Wyniki wyszukiwania - Biblioteka Nauki

1

Modeling of Vibration Behaviors of Turning Machining with the Constant Surface Speed Effect

100%

Royandi M. A. , Effendi I. A. , Ibrahim B. , Hung J. P.

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tom Vol. 15, no 3

134--145

EN

Turning machining is a complex process in which many variables can influence the desired results. Among those variables, cutting tool vibration and cutting force greatly affect the precision of the workpiece and the tool life. While the tool vibration and cutting force in feeding are primarily determined by cutting speed, feed rate, and depth of cut as well as the dynamic characteristics of the machining system. This paper presents an analytical modeling approach to investigate the effects of machining conditions based on the governing equation of the machining system. The machining behaviors under different conditions were simulated by Simulink block diagram. Basically, the cutting speed is considered the parameter dominating the vibration behavior and hence is served as the primary input for the simulation. The effectiveness of constant surface speed (CSS mode) or function G96 in the turning process was further examined through comparisons of the variations of vibration and cutting force generated in feeding with different conditions.

2

PC controlled turning tool

100%

Mikołajczyk T. , Kamieniecki Ł.

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tom Vol. 7, no 3

199-204

EN

Design of PC controlled turning tool is presented in paper. Tool placed in the guides was driving using the stepper motor and a screw cooperating with the nut joined with the tool. To control of the tool was used PC with the step motor interface connected to the LPT port. Mounted to the holder tool allows machining shape surface using the universal lathe.

3

Skrawanie toczeniem elementów o przekroju niekołowym

75%

Rusinek R. , Warmiński J.

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tom nr 4

30-33

PL

W pracy przedstawiono wyniki badań eksperymentalnych toczenia skrawaniem elementu metalowego o prostokątnym przekroju poprzecznym. Zaproponowano matematyczny opis takiego układu w postaci równań różniczkowych zawierających wzbudzenie parametryczne. W badaniach doświadczalnych wykazano związek pomiędzy częstością i amplitudą drgań a prędkością wrzeciona.

EN

Analysis of a turning process of a workpiece with a rectangular cross section is presented in the paper. Results of experimental investigations are shown. A mathematical model of parametric vibrations caused by stiffness changing is also proposed. A connection between vibrations frequency and rotational speed of a chuck is proved on the basis of experiment.

4

System Identification and Model Predictive Control of the Chatter Phenomenon in Turning Process

63%

Karimipour A. , Emami M.

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2019

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tom Vol. 13, no 3

217--228

EN

Chatter is a series of unwanted and extreme vibrations which frequently happens during different machining processes and impose variety of adverse effects on the machine-tool and surface finish. Chatter has two main types namely forced-chatter and self-existed chatter. The forced-chatter has an external cause; however, self-exited chatter has no external stimuli, rather it is created due to the phase difference between the previous and current waves on the surface of the workpiece. Due to the self-generative nature of this type of chatter, its recognition and prevention is much more difficult. For preventing self-exited chatter its model should be available first. The chatter is usually simulated as a one degree of freedom mass-spring-damper model with unknown parameters that they should be determined somehow. In this paper, the parameters of the tool equation of motion i.e. mass, damping, and stiffness coefficients of the system are predicted through a wavelet-based method online, and then based on the achieved parameters, the system is controlled via Model Predictive Control (MPC) approach. For the validation, the algorithm is applied to 25 different experimental tests in which the acceleration of the tool and cutting force are measured via an accelerometer and a dynamometer. By investigation of the SLDs generated by the predicted parameters, the presented system identification method is validated. Also, it is shown that the chatter vibration is completely restrained by means of MPC. For investigation of the MPC performance, MPC algorithm is compared with PID controller and simulations has indicated a much stronger performance of MPC rather than PID controller in terms of vibration attenuation and control effort.

5

Zastosowanie sieci neuronowych do modelowania odksztalcen przedmiotu obrabianego podczas toczenia

63%

Jóźwik J. , Lipski J.

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tom nr 4(16)

30-39

PL

W artykule wskazano na szerokie możliwości modelowania procesów skrawania za pomocą strategii samouczenia. Zaprezentowano model predykcji sumarycznych odkształceń przedmiotu obrabianego za pomocą sztucznych sieci neuronowych. Badania i analizy przeprowadzono na przykładzie toczenia ortogonalnego tulei cienkościennej, poddanej działaniu ciepła i sił w procesie skrawania.

EN

In this paper has been to shown wide possibility modeling of cutting process by self-teaching strategy. Hear have been presented neural network model of workpiece summary deformations. Research and analyzes have been shown based on example orthogonal turning of thin-walled sleeve to expose it on action of heat and cutting forces.

6

Turning-form electrode in ultrasonic-aided electrochemical finishing

51%

Pa P. S.

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tom Vol. 21, nr 2

77-80

EN

Purpose: The ultrasonic-aided electrochemical finishing following traditional turning by a turning-form electrode for several die materials is demonstrated. Design/methodology/approach: A guide line for the design process is followed a scientific method including the design requirement, design development, detail design, and experimental analysis is adopted in the current study. The proposed design of turning-form electrode combined with the ultrasonic-aided electrochemical finishing is presented. Findings: Smaller end radius and smaller declination angle are associated with higher current density and provides larger discharge space and better polishing effect. The plate-shape electrode with small end radius and decreasing the surface area of top-view performs the best. The ultrasonic assistance can avoid the difficulty of dreg discharge in the electrochemical finishing, thus increasing the finishing effect. Research limitations/implications: The potential for electrode design and using ultrasonic energy transmitted to the electrolyte to assist discharging dregs out of electrode gap during the electrochemical finishing is yet to be explored. Practical implications: This process can be used for various turning operations including end turning, form turning, and flute and thread cutting. Through simple equipment attachement, the electrochemical finishing can follow the cutting on the same machine and chuck. Originality/value: It is great contribution that the ultrasonic-aided electrochemical finishing after turning process just needs quite short time than manual or machine finishing to make the surface of workpiece smooth and bright. An effective and low-cost finishing method after turning process is presented.

7

Multiobjective optimization of multipass turning machining process using the Genetic Algorithms solution

51%

Amiolemhen P. E. , Eseigbe J. A.

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tom Vol. 3, No 2

97--108

EN

The study involves the development of multi-objective optimization model for turning machining process. This model was developed using a GA - based weighted-sum of minimum production cost and time criteria of multipass turning machining process subject to relevant technological/practical constraints. The results of the single-objective machining process optimization models for the multipass turning machining process when compared with those of multi-objective machining process model yielded the minimum production cost and minimum production time as $5.775 and 8.320 min respectively (and the corresponding production time and production cost as 12.996 min and $6.992, respectively), while those of the multi-objective machining process optimization model were $5.841and 9.097 min. Thus, the multi-objective machining process optimization model performed better than each of the single-objective model for the two criteria of minimum production cost and minimum production time respectively. The results also show that minimum production time model performs better than the minimum production cost model. For the example considered, the multi-objective model gave a lower production time of 30.0% than the corresponding production time obtained from the minimum production cost model, while it gave a lower production cost of 16.46% than the corresponding cost obtained by the minimum production time model.