRUCTURE ON MICROMILLING OF POWDER-BED-FUSED INCONEL 718
Submission Author:
Wayne Nguyen Phu Hung , Texas , United States
Co-Authors:
Jacob Southern, JAMES HYDER, Jacob Galle, Wayne Nguyen Phu Hung
Presenter: Wayne Nguyen Phu Hung
doi://10.26678/ABCM.COBEF2023.COF23-0572
Abstract
This paper studied micromilling of powder-bed-fused Inconel 718. Two scanning strategies (checkerboard, stripe), three cutting speeds (10, 14, 19 m/min), three chip loads (0.8, 1.0, 1.2 μm/tooth), and two tool coating (AlTiN/Si3N4, AlTiN) were selected for micromilling in minimum quantity lubrication with Ø0.5mm flat-end milling cutters. Both surface finish and width of micromilled slots were measured using a 3D digital microscope to determine the machinability of as-printed samples. Scanning electron microscopy and energy dispersive X-ray were used to examine the machined surface and identified different phases that may affect the machining process. Metallic carbide particles were formed due to fast cooling rate at the edges or corners of an Inconel block. Such hard particles damaged the fragile cutting edges and their thin coating layers, accelerated tool wear, and reduced the machined slot widths. After impact with a tool cutting edge, a carbide particle was either sheared off, shattered, or uprooted to smear on the machined surface along the tool path. The measured surface finish data were 100 times higher than theoretical values. Aggressive machining parameters using high cutting speed and /or chip load affected tool wear and reduced the slot width about 15 μm after 100 mm milling distance. The checkerboard scanning strategy, produced more consistent microstructure with even carbide particle distribution, resulted in more consistent surface finish and slot width data.
Keywords
Inconel 718, Additive manufacturing, micromilling, tool wear, Intermetallic carbide, Surface finish
