Pulse Sequence Frequency Selection Method of High Frequency Shake-out Machine

Abstract

The pulse sequence frequency is an important control parameter of shake-out machine. Traditionally, the selection is done by trial and error. This method is low in efficiency, wastes energy in repeated impact tests, and the selected pulse frequency reliability is low, so it often fails to get good shake-out effect. Aiming at the shortcomings of the trial and error method, the method of selecting the pulse frequency of air hammer by means of modal analysis and harmonic response analysis of castings is proposed. The value range of frequency is greatly reduced and the optimization efficiency of pulse frequency is improved by means of this method. Introduction The shake-out of complex casting has always been a complex and laborious part in the process of casting cleaning. In the process of shake-out, the choice of the shock pulse frequency is traditionally chosen by trial and error. According to the experience, the traditional method shocks the casting by trial and error method, and then cuts the casting to observe the shakeout effect. But this method is low-efficiency, repeated shock tests waste energy and the reliability of the selected pulse frequency is also low. The shakeout effect is not good. In view of the shortcomings of the above methods, a new method is proposed. The pulse frequency of air hammer is selected by modal analysis and harmonic response analysis. This method improves the efficiency of frequency selection, and the choice of the pulse frequency verified by the practice of the shakeout effect is better. The value range of frequency is greatly reduced and the optimization efficiency of pulse frequency is improved by means of this method. The Working Principle of Shake-out Machine The shake-out machine works by using air hammer to repeatedly shock the castings, at the same time, vibrating the casting by vibrating motor to achieve the purpose of shakeout. The air hammer repeatedly shocks the casting, which corresponds to the sequence of pulses acting on the casting[1]. The structure of the shake-out machine is shown in Fig. 1 (1-Lower machine base; 2-Isolator; 3-Upper machine base; 4-Vibrating motor; 5-Air hammer mounting seat; 6-Air hammer; 7-Clamping fixture; 8-Rubber gasket; 9-Casting placing platform; 10-Pneumatic clamping mechanism )[2]. Different castings require different pulse frequency, thus according to tests to select a different pulse frequency. Spectrum Analysis of Air Hammer Shock Pulse Sequence The air hammer repeatedly shocks the casting, which corresponds to the sequence of pulses acting on the casting. The periodic rectangular pulse sequence with equal intervals is represented by a rectangular pulse sequence function rec(t,T0,τ,A), as shown in Fig. 2. Based on Fourier transform theory[3,4], the spectrum analysis of pulse sequence of shakeout shock force is carried out. The relationship between the time domain parameters and the frequency domain parameters of the shock pulse sequence is obtained. International Conference on Modeling, Analysis, Simulation Technologies and Applications (MASTA 2019) Copyright © 2019, the Authors. Published by Atlantis Press. This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/). Advances in Intelligent Systems Research, volume 168