scholarly journals Experimental Investigation of Deposition Pattern on the Temperature and Distortion of Direct Energy Deposition-Based Additive Manufactured Part

2020 ◽  
Vol 10 (21) ◽  
pp. 7653
Author(s):  
Jaemin Lee ◽  
Hyun Chung
Keyword(s):  
Energy Deposition ◽  
Tool Path ◽  
Coordinate Measuring Machine ◽  
Peak Temperature ◽  
Deposition Pattern ◽  
Direct Energy ◽  
Longitudinal Bending ◽  
Measuring Machine ◽  
Direct Metal Tooling ◽  
Directed Energy

The effect of deposition pattern on the temperature and global distortion of Direct Metal Tooling (DMT) based Additive Manufactured (AM) is investigated through the experimental results of laser deposited SUS316. DMT is one of the Directed Energy Deposition (DED) processes. In situ temperature measurements were used to monitor the temperature of the substrates and global distortion patterns were analyzed using CMM (coordinate Measuring Machine) after the deposition. Six different patterns combining long raster and short raster patterns were considered for the case studies. The results showed that the deposition pattern affects the temperature gradient and that the peak temperature of each layer can increase or decrease according to the sequence of the deposition pattern. Also, the pattern of the first layer had a dominant influence on the longitudinal bending deflection that occurs. Based on these results, appropriate tool path schedule can be utilized to control not only the distortion but also the peak temperature of the DMT-based AM parts.

Ultrasonic Frequency Effects on the Melt Pool Formation, Porosity, and Thermal-Dependent Property of Inconel 718 Fabricated by Ultrasonic Vibration-Assisted Directed Energy Deposition

2020 ◽  
Vol 143 (5) ◽  
Author(s):  
Fuda Ning ◽  
Dayue Jiang ◽  
Zhichao Liu ◽  
Hui Wang ◽  
Weilong Cong
Keyword(s):  
Ultrasonic Vibration ◽  
Inconel 718 ◽  
Energy Deposition ◽  
Pool Size ◽  
Peak Temperature ◽  
Ultrasonic Frequency ◽  
Melt Pool ◽  
Directed Energy ◽  
Pool Formation ◽  
Melt Pool Size

Abstract Ultrasonic vibration-assisted (UV-A) directed energy deposition (DED) has become a promising technology to improve the as-built quality and mechanical performance of metal parts. Ultrasonic frequency, a critical parameter of the ultrasonic vibration, can remarkably affect the ultrasonic vibration behaviors in assisting DED processes. However, leveraging varied ultrasonic frequencies in UV-A DED attracts little attention, and the effects of ultrasonic frequency have been thus overlooked. Linking ultrasonic frequency and part performance emphasizes the need for an understanding of the underlying thermodynamics in the melt pool due to the key role of thermal history in the DED process. In this work, we fabricated Inconel 718 (IN718) parts using the UV-A DED process under different levels of ultrasonic vibration frequency (including 0, 25 kHz, 33 kHz, and 41 kHz). For the first time, melt pool size, temperature distribution, and peak temperature within the melt pool, as well as the peak temperature fluctuation within a layer deposition, were studied. Porosity and thermal-dependent properties including grain size and microhardness were also investigated. The results indicated that the increase in ultrasonic frequency led to an increase in both melt pool size and peak temperature. Moreover, the lowest porosity was obtained at an ultrasonic frequency of 25 kHz, while grain refinement and microhardness enhancement were achieved at the highest frequency of 41 kHz. This investigation provides great insights into the link among ultrasonic frequency, melt pool formation, temperature field, porosity, and thermal-dependent properties in the UV-A DED-built IN718 parts.

Layer Based Robot Machining for Rapid Prototyping

2000 ◽  
Author(s):  
Y. Song ◽  
Y. H. Chen
Keyword(s):  
Rapid Prototyping ◽  
Large Scale ◽  
Tool Path ◽  
Coordinate Measuring Machine ◽  
Cnc Machining ◽  
Stl File ◽  
Machining Center ◽  
Machining System ◽  
Robot Machining ◽  
Measuring Machine

Abstract Many useful methods have been applied to Rapid Prototyping (RP) technologies in recent years, and each of them has its own features. To solve the problem in large-scale prototyping, a robotic machining center with layer based algorithms is developed. Using STereoLithography (STL) file, the surfaces of a model are represented by triangles. Calculating the intersection between a series of parallel planes and the STL file, a STereolithography Contour (SLC) file of the model is generated where the model is represented as a series of contours on a set of parallel planes. Instead of using the popular RP technologies, traditional Computer Numerical Controlled (CNC) machining method is applied in machining each layer of the model. With visibility calculation, the thickness of each material layer is selected. When collision is detected for a point on the tool path, the orientation of the tool is modified. With the machining of a vase model, the effectiveness of the proposed algorithm is demonstrated. Errors of the robot machining system are analyzed by a Coordinate Measuring Machine (CMM) and a surface texture measuring machine.

Fracture Prediction Based on Evaluation of Initial Porosity Induced By Direct Energy Deposition

2021 ◽  
Author(s):  
Roya Darabi ◽  
Erfan Azinpour ◽  
Jose Cesar de Sa ◽  
Margarida Machado ◽  
Ana Rosanete Reis ◽  
...  
Keyword(s):  
High Performance ◽  
Energy Deposition ◽  
Material Model ◽  
Experimental Methodology ◽  
Initial Porosity ◽  
Stainless Steel 316L ◽  
Present Contribution ◽  
Direct Energy ◽  
Directed Energy ◽  
Porosity Analysis

Additive manufacturing (AM) of metals proved to be beneficial in many industrial and non-industrial areas due to its low material waste and fast stacking speed to fabricate high performance products. The present contribution addresses several known challenges including mechanical behaviour and porosity analysis on directed energy deposition (DED) manufactured stainless steel 316L components. The experimental methodology consisting of metal deposition procedure, hardness testing and fractographic observations on manufactured mini-tensile test samples is described. A ductile fracture material model based on the Rousselier damage criterion is utilized within a FE framework for evaluation of material global response and determination of initial porosity value representing the structure’s nucleating void population. Alternatively, the initial pore sizes are characterized using the generalized mixture rule (GMR) analysis and the validity of the approach is examined against the experimental results.

A Method for Measuring the Systematic Errors of CNC-Machine Tools

2012 ◽  
Vol 271-272 ◽  
pp. 1770-1775
Author(s):  
Qi Gao
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Tool Path ◽  
Laser Interferometer ◽  
Coordinate Measuring Machine ◽  
Calibration Method ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Measuring Machine ◽  
Error Calibration

The method used for measurement and calibration of machine tool errors should be general and efficient. With this method, the machine tool status can be completely identified and its accuracy can be enhanced by software error compensation. The point compensation method can be used as a means for modifying the nominal tool path and on-machine inspection where the machine tool is used as a coordinate measuring machine. The validity of the error calibration method proposed in this' paper was shown using a vertical 3-axis CNC machine with a laser interferometer and a ball bar technique.

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