Chatter stability investigation of micro-milling dental bur at enamel and dentin layers
Ali
Mokhtari
PhD student / Yazd university
author
Abbas
Mazidi
Mechanical Engineering Department, Yazd University
author
Mohammad Mahdi
Jalili
Associate Professor/ Mechanical engineering department, Yazd University, Yazd, Iran
author
text
article
2020
per
Tooth restoration is the most frequent operation in dentistry. During this process, chip can be removed from carious or damaged restoration part of tooth by a high-speed rotating dental bur. The dental bur used in this process is very close to a micro-milling tool. An undesired phenomenon that can occur during micro-milling operations is called regenerative chatter. This is a kind of unstable self-generative vibration. Incidence of this event may leads to limit the efficiency of dentistry through a diminution in the dental bur life-time and physical harm to the tooth or dental bur. The main object of current research is chatter stability investigation of dental bur in enamel and dentin layers. The dental bur is modeled as a nonlinear rotating clamped-free Timoshenko beam that is excited by cutting forces. In addition, the length scale parameters and real geometry of dental bur are considered here. The specific cutting force coefficients for the two main dental layers are obtained by using finite element software. The delay partial differential equations of dental bur are solved in analytical form. Finally, the effects of the tool diameter, the number of the cutter flutes, the tool length, and length scale parameter on the chatter stability in the two main layers have been investigated. To the best author's knowledge, the chatter stability for the dental bur in the two main layers is obtained for the first time in current study by using analytical procedure.
Iranian Journal of Manufacturing Engineering
انجمن مهندسی ساخت و تولید ایران
2476-504X
7
v.
7
no.
2020
1
13
https://www.iranjme.ir/article_114178_774aba3ff186e7292b210d23eb019540.pdf
Experimental Investigation of Aluminum Foam Sandwich Panels under Quasi-static Loading
Saeed
Darab
M.A student/Department of Mechanical Engineering/ Tafresh University/Central Province/ Iran
author
mohammad hossein
pol
Faculty of Mechanical /Department of Mechanical Engineering/Tafresh University/Central Province/Iran
author
Abbas
Rahi
Faculty of Mechanical & Energy Engineering, Shahid Beheshti University, A.C., Tehran, Iran
author
text
article
2020
per
In this paper, the specific absorbed energy (SAE) and mechanical properties of aluminum foam sandwich panels with composite surfaces under quasi-static loading were studied experimentally. The core of the samples are aluminum foam blocks with thicknesses of 1 cm, 2 cm and 3 cm. 2D-woven E-type glass fibers with surface density of 200 Kg/m2 and epoxy resin were used for fabrication of the surfaces. From adhesion of resin was used for bonding to the core and surface. the effect of changing the thickness and density of the core, the composite surface, the surface on one side of the core, the multilayered core having an equivalent thickness, the effect of changing the density of the aluminum foam core is studied and SAE values of the samples were compared. The results showed that increasing thickness of the aluminum foam from 2 cm to 3 cm increased the SAE between 12% and 26%. The use of composite surface reduces the amount of SAE. The multilayer core increased the SAE in the linear elastic zone and at the other force levels decreased the maximum of 6% of the SAE. Moreover, increasing the core density increased the degradation force and reduced the amount of displacement.
Iranian Journal of Manufacturing Engineering
انجمن مهندسی ساخت و تولید ایران
2476-504X
7
v.
7
no.
2020
14
23
https://www.iranjme.ir/article_114179_b3bf2e8955e1283b088dbff2f028f901.pdf
Investigating machining factors of recovery powder metallurgy parts, from filings and sintered by Design of experiments in conjunction with sensitivity analysis
Moiein
Taheri
Assistant Professor, Department of Mechanical Engineering, Arak University, Arak, Iran
author
Seyed Hasan
Bathaee
Department of Mechanical Engineering- Tarbiat modares University, Tehran, Iran
author
text
article
2020
per
Recovery of machined filings in the form of powder used in the metallurgy industry has a very favorable economic advantage. In order to optimize this process and maximize the efficiency of recovering gray cast iron filings by spray mill method, the experimental design techniques are used in conjunction with the sensitivity analysis in this paper. By Design of experiments based on the response procedure, four main factors were extracted as input variables including cast iron powder, compression pressure, sintering temperature and sintering time. These input variables are investigated on three important outputs of machining capabilities including axial force, drilling torque and surface roughness based on sensitivity analysis. The sensitivity analysis method, which is based on the analysis of variance, is E-fast. The sensitivity analysis is a statistical method results in describing the quantitative and qualitative changes of the input variables on the output factors. For the axial force, the effect of the input variables was obtained with 37%,31%,27%,5% for cast iron powder, sintering temperature, compression pressure and sintering time, respectively. Also for drill torque, parameter impressment is 44% cast iron powder, 38% compression pressure, 15% sintering temperature and 3% sintering time, respectively. Cast iron powder percentage, compression pressure, sintering temperature and time have impressed on surface roughness, respectively with 26 %, 49 %, 19%, 6%.
Iranian Journal of Manufacturing Engineering
انجمن مهندسی ساخت و تولید ایران
2476-504X
7
v.
7
no.
2020
24
37
https://www.iranjme.ir/article_114180_54ae3f40b71aaf8e2aeeff0f0b8bf0b7.pdf
Study on the effect of thickness of layers, temperature and speed of nozzle on circularity error and surface roughness of holes in parts produced during fused deposition modeling
payam
saraeian
Department of Mechanical Engineering, Faculty of Mechanics, Islamic Azad University North Tehran Branch, Tehran, Iran
author
ehsan
shakouri
Mechanical Engineering, Faculty of Mechanical Engineering, Islamic Azad University, North Tehran Branch, Iran
author
text
article
2020
per
Due to the increasing need of industries to prototyping with the highest accuracy and lowest cost, the application of rapid prototyping technology as a modern and rapid method has been considered to reduce the time between design to production and market to product. Fused deposition modeling is one of the most common methods in 3D printing and rapid prototyping, but the components produced in this way are usually of poor geometric accuracy and surface quality. Circularity error in the cavities is one of the important geometrical and tolerances errors. In this study, the experimental study the effect of process parameters such as layers thickness, temperature and speed of nozzle on the surface roughness and circularity error of the samples is investigated. The sample is a rectangular that has three holes in three different plates and the measurement of circularity error and surface roughness have been done in three directions and three different plates, respectively.The results showed that the lowest values were obtained for the surface roughness of the holes in the XY plane for a nozzle temperature 270 °C, printing speed 30 mm / s and layer thickness 0.2 mm. Also, the minimum value for the circularity error of the holes was obtained on the XY plate for the nozzle temperature 210 °C, printing speed 30 mm / s and layer thickness 0.4 mm. During the response surface optimization, the model optimized value was 1.174 μm for the surface roughness and 0.114 mm for the circularity error.
Iranian Journal of Manufacturing Engineering
انجمن مهندسی ساخت و تولید ایران
2476-504X
7
v.
7
no.
2020
38
50
https://www.iranjme.ir/article_114181_0e57a92b8f0cae2b1dac71956c244272.pdf
Study and investigation of cutting energy and chip formation in the grinding process of polyether ether ketone
Mohammad
Khoran
Esfarayen University
author
Bahman
Azarhoushang
KSF institute, HFU, Tuttlingen, Germany
author
Hossein
Amirabadi
Neyshabour University
author
text
article
2020
per
Polyether ether ketone has special attention due to its unique mechanical and chemical properties in the aerospace and medical engineering industries. One of the uses of this material is the manufacture of implants in the medical industry and its replacement with metals in the aerospace industry. The grinding process as one of the most important cutting process has high specific energy among the traditional methods. Specific energy is defined as the energy required to cut a unite volume of material. By calculating the cutting energy and comparing with the specific grinding energy (experimental), can determine the contribution of the chip formation energy to the plowing and frictional energy. The Differential scanning calorimetry (DSC) test and theoretical calculations showed that the amount of chip formation energy was 0.12 (J/mm3) while the experimental results showed that the grinding energy was 1.9 (J/mm3). This difference reflects the very high contribution of plowing energy in the grinding of this material. The ratio of heat of chip formation energy that enters the workpiece was calculated as 36%. Therefore, it can be stated that all the energy except 64% of the chip formation energy enters the workpiece.
Iranian Journal of Manufacturing Engineering
انجمن مهندسی ساخت و تولید ایران
2476-504X
7
v.
7
no.
2020
51
58
https://www.iranjme.ir/article_114182_7627413ae5ede7a8b09d2147f0698be3.pdf
Diagnosis and evaluation of factors affecting corrosion damage detection in health monitoring of cantilever beam by electromechanical impedance method
Seyed Reza
Hamzeloo
Mechanical Engineering, Assistant Professor, Shahid Rajaee Teacher Training University, Tehan, Iran
author
Behnam
Akhoundi
Mechanical Engineering Department, Tarbiat Modares University, Tehran, Iran
author
Morteza
Fatehi
Manufacturing Engineering PhD student of Shahid Rajaee University
author
text
article
2020
per
Structural health monitoring based on electromechanical impedance is one of the methods for real-time monitoring and detection of structural damage using the coupling properties of piezoelectric materials. When a structure is exposed to corrosion, an electrochemical process is initiated and defects occur over the surface of the structure. In corrosion-prone structures, although a slight decrease in the mass is produced, it results in a significant decrease in its mechanical strength, integrity and fatigue life span. Therefore, the precise monitoring of structural health is important for detecting corrosion-induced surface defects and predicting the effect of corrosion on the mechanical properties and integrity of a structure. In this paper, the electromechanical impedance method is used to investigate the corrosion defect in the health monitoring of a cantilever beam and to identify and determine the factors affecting the damage index of corrosion. Experiments carried out to measure the impedance spectra on an aluminum beam, and a controlled acid corrosion has been imposed on the beam. The scalar damage index was used to quantify the defect. Empirical results obtained from experiments on cantilever beam show that factors like damage intensity, support positions and damage distance to the support location are effective on damage index caused by corrosion. The results show that there is a relationship between the support location and the damage location with the damage index. Also, it is observed that applied damage index as root-mean-square deviation of impedance has a direct relationship with the intensity of corrosion damage.
Iranian Journal of Manufacturing Engineering
انجمن مهندسی ساخت و تولید ایران
2476-504X
7
v.
7
no.
2020
59
70
https://www.iranjme.ir/article_114184_e93bb27f9fc052260a5cae28266fb7c7.pdf