The most essential problem in lapping process is low material removal rate which leads to increase in production costs and time. Thus, in this process, it's essential to select a condition that besides producing pieces with required flatness and roughness, has a high material removal rate. In this research, effects of parameters such as abrasive particle size, abrasive particles concentration in slurry, and lapping pressure on material removal rate, flatness and surface roughness were studied by experimental method in single sided lapping of flat workpieces made of 440c steel. In the following, effect of aforementioned parameters on material removal rate, flatness and surface roughness of lapped surface has been modeled using artificial neural network. Finally, by exerting multi-objective particle swarm optimization, simultaneous optimization of material removal rate, surface roughness and flatness of lapping pieces has been conducted and related Pareto front has been obtained. Obtained results show that by using Multi-objective particle swarm optimization algorithm we can produce workpieces with required surface roughness and flatness with high material removal rate. Consequently, by using this method moreover producing workpieces with desired quality, production cost and time would decrease.

Electrical discharge machining (EDM) is a modern machining method which in pace with industrial developments, various studies are aimed at improving this process's parameters including material removal rate. In previous researches, changes in machining tool’s properties and specifications have been investigated as the solution to improve the material removal rate. A novel and efficient process to change material microstructure and properties is equal channel angular pressing (ECAP) that is appropriate method to produce fine grains materials with high strength and adequate properties. In this study, the pure copper material was processed through 4 and 8 passes of ECAP and its effect as a toolfor EDM process, on material removal rate, with different discharge current and pulse ontime was examined. Microstructure of the specimens were analyzed after ECAP operation using electron back scatter diffraction method (EBSD), and the average diameter of grains for specimens were measured using this technique. The results of the experiments indicated that processing the copper tool with ECAP through 4 passes, increases the material removal rate up to 13.2 percent. Moreover, increasing the number of passes of ECAP from 4 to 8 improved the effectiveness of this process on increasing the material removal rate up to 5.5 percent.

Abrasive flow machining (AFM) is a relatively new process with low material removal ratio for deburring, removing recast layers and finishing industrial components with complex shapes among non-conventional machining processes. In this process, the finishing is handled by flowing of the composition of viscoelastic and abrasive particles on workpiece surface, under the pressure of piston. In this research, the abrasive flow machining process of H13 tool steel with applied an external magnetic field around the workpiece for improve the material removal ratio and surface roughness has been investigated and the effect of magnetic field intensity, abrasive particles mesh and the hardness of workpiece as the input parameters on the process outputs including surface roughness and material removal ratio was studied. Also the regression model of MRR and surface roughness was developed and variance analysis was performed. Results of experiments indicated that increase in abrasive-particles mesh leads to decrease surface roughness and material remove ratio and increase in magnetic field intensity causes to increase material removal ratio and decrease surface roughness. Also the material removal ratio is decreased with increasing of workpiece hardness and on the same condition; better surface finish was achieved in the case of harder workpiece.

In this study the effect of input parameters of the EDM process including pulse on- time، pulse current and voltage on the output characteristics (material removal rate، tool wear ratio and surface roughness) in the machining AISI D6 tool steel has been studied. This study shows that increasing the pulse on time، material removal rate and the surface roughness are increased and the tool wear ratio is reduced. Also، based on obtained results by increasing pulse current، material removal rate، tool wear ratio and surface roughness are increased.

In this research the abrasive flow finishing process (AFF) of AISI H13 hot work steel was studied and the effects of various process parameters such as flow pressure (extrusion pressure), abrasive particles densities, abrasive particles sizes and the first quality of surfaces on variations of surface roughness and material removal have been investigated. The results showed that increasing the density of abrasive particles leads to increase in variations of surface roughness and material removal. Increase of extrusion pressure from 4 to 6 MPa causes the increase in variations of surface roughness and material removal and from 6 to 8 Mpa leads to decrease in the two latter. Electron microscopic results showed that increase of finishing process time over 4 hours causes a detrimental effect on the surface of the specimens, as a result of penetration and stabilization of abrasive particles in the form of broken particles. Also according the results of this paper, increasing the size of abrasive particles leads to higher variations of surface roughness and material removal, and this process is more effective in finishing of rougher surfaces.

Abrasive Flow Rotary Machining (AFRM) is a new form of Abrasive Flow Machining process (AFM) which has been recently introduced by the authors as one of the non-conventional finishing and polishing methods. Since in AFM, the negative impact of temperature increase in abrasive paste has been reported on the material removal rate, in this study the role of this parameter has been evaluated on AFRM. For this purpose, a new tool equipped with pressure and temperature measuring instruments as well as temperature control device have been designed and fabricated and the temperature changes of the abrasive paste during the process are measured. The process variables in this case have been selected based on the optimum machining conditions corresponding with the maximum material removal rate from the previous study of the authors. The experimental results with new tool show that material removal rate and surface finish of AFM are obtainable by AFRM process. Also no significant increase in paste temperature occurs in AFRM process during effective machining time which is one of the advantages of AFRM. In the case of the process continuation, material removal rate decreases by increasing the temperature of the paste, which shows similar behavior to AFM process.

In this investigation, the material removal rate, tool wear rate and surface integrity obtained by EDM, ultrasonic vibrations assisted EDM and magnetic field assisted EDM were studied and compared with together to show the quality of the effects of applying each of ultrasonic vibrations to tool and magnetic field around gap distance of EDM process on material removal rate, tool wear rate, and surface integrity. According to the results, applying ultrasonic vibrations to tool electrode leads to an increase of 71% in material removal rate of EDM process while applying magnetic fields around gap distance of EDM process leads to an increase of 41% in material removal rate (of course in the best conditions). Also, applying magnetic fields around gap distance of EDM process leads to a decrease of 35% in surface roughness obtained by EDM process while the surface roughness of ultrasonic vibrations assisted EDM is higher than EDM process. Also, the created surface damages in the case of ultrasonic vibrations assisted EDM is the lowest and in the case of EDM process is the highest.

The most important goal of the craftsmen is to maximize the material removal rate while controlling the surface quality. In this article, according to the regression equation obtained from the design of the experiment using the response surface method, to investigate the extent and manner of influence of seven process parameters including, pulse on time, pulse off time, arc off time, gap voltage, wire feeding rate, wire tension and water pressure has been studied on two characteristics of material removal rate and surface roughness using Sobol sensitivity analysis method. The purpose of this research is to select the most optimal parameter in the machining process in order to increase the material removal rate and reduce the surface roughness. According to the results obtained from the sensitivity analysis, it can be seen that the factor of pulse on time and pulse off time each have an effect of 59% and 28%, respectively, the most effective parameters on the material removal rate, and the parameters of pulse on time and water pressure, respectively, with 81% and 18% influence are the most effective parameters on surface roughness.

Rotational abrasive flow machining process (RAFM) is one of the modern surface polishing processes where in the material removal in micro and nano sizes is performed by tiny abrasive particles. Rotational abrasive flow machining is very effective in finishing of complex internal and external surfaces.in comparison with other finishing methods. In this study, the rotational abrasive flow machining process has been investigated in polishing of AISI H 13 hot work steel. The main objectives of workpiece rotation was increasing the material removal rate and decreasing the surface roughness of workpiece. So the effects of rotational speed and hardness of workpiece and the mesh size of abrasive particles as input variables on the output parameters including surface roughness and material removal rate have been studied. The results showed that applying of rotational speed of workpiece leads to higher material removal rate and lower surface roughness. Furthermore, the material removal rate is decreased and surface roughness is improved by increasing the mesh size of abrasive particles. Also, increasing the hardness of workpiece leads to decreasing the material removal rate, and in similar cutting conditions, the surface of workpiece with more hardness is better polished in comparison with the surface of workpiece with lower hardness.

Lapping process is one of the most important polishing processes in order to achieve a flat surface. In this paper, effects of parameters such as abrasive particle size, abrasive particles concentration in slurry, and lapping pressure on material removal rate, flatness and surface roughness were investigated in single sided lapping of flat workpieces made of 440c steel. To conduct experiments, Lapmaster 15 lapping machine has been exerted. The most important problem in lapping process is the low material removal rate which cause increase cost and production time. Therefore, in the lapping process, the selection of conditions that in addition to the production of pieces with geometric accuracy and surface roughness needed have a high material removal rate, is very important. In this paper, for the first time, the material removal rate, surface roughness and flatness lapped pieces have been optimized using non-dominated sorting genetic algorithm II (NSGA II) and, the Pareto optimal solutions were obtained. The results show that NSGA II is a useful and powerful tool for optimizing the material removal rate, surface roughness and flatness lapped pieces. Using this optimization algorithm, pieces with surface roughness and flatness requirements can be produced at high material removal rate. As a result, with this optimization algorithm, in addition to creating optimal quality parts, the production cost and time are reduced.