نشریه مهندسی مکانیک مدرس
سال بیست و دوم شماره 10 (مهر 1401)

Proceedings of 2 nd Iranian National Conference on Advanced  Machining and Machine Tools (CAMMT).

Waspaloy is a type of nickel-based superalloy that is mainly used in aircraft turbine parts, compressor disks, shafts, and turbine parts. Waspaloy, like many nickel-base superalloys, is difficult to a machine at room temperature (conventional machining). In this paperwork, the cutting force and temperature created in the cutting area of the workpiece by changing different cutting parameters: cutting speed, feed rate, and constant depth of cut, in the dry oblique turning process of Waspaloy investigated. The hardness of the tested workpiece was 382±3 Vickers. In order to investigate the cutting force and the temperature of the cutting area, a full factorial experiment design without repetition was used, and a regression model of the influencing factors was presented to estimate the cutting force. Specifically, by an increase in the feed rate from 14 to 42 (mm/min), the most cutting force change occurred when the cutting speed was 1200 (rpm) and the depth of cut was 0.3 (mm). Moreover, except in test 6, the machining temperature increased with the rise of cutting speed and feed rate in all experiments.

The use of aluminum with a reinforced coefficient to increase this material compared to aluminum is used in the automotive, aircraft, and locomotive industries. This article examines the parameters of the material removal rate (MRR) rate and surface quality in the machining process of composite aluminum in different percentages of SIC. It examines the machining characteristics of end milling operations to obtain minimum surface quality, cutting force, and chip removal rate with maximum material removal rate using gray relational analysis based on the response surface design method (RSM). Twenty-seven experimental runs were carried out based on the response surface design method (RSM) by changing the parameters of spindle speed, feed, and depth of cut in different weight percentages of reinforcements such as silicon carbide (SiC-5%, 10%, 15%). And alumina (5-5% Al2O3) in the aluminum metal base 7075. Gray relation analysis was used to solve the multi-response optimization problem by changing the weights for different responses based on quality or productivity process requirements. The results show that spindle speed and SiC weight percentage are the most important factors that affect the machining properties of hybrid composites.

Thread whirling has been used in manufacturing spine screws instead of normal threading. The main advantage of thread whirling is high-speed production along with high precision. In this method, a whirling module and tool holder with specialized inserts have been used. The mentioned module is adjusted and connected to the machine at different angles according to the geometry of the thread. In this research, the thread whirling method was conducted on four pedicle screws made of Ti6Al4V to investigate the effect of the main cutting parameters, including cutting speed and feed rate on the surface integrity and dimensional accuracy. Based on the results, the obtained tolerances of the threads were in the acceptable range. In addition, the increased cutting speed reduced the surface integrity of the threads by plowing.

Nowadays, Inconel superalloys are often used in various industries due to their extraordinary properties. Some unique properties of Inconel, such as maintaining its yield strength at elevated temperatures, very low thermal conductivity, and high abrasion resistance, provide very difficult to cut conditions for machining this superalloy. This paper presents a method for simulating the direct aged Inconel 718 superalloy turning by using the power law equation based on the finite element method. One of the main objectives of this research is the correct determination of material properties based on power law equation such as strain hardening coefficients, strain rate sensitivity coefficient, thermal softening coefficients, and other coefficients required to simulate direct aged Inconel 718. The simulation results, such as shear plane angle, machining forces, chip temperature, and tool and chip shape, have been validated by reference [1]. This study, similar to [1], has been studied at three different undeformed chip thicknesses to examine the deformed chip thicknesses and other machining outputs such as machining forces using the power law equation. Third wave Systems-AdvantEdge software has been used for the current study. The output of this study has been investigated with the results of experimental research [1] and shows the high efficiency and accuracy of the present analysis.

Mounted point grinding is a machining method to reduce surface roughness and improve surface finishing on workpiece walls and hard-to-reach areas. This process is usually used without preparing the grinding wheel before and during the grinding operation, which reduces the proper performance of the process. Environmental contamination, surface integrity, coolant-lubricant-related diseases that affect workers' health, and machining costs heavily depend on the appropriate dressing and proper coolant-lubricant usage. In this study, as a novel approach, the effects of dressing conditions (depth of dressing and dressing feed rate) and the feed rate of the workpiece during the grinding of a hardened Mo40 steel workpiece in two traditional cooling-lubricant minimum lubrication environments have been investigated. Surface roughness and wheel loading are two significant outputs in every grinding operation. The experimental result of this study reveals an improvement in enhancing the surface roughness in a soft dressing. Moreover, another aim of this study was to achieve proper surface roughness by implementing minimum quantity lubrication to significantly reduce total cutting fluid usage compared to traditional continuous coolant-lubricant. In this study, higher wheel loading in the Minimum Quantity Lubrication (M.Q.L.) technique was observed compared to the traditional continuous coolant-lubricant technique.

Boring is a process which the diameter of the internal hole of the workpiece usually increases from the initial size to the desired value in some stages. In this operation, undesired vibrations lead to decrease in the smoothness of the surface; thus, active dynamic absorbers have been used to dampen the vibrations. In this research, two analog and digital accelerometers are used with an active dynamic absorber installed on a 720 mm boring bar. The analog sensor is used as a validation of the economical digital accelerometer. Therefore, thanks to the velocity feedback method, the vibrations caused by any impact forces have been damped and compared with the state without the presence of an active dynamic absorber. Furthermore, in this research, by increasing the amount of input voltage to the amplifier, the damped results of the impact applied to the end of the cutting tool have been increased remarkably and the frequency spectrums have been presented and examined to predict the damping.

Metal and especially aluminum mirrors have wide applications in the optical industry due to their desirable properties, hence requiring very high polished surfaces. One of the methods of preparing aluminum mirrors is single-point diamond turning. In this research, the manufacturing process of 6061-grade aluminum mirrors has been studied using diamond turning and consequent polishing process in order to reach surfaces with acceptable optical properties. In the first part, the effective range of turning parameters was determined. The results showed that the feed values less than 5 μm/rev, the cutting-edge radius between 0.2 and 0.8 mm, and the rotational speed of 2250 rpm have a greater effect on the surface roughness. In the second part of the research, initially, the turning process was performed with effective parameters and then the polishing process was applied as the final finishing process. Surface finish is evaluated by surface roughness and surface interferometry parameters. The results showed that the smaller surface roughness after the diamond tool turning process led to higher optical properties after the final polishing process. The lowest PV value equal to 0.293 μm was obtained by diamond turning with 3 μm/rev and a cutting-edge radius of 0.8 mm.

In orthopedic surgery, the drilling process is used to internally fix the fracture zone. During bone drilling, if the temperature exceeds the limit of 47 °C, it results in altered bone alkaline phosphatase nature, occurrence of thermal necrosis, non-fixation and inadequate bone fusion In order to investigate the effective parameters of the drilling process, after three-dimensional modeling of the femur bone in Mimics software and determination of bone coefficients based on the Johnson-Cook model, numerical simulation of the cortical and trabecular bone oblique drilling process have been performed. The drilling process was performed in both normal and high speed modes based on reverse heat transfer theory using DEFORM-3D software. The results of numerical simulation after validation with experimental results showed that this theory is capable of estimating the temperature and heat flux in this process and the occurrence of necrosis in both processes (normal and high speed) is imminent. The temperature in the drilling area of the trabecular bone is higher than the cortical bone at all speeds and feed rates and the axial force of the trabecular bone is less than the cortical bone at all speeds and feed rates. The optimum point leading to the minimum temperature in normal drilling of trabecular and cortical bone is the feed rate of 150 mm/min and the rotational speed of 2000 rpm. This optimum point is obtained in the high-speed drilling of trabecular and cortical bone at the feed rate of 150 mm/min and rotational speed of 4,000 rpm and 7,000 rpm.

The non-reproducibility of the measured results of a piece by reference laboratories is a problem that often causes differences of opinion in production workshops and doubts about the adjustment of production devices with the results provided by laboratories. In this paper, the effect of geometric parameters created by machining on the ability to measure control tools through statistical techniques of quality engineering is investigated, so that first a piece was subjected to drilling and machining, after measurements The exact diameter of the hole with geometric deviation was determined to be cylindrical error to 0.01 mm. Then it was examined with two common measuring systems of air gauge and coordinate measuring machine (CMM) and the capability of the instruments was calculated as follows through the mini-tab software. Capability of air gauge (Cg) in measuring the diameter of hole was 0.27 and capability of CMM device in controlling the said diameter was 0.28. After removing the scattering caused by geometric parameters to calculate the ability of measuring instruments, The power of the instruments was improved to 1.20 in the wind gauge and 1.05 in the CMM and finally, by removing or reducing the geometrical error of the work piece, the repeatability (VARIATION) and the ability of both measurement systems are improved to many times.

The use of aluminum with a reinforced coefficient to increase this material compared to aluminum is used in automotive, aircraft and locomotive industries, in this article, while examining the cutting force and erosion of tools on the machining process of composite aluminum in different percentages of SIC, the machining characteristics are investigated. The end milling operation is performed to obtain the minimum cutting force, tool wear with the maximum removal rate using gray relational analysis based on response surface design method (RSM). Twenty-seven experimental runs were carried out based on the response surface design method (RSM) by changing the parameters of spindle speed, feed and depth of cut in different weight percentages of reinforcements such as silicon carbide (SiC-5%, 10%, 15%). and alumina (5-5% Al2O3) in the aluminum metal base 7075. Gray relation analysis was used to solve the multi-response optimization problem by changing the weights for different responses based on quality or productivity process requirements. Proper selection of input parameters (spindle speed 1000 rpm, feed 0.03 mm/rev, depth of cut 1 mm and 5% SiC) produces high material removal rate with fine surface, less tool wear and low cutting force.

Given the current demand for surfaces with non-polished morphology like structured surface that enhance its tribological properties, providing a method with minimal production cost and high performance has attracted attention. The present study focuses on presenting a new method for producing structured surfaces with hydrophobic performance. In this method, using the grinding process with a special grinding wheel, an attempt has been made to produce these widely used surfaces. By modifying the topography of the wheel surface and changing the arrangement of abrasive particles from random to arranged distribution with the diamond particles in predefined locations, an attempt was made to design and manufacture a special grinding wheel for the production of structured surfaces. A segment with 1*1 cm2 including diamond particles with mesh size of 40/50 were manufactured during the electroplating process in a nickel bath medium and by installing the segment on the wheel hub and performing the grinding process with this developed wheel, surfaces containing continuous and discontinuous scratches with the same geometry were produced. Static contact angle test for the unstructured surface was about 37 degrees that improved to 141 degrees with the structured surface, which is an impressive improvement.

In this article, the improved Oxley model, which is actually a combination of the Oxley and Johnson-Cook models, was introduced. The Oxley model does not take into account the effects of strain rate, hardness and heat increase, so by linking the Johnson-Cook model with this model, the Oxley model was developed. In this article, a program was written with Matlab software, which performed the analytical solution of the drilling process with the improved Oxley model, and according to the classical torque formula, the amount of this parameter was calculated according to the tangential force output from the Matlab code. Then the value of torque was compared with the value of this parameter in numerical modeling using AdvantEdge software, The difference between the numerical and analytical solutions is 12.5%, which indicates that the approximation in the presented analytical model is acceptable.

In the polishing process, one of the factors affecting material removal is the contact force between the tool and the workpiece. The contact force parameter is important in the sense that in this process, the amount of this force is lower than other machining processes, as a result, the force contact is one of the important issues to be controlled. In this research, a force control system based on the implementation of proportional-integral-derivative (PID) control algorithm with regulatory strategy in Arduino board is presented. It is possible to apply command signals to the actuator by the Pulse Width Modulation (PWM) unit of the Arduino board. The polishing setup in this research includes solenoid, dynamometer, direct current (DC) motor and belt sander. PID control coefficients were estimated by system identification method and using MATLAB software tools. The results show that the control system designed on the Arduino board provides the desired stability to control the polishing force with an acceptable error. Among other advantages of the developed system, the need for additional equipment is reduced compared to other commercial systems and it is more economical.

Today, the application of materials such as glass has been widely developed in the manufacture of micronutrients, electronics and medical equipment because of its high hardness, chemical resistance and high abrasion. But due to high hardness and low toughness, mechanical machining cannot be applied. The Electrochemical discharge method is a new machining method that is capable of machining hard and non-conductive electrical materials such as glass. In the process of electrochemical discharge drilling, the dimensional accuracy of the hole and especially its inlet area is important. But almost, the inlet of the hole has a high slope, which leads to excessive hole overcut and tapering of the hole side wall. In this study, to remove the high slope entrance area, a thin intermediate part was used which will be separated from the main workpiece after the drilling process. The results showed that mentioned method reduced the entrance overcut of the hole by 50 to 76% depending on the diameter of the tool. Also, the hardness measuring of points on the hole inlet showed that using the intermediate part led to the smaller heat-affected zone (HAZ) around the hole entrance.

In the polishing process, one of the factors affecting material removal is the contact force between the tool and the workpiece. The contact force parameter is important in the sense that in this process, the amount of this force is lower than other machining processes, as a result, the force contact is one of the important issues to be controlled. In this research, a force control system based on the implementation of proportional-integral-derivative (PID) control algorithm with regulatory strategy in Arduino board is presented. It is possible to apply command signals to the actuator by the Pulse Width Modulation (PWM) unit of the Arduino board. The polishing setup in this research includes solenoid, dynamometer, direct current (DC) motor and belt sander. PID control coefficients were estimated by system identification method and using MATLAB software tools. The results show that the control system designed on the Arduino board provides the desired stability to control the polishing force with an acceptable error. Among other advantages of the developed system, the need for additional equipment is reduced compared to other commercial systems and it is more economical.

Electrochemical discharge machining (ECDM) is a novel non-conventional micro-machining method that can be applied to machining hard, brittle and non-conductive materials such as glass and ceramic. Due to the hardness and brittleness of mentioned materials, the application of conventional machining is associated with serious technical problems. In this article, the machining process was performed in two steps, and hole depth is considered as the main machining output. The obtained results of the new method are compared to single pass micro-drilling (a common micro-drilling process). The achieved results indicated that depth improvements of 36% and 70% were obtained for voltages of 33 and 38V. Also, by increasing the diameter difference, a deeper hole can be achieved.

In this article, the effect of optimal selection of vibration and cutting parameters on cutting forces in the machining process with ultrasonic vibration assistance has been investigated and the results have been compared in two modes of conventional machining and of ultrasonic vibration assisted machining. In the investigation of the effect of ultrasonic vibration assistance on the machining process, analyzes have been carried out in different cutting speeds, and the effect of changing the cutting speed in relation to the tool's oscillation speed has been investigated. Finite element modeling and simulation has been done with DEFORM finite element software. The results show that the application of ultrasonic vibration in the machining process leads to the reduction of tangential and axial cutting and the reduction of heat resulting from the cutting process. By examining the results, it was found that in the machining process with ultrasonic vibration assistance, when the cutting speed is at least 30% lower than the vibration speed of the tool tip, the process has a favorable efficiency, and the favorable effects of applying ultrasonic vibration on the process include reducing shear forces, reducing the heat generated From cutting, reducing the friction coefficient between the tool and the workpiece, helping to improve the chip flow, etc.

Ultrasonic machining is a new technique, and one of the new and promising processes for machining metals, especially metal alloys with low machinability. In this paper, a set of laboratory studies is used to investigate the effect of using ultrasonic vibrations on the force required for drilling of the thin aluminum workpieces. For this perpuse, three aluminum workpieces with different thicknesses are drilled under three different rotation speeds, and four different advance rates. The results showed that in two aluminum workpieces, 1 and 1.5 mm, the use of ultrasonic vibrations generally reduced the axial force, but in the 2 mm workpiece, it is not possible to understand a meaningfull effect of adding ultrasonic vibrations. In other words, it can be said that adding ultrasonic vibrations with constant amplitude and frequency does not have the same effect on drilling in different conditions, and to reach the most efficient drilling, the characteristics of optimal vibration should be studied.

Ionic polymer-metal composites (IPMC) are such as smart materials which under applied voltage will be deformed and they have a broad application prospect. On the other hand, increase of surface area of this composite is directly related to bonding between electrode and polymer, as a result, polymer surface morphology is highly important, therefore, the effect of micro-blasting on the dynamic response of the composite beam is investigated. In this research, a membrane from ionic–polymer-metal composites are manufactured. Its main core is based on an electroactive core named Nafion and the electrodes are made of metals such as Platinum which is a noble metal. Then a transient voltage applied to the ionic–polymer-metal composite which was 1 volt and the displacements are measured experimentally. Finally, by the effect of micro-blasting as a surface treatment technique on the composite and comparing experimental results, a suitable equation is proposed for the behavior of this actuator under transient voltage.

electrical discharge coating (EDC) is the simplest way to deposit a thin or thick coating on the surface of a substrate to change the properties of this undesirable layer. In the EDC process, the molten pool produced due to sparking in electrical discharge is combined with material particles from the loosely bonded compacted electrode (green compacted) and then rapidly cooled to form a coated layer. Extensive methods for coating the surface of the substrate exist such as electroplating, electroless plating, vapor deposition methods, thermal spraying and many others. These processes have disadvantages such as high capital costs, complexity, higher setup complexity and space requirements that limit their implementation to some extent. Among all coating methods, EDC has advantages over other coating methods. For EDC, there is no need to set up any equipment to create a vacuum or isolation environment around the bed. Also, only by changing the different variables of the machine, the thickness can be changed and the characteristics of the coating layer can be controlled. This study focuses on chrome ceramic coatings formed in the EDC process on stainless steel substrates (ST37) with process parameters with 8 amp current and 100 μs on time. The results showed that the hardness of stainless steel coated with chromium and copper increased to 1284 (HV) in electrical discharge.

abrasive water jet is one of the most popular cutting methods today due to its ability and unique features such as the ability to cut complex shapes as well as the wide range of materials and non - creation of thermal distortion at the cutting site. The accuracy of the process is mainly due to selecting the cutting parameters. The sheet used in this study is aluminum 7075 with a thickness of 25 mm. In this research, for water jet pressure, forward speed and nozzle distance to the surface of the workpiece, three surfaces and for the impingement angle of two surfaces were considered. In order to investigate the quality of the cut - off area, the effect of process parameters on the high and low width of the cut section and also the cut - surface slope is investigated. Finally, the cut gap created by this process has special geometrical features that in some cases is the limitation of the process. The results showed that the change in the direction of the water jet from the perpendicular to the surface of the work piece, although the width of the cutting crack cannot be changed, the surface quality decreases and the cutting surface slope increases.

Parallel robots, which have several advantages over serial robots, have been one of the important industrial developments to increase the efficiency of controllable devices. Parallel structures have more suitable features such as higher rigidity, higher movement speed, non-cumulative errors and flexibility of the end-effecter pose. However, the workspace of parallel robots, compared to serial robots, faces limitations due to the existence of multiple kinematic chains, as well as the complexities related to robot control. Small size of workspace is one of the main challenges of parallel robots. Designing moving platform of a parallel robot is of the factors affecting the workspace of the robot. C4 is a four-dof parallel robot that is developed based on the three-dof Delta robot. In current study, the influence of the moving platform design on the workspace and efficiency of the robot has been investigated. After the initial overall design of the robot, three proposed modes for the moving platform have been investigated by considering the robot's kinematic parameters and robot error analysis. According to the results of the workspace and the robot efficiency analyses, the most efficient design has been selected.

The chewing simulator is designed to perform fatigue tests and durability on a variety of dental specimens. This device, by considering the material (hard or soft) and the type of dental sample (human or animal or artificial) and by applying a specific cyclic and even static force, changes the shape of the sample microscopically and finally this periodic loading and shape change, uses the data to evaluate the fatigue and strength of the sample in the durability test. The testing process of this device will continue until the sample fails or the loading cycle is completed. At design of this device, two movement mechanisms are considered vertically and horizontally, which are responsible for chewing simulation operations, so that in both mechanisms, the movement is reciprocating, the amount and number of this movement is cyclical that is adjustable and controllable, and at the same time, considering the force measuring sensor in this device, the amount of applied force is specified and adjustable at each stage. Two specimens of teeth were placed in the machine for testing. The first priority of testing this device for the samples was their durability under the static force that was applied to the sample step by step. Also, to evaluate the function of the device in the fatigue test, dental specimens were loaded under a certain force and were affected by cyclic motion in both vertical and horizontal directions. According to studies, the refractive force of the specimens varies from 100 N to 800 N, the dental specimens, one artificial and the other natural, failed under the static force, which was in the range of 200 N, that the artificial sample was completely broken, but the natural sample was worn out and part of it was damaged. And this was a good comparison to show the strength and durability of natural teeth compared to artificial ones.

The milling machines based parallel mechanisms with more than 3-dof. have high stiffnes and flexability in machining of the complicated workpieces. Accuracy and repeatability of these machines will be enhanced by applying calibration procedures. In this paper a 4-Dof milling machine based parallel mechanism was introduced. The required tests to find positioning errors have been done. After applying error compensation process on controller, the positioning errors of each of the rails were measured again. It was resulted the positioning errors of rails have been decreased and the accuracy of milling machine was enhanced.

Choosing the right equipment in terms of price, performance and reliability, is one of the main challenges in the automation industry. Among these equipments, electric motors are the most important elements which are widely used in the industries. Electro motors selection is made according to certain rules and principles, and it is very important to know the governing conditions. Using amotor with less power than required will lead to system failure and a motor with much more power will result in extra costs. In this article, scientific selection of an electric motor for the bending process in an automation system has been discussed. Using real conditions of a manufacturer and available data in articles and books, the necessary relationships were extracted .28 number of motors (among the available ones) were nominated in the first stage of preliminary monitoring. Then, by applying other prevailing conditions and characteristics, 3 motors with different powers selected for final investigations. Eventually, after using Simscape simulations & exerting less energy consumption criteria, the 5RK90GE-CW2ML2 motor (manufactured by Oriental Motor Company) was selected and was approved after satisfying the power, quality and safety conditions.

Computer-aided process planning is one of the challenges for researchers to achieve computer-integrated manufacturing, and setup planning is the core of the CAPP system. Based on the literature survey, it has been observed that researchers use different methods for setup planning, and there is a lack of mathematical models in their methods. However, the mathematical model is necessary to implement and develop the setup planning method. Therefore, in this paper, the permutation-based setup planning was selected to determine the setups, and then the setup planning rules were cast into the mathematical model. Finally, the mathematical model is implemented and evaluated in MATLAB software to ensure the accuracy of this model.

Extracting the required information from the design file is one of the main steps in the computer aided process planning. In previous methods of extracting machining features, various methods such as graph-based method, volume analysis method, logic rules method and other methods have been used. In all the previous methods, whether traditional methods or methods based on artificial intelligence, the input data to the machine feature identification system is the output information of a computer-aided design system. Converting the output information of a computer-aided design system to input data of a machining feature identification system is faced with limitations such as the variety of format and type of data arrangement, deleting some data from the design file due to geometric interference of features, slow extraction of features due to extensive information in the design file and the limitation of identifying different types of machining features by a unity feature identification system. In the present study, using artificial intelligence techniques based on deep learning, machining features are extracted directly from the two-dimensional image of a workpiece. The image may be prepared by a computer-aided design file, or it can be taken by a camera.

Micro-milling process as one of the most widely used methods of making parts due to the small size and their delicate properties in the process. In this study, micro-milling operations were performed on a titanium piece made of Ti6Al4V alloy using a tool with a diameter of 0.5 mm. The effect of nanoparticles used in lubricants on the surface roughness of the micro-milled workpiece is the most important characteristic studied in this research. In this research, experimental test methods and design and analysis of experiments by Taguchi method have been used to study the surface roughness during the process. Experimental tests to compare the role of lubrication in dry, wet and Minimum Quantity Lubrication (MQL) in different machining environments with lubricants containing nanoparticles and without nanoparticles and the effect of shear parameters on different characteristics of micro-milling of Ti6Al4V alloy is done. The results show that the use of Minimum Quantity Lubrication (MQL), especially with lubricants containing nanoparticles, increased the surface quality and had a more effective role in lubrication during micro-milling of Ti6Al4V alloy. Spindle speed

In ultrasonic vibration-assisted turning, an ultrasonic vibration is added to the tool, which leads to the periodical disengagement of the tool and the work-piece. In this research, an experimental study of ultrasonic vibration-assisted turning and conventional turning on Ti6Al4V Titanium alloy is conducted. First, by analyzing different parameters, four parameters are selected as the main affecting input parameters (cutting speed, feed rate, depth of cut, and ultrasonic vibration), and the effects of these four parameters are studied on two output parameters, namely tool wear and surface roughness. After the experimental tests, a statistical analysis is performed on the results and a neural network model is developed to predict the tool wear and surface roughness. The results show that the developed neural network model has a good agreement with the experimental results. In all experiments using ultrasonic vibrations, the tool wear and surface roughness were lower in comparison with the conventional turning. The cause of the tool wear and surface roughness reduction in ultrasonic mode are reducing the average forces applied to the tool, the alternative disengagement between the tool and the workpiece and increased dynamic stability of the process.

The high costs and problems in finishing machining, especially aluminum alloys, have increased the importance of surface treatment processes without chipping, such as burnishing. In this paper, in the burnishing process of AA7075-T6 aluminum plate, the effect of vertical depth and lateral pass on the surface roughness was experimentally studied with a new approach of choosing the lateral pass as a variable depending on penetration radius of the burnishing. The results of interaction effects of the input parameters showed that, in general, the quality of the surface increases with the reduction of the lateral pass and vertical depth. At lower values of vertical depth, with the increase of lateral pass, the increase of surface roughness occurs with a slower slope which shows that in the lower vertical depths, a larger lateral pass can be used to achieve the desired surface quality in a shorter process time. The highest percentage of surface roughness improvement was about 96%. Simultaneous examination of the results of roughness and process time showed that burnishing with vertical depth and lateral pass of 0.04 and 0.33 mm, respectively, which improves the surface roughness by 86.63% in an effective time of 1.86 minutes, had the best performance index.

Magnetic abrasive finishing process (MAF) is one of the latest advanced machining processes. After eight decades have passed since the registration of the magnetic abrasive polishing process, the applicability of this method has been proven in finishing all kinds of surfaces, including flat, cylindrical and free surfaces. In this research, the influence of MAF process movement parameters on the concave surface of cold-worked steel has been investigated experimentally using the response surface method. These parameters include rotational speed, linear speed, gap between abrasive brush and workpiece, magnetic flux density and curvature angle. For this purpose, a spherical head magnet is used and the powder used is prepared by mechanical alloying method. Cold-worked steel is used in the manufacture of roll forming molds, which is used in air engines to shape compressor and turbine blades, and also to investigate the feasibility of the MAF process on the workpiece surface with high hardness and yield stress, such as Cold work steel is selected. According to the results, the optimal value of the magnetic flux density is 0.55 tesla, and with the increase of the distance between the abrasive brush and the workpiece, the surface roughness changes initially increase and decrease after passing the optimal value.

Wear, friction and lubricant are important issues in all disciplines, including in turning. Normally, lubricant is used to reduce the temperature of the tool and also to reduce the friction between the part and the tool. So far, many studies have been done on lubricant optimization by changing its structure, for example by adding nanoparticles to the lubricant. In this article, with a new approach, the effect of creating a surface pattern on the accuracy of the lathe has been studied. More precisely, the effect of holes created by laser engraving on the friction behavior and the formation of the fluid layer in different states were investigated by numerical analysis. In general, the amount of load as well as the speed of chipping is an influencing parameter on the amount of friction. Here, by keeping these two parameters constant, the effect of the number, depth and size of the surface pattern was investigated.

In this study, the effect of selective laser melting parameters on the mechanical properties of iron has been experimentally investigated. The mechanical properties discussed in this article are ultimate tensile strength. The selected parameters include the laser power, the laser scanning speed, and the laser hatch distance, and the design of experiments was done by the Taguchi method. By examining the microstructure, the optimal range of the mentioned process parameters was determined to achieve the highest tensile strength. The results show that the optimum parameter levels for the tensile strength include the laser power of 200 watts, the laser scanning speed of 600 millimeters per minute, and the hatch distance of 70 micrometers.

With the development of additive manufacturing technology, the quantity of devices that can be used in small office with the commercial or educational purposes increases. In this research, the goal is to build a desktop 3D printer with selective laser sintering technology, which can be used for research purposes. The main concentration is focused on fabrication with parts that can be manufactured in the country or can be procured from the domestic market. It is also tried to make the 3D printer compatible with the common open-source additive manufacturing softwares. The fabricated 3D printer has the ability to work with all kinds of common polymer powders. In addition, it is easy to update the device's firmware according to the researcher's needs. The capabilities of the device was tested with Glucose powder, paraffin wax powder, and thermoplastic-ceramic material combinations. It is currently used for research on fabricating ceramic parts with indirect laser sintering.

In recent years, topology optimization has been used as an innovative approach to design lightweight and high-performance components. Despite the high variety of developed topology optimization approaches, only a limited number of them can be used in commercially available software programs, and in particular, for complex geometries. Three different types of these methods have been utilized and investigated in this research. In the first step, an industrial part is redesigned for topology optimization. Then, the volume of this part is reduced by 60% by three different methods of Continuous Compliance Optimization (CCO) , Discrete Compliance Optimization (DCO) , and Stress-Constrained Optimization (SCO) . Then, a number of parameters, such as the maximum stress and displacement, safety factor, error of convergence, the final weight, and the computational cost of each approach are assessed. Finally, in a nutshell, it can be concluded that despite the differences in the performance and result of each method, all of them are applicable, but the SCO method could achieve the best result due to the minimum stress concentration and final weight. It is noteworthy that topology optimization configurations have many complexities and can only be produced by additive manufacturing technologies due to their potential and flexibility.

Today, additive manufacturing methods have found wide applications in various industries due to their many advantages, including not needing tools and molds, as well as short production time. Among these methods, the FDM process is widely used due to its cheapness and ease of production. As a result, it is very important to discover the relationship between the mechanical properties of the product produced in this way and the parameters used in the process. In this research, the effects of layer lamination angle, infill extrusion width and layer thickness on the normal force and tensile strength of PLA printed samples are examined. In order to investigate the effects of the parameters, the design of experiment, using surface response and Box-Benken method was used with the help of Minitab software. The results of the tests show that the maximum tensile strength and normal tensile force of the printed samples were equal to 38.36 MPa and 1.50 kN, respectively, which is at zero-degree lamination angle, infill extrusion width of 150% and the thickness of the layer 0.3 mm.

Nowadays using 3D printing for prototyping is well known in industrial applications and there are efforts to make functional parts with this technology to reach low volume production markets. By using pellets rather than filaments, the limitations caused by lack of variety of materials can be conquered. Also there will be no need to make a massive part as several divided parts and then glue them together. In this article pellets of ABS, that are well known and functional in industry, are analysed for an extruder to investigate the ability of pellet material extruding. Characteristic specifications of extruder such as operating pressure, screw rotational speed and required torque for rotating the screw are achieved for they are important factors to find out the mechanism for experimental tests and selecting suitable operating parts such as motor and gearbox.

Nowadays, one of the most important problems in industry is the production of industrial parts from superalloys and metals with high hardness using traditional and modern machining methods, due to the waste of raw materials, wear of machining tools, and the inability to produce complex geometries. Selective Laser Melting is one of the sub-branch of additive manufacturing technology that provides the fabrication of complex geometries from widely-used metallic materials due to the layer-by-layer production of parts. Hastelloy X superalloy is among the important superalloys in the aerospace industry and gas turbines. This research aims to fabricate Hastelloy X parts by selective laser melting with minimal defects and high relative density. For this purpose, three samples were printed in the range of volumetric energy density of laser from 50 to 90 J/mm3. The structure and porosity of different specimens were evaluated by image analysis method. It was found that the sample fabricated with the volumetric energy density of 90 J/mm3 has the least defects, the highest hardness, and a relative density above 99 percent.

Fused deposition modeling (FDM) is one of the most common 3D printings technologies. Low cost and the ability to produce models using wide range of thermoplastic makes this process suitable for rapid prototyping and manufacturing some commercial parts. The mechanism of this printer is 4-DOF parallel machanism with one additional degree of freedom resulting from rotation of printer bed about z-axis. In order to generate tool path for 5-DOF printer, a CAM software was developed with python. For controling the printer, control software was designed based on open-source marlin framework. Since original framework only supports 3-axis printers, source code needed to be changed such as extending source code to support 5-axis and adding machanism inverse kinematics. By using this 5-Dof mechanism, the prints of complicated parts without using the support are possible.

Using optical absorbers is one approach to manage and decrease the intensity of any light source. The digital light processing (DLP) additive manufacturing system created and implemented by the authors of this article was utilized in this study to examine the impact of ultraviolet light absorber on the quality of manufacturing 3D items. The article's major objectives are to enhance part appearance quality, maximize printing control, and reduce excess light, but in order to do so, it is crucial to measure the height of separation, the degree of part damage and the Separation Force. Undoubtedly, one of the factors having the most impact on the aforementioned scenarios will be the optical absorber. Therefore, in this system, acrylic sheets are coated with polyester films that have an absorption percentage of 45% at specific distances from the light source. Then, using the DLP method, three-dimensional models were created and assessed by measuring the intensity of the transmitted light. According to the study's findings, using absorbers decreased the time it took to separate each layer by 3.5 times, cut the time it took to print a part by 43%, and increased the success of printing, while also increasing the product's aesthetic quality.