Anna Carla Araujo

Force prediction in thread milling

A mechanistic approach for modeling the thread milling process is presented. The mechanics of cutting for thread milling is analyzed as an end milling process with modified cutting edge. The geometry of threads is added to the geometry of the end milling tool to calculate the chip load area. The linear path is simulated and values of the specific energy from end milling are used to compute the cutting forces involved. A comparison between the simulation of the cutting forces for a specific tool in two different situations is made to present the force behavior acquired from the model.

Modeling of the Thread Milling Operation in a Combined Thread/Drilling Operation: Thrilling

This paper investigates a thread making process called thrilling, which performs both drilling and thread milling with one tool. A chip thickness and mechanistic cutting force model has been developed for a thread milling operation with a thrilling tool. The model considers the complex geometry of a thrilling tool and the unique tool paths associated with the thread milling operation. Experiments have been conducted to validate the developed model. Comparison of the average torque and forces between experiment and simulation results shows that the model predicts the experimental results within 12% error.

INFLUÊNCIA DA RECUPERAÇÃO ELÁSTICA NA INTEGRIDADE DE SUPERFÍCIE DO AÇO SUPERDUPLEX

Size effect is an important phenomenon, which occurs during micromilling, and it deals with the relationship between the radius cutting edge, the uncut chip thickness and the microstructure of the workpiece. Super duplex UNS S 32750 is an important steel used in the deep oil industry that could be applied in the fabrication of microsensors and microactuators. However, there are no previous studies on its micromilling: analysis of cutting forces, tool life and integrity of the machined surface. This paper deals with the study of surface roughness and burr formation after micromilling of superduplex stainless steel, considering different levels of cutting speed and feed per tooth. The analysis of the results considering that this steel has microstructure composed of ferrite and austenite grains with different elastic recovery rates.

Effect of the Cutting Velocity and Heat Treatment on Turning Cutting Forces of an SMA Cu-Al-Be Alloys

This work studies the effect of heat treatment and cutting velocities on machining cutting forces in turning of a Cu-11.8%Al-0.55%Be shape memory alloys. The heat treatment was performed to obtain samples with austenite and martensite microstructures. Cutting force was investigated using a 3-component dynamometer in several revolutions and data were analyzed using statistic tools. It was found that the resultant forces were higher in quenched alloy due to the presence of Shape Memory Effect. Chip formation occurred in a shorter time in the sample without the Shape Memory Effect.

Dynamics of 2-DOF Micro-end-Milling System Considering Grain-Size Variation

Non-smooth systems are employed to model different cutting processes including milling and oil drilling. This article deals with the modeling of the micro-end-milling dynamics with inhomogeneous materials. The model considers a non-smooth system composed of a primary system that represents the tool and a secondary system, representing the workpiece. This system mimics micro-end-milling dynamics considering a progressive motion of the tool holder with tool run-out. The relative position of the tool holder and the chip is evaluated avoiding huge displacements of the tool tip when the tool is not in cutting. The simplified dynamics presented in this article is used as a methodology to calculate the cutting force and tool performance from the prescribed trajectory. The inhomogeneity is related to the description of the micro-machining process where material properties cannot be considered as constant due to grain structure as the tool moves for cutting. Numerical simulations consider a situation where the grain workpiece has austenitic, ferritic or ferritic-austenitic phases. Microscopic analysis is employed to obtain the property variations. The main goal is to establish a qualitative comprehension of the system dynamics comparing results with homogeneous material cutting process.