The Identification of Amplitude and Phase in Imbalance Mass of Grinding Wheel

2011 ◽  
Vol 487 ◽  
pp. 391-395
Author(s):  
Suo Xian Yuan ◽  
Z.L. Guan
Keyword(s):  
Rotational Speed ◽  
Basic Concept ◽  
Dynamic Balance ◽  
Vibration Signal ◽  
Grinding Wheel ◽  
Periodic Signal

Vibration signal produced by imbalance of grinding wheel is a periodic signal that has a same frequency with rotational speed. To identify the signal accurately is premise of balance for grinding wheel. This paper introduces the composition and basic concept of vibration signal in grinding wheel and further studies how to identify process and calculate about this vibration signal. It will provide theory evidence for grinding wheel’s dynamic balance.

Grinding Wheel Dynamic Balance Weight Type System Based on the Self-Optimal Fuzzy Control

2013 ◽  
Vol 834-836 ◽  
pp. 1360-1364
Author(s):  
Hai Tao Ma ◽  
Shu Fan Ma ◽  
Ying Yu ◽  
Feng Chen
Keyword(s):  
Control System ◽  
Fuzzy Controller ◽  
Dynamic Balance ◽  
Type System ◽  
Vibration Signal ◽  
Grinding Wheel ◽  
Balance Principle ◽  
Mathematical Mode ◽  
Control Rules ◽  
Automatic Adaptation

.Grinding wheel as the research object in this paper and aim at the vibration signal use the weight balance principle to balance the centrifugal force caused by the eccentric whee. Designed a kind of self-optimization fuzzy controller, through online optimization correction factor realized the control rules of self-adjustment and self-improvement. Not only solved the problem of relying on the Precise mathematical mode as the conventional control system,but also make the control system has automatic adaptation for the changes of the object properties.Experimental results show that:the effect of the correct balance amount and the grinding wheel unbalance correction offset is good, the vibration drop rate reached 93.2%, has played a good role in inhibition of unbalance, the grinder vibration quantity significantly reduced and improved the performance of the control system.

scholarly journals Optimization of Wet Grinding Conditions of Sheets Made of Stainless Steel

2020 ◽  
Vol 4 (4) ◽  
pp. 114
Author(s):  
Akira Mizobuchi ◽  
Atsuyoshi Tashima
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Rotational Speed ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Steel Sheets ◽  
Wet Grinding ◽  
Grinding Fluid ◽  
Dry Grinding ◽  
Grinding Conditions

This study addresses the wet grinding of large stainless steel sheets, because it is difficult to subject them to dry grinding. Because stainless steel has a low thermal conductivity and a high coefficient of thermal expansion, it easily causes grinding burn and thermal deformation while dry grinding on the wheel without applying a cooling effect. Therefore, wet grinding is a better alternative. In this study, we made several types of grinding wheels, performed the wet grinding of stainless steel sheets, and identified the wheels most suitable for the process. As such, this study developed a special accessory that could be attached to a wet grinding workpiece. The attachment can maintain constant pressure, rotational speed, and supply grinding fluid during work. A set of experiments was conducted to see how some grinding wheels subjected to some grinding conditions affected the surface roughness of a workpiece made of a stainless steel sheet (SUS 304, according to Japanese Industrial Standards: JIS). It was found that the roughness of the sheet could be minimized when a polyvinyl alcohol (PVA) grinding wheel was used as the grinding wheel and tap water was used as the grinding fluid at an attachment pressure of 0.2 MPa and a rotational speed of 150 rpm. It was shown that a surface roughness of up to 0.3 μm in terms of the arithmetic average height could be achieved if the above conditions were satisfied during wet grinding. The final surface roughness was 0.03 μm after finish polishing by buffing. Since the wet grinding of steel has yet to be studied in detail, this article will serve as a valuable reference.

scholarly journals Experimental Research on the Influence of Working Conditions on Vibration and Temperature Rise of Si3N4 Full-Ceramic Bearing Motors

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Zhongxian Xia ◽  
Yuhou Wu ◽  
Hua Wei ◽  
Kexuan Ren ◽  
Longfei Gao ◽  
...  
Keyword(s):  
Working Conditions ◽  
Temperature Rise ◽  
Rotational Speed ◽  
Stable State ◽  
Vibration Signal ◽  
Spindle Motor ◽  
Normal Operation ◽  
Vibration Velocity ◽  
Ceramic Bearing ◽  
Lubrication Conditions

Working conditions such as lubrication, preload, and rotational speed have important influence on vibration and temperature rise of the spindle motor. In this study, controlled variable experiments are carried out on the silicon nitride (Si3N4) full-ceramic ball bearing and steel bearing of the same type, and the vibration signal characteristics and temperature rise of the spindle motor are tested and analysed, by changing the lubrication conditions, preloads, and rotational speeds of the spindle motor. Through the research, it is found that as the rotational speed increases, the vibration velocity of the Si3N4 full-ceramic bearing spindle motor under different preloads and lubrication conditions shows an overall increasing trend; kurtosis generally presents a downward trend and gradually flattens, indicating that although the vibration velocity increases at high speeds, the vibration signal shows a relatively stable state. As the rotational speed increases, the difference of vibration velocity under the condition of applying preload and no preload decreases, indicating that the influence of preload on the vibration of full-ceramic bearing spindle motor decreases with the increase in rotational speeds. At the same time, it is found that fr and 5fr have greater impact on the vibration of full-ceramic bearing spindle motor, where fr is the frequency of the bearing in normal operation, and 5fr is 5 times of the normal operating frequency. Lubrication conditions have little effect on the temperature rise of full-ceramic bearing spindle motor, and the temperature rise under nonlubricated conditions is even slightly lower than that under grease lubrication conditions. The research results show that the vibration velocity and temperature rise of Si3N4 full-ceramic bearing spindle motor are less than those of steel bearing with the same type, indicating that full-ceramic bearing has better performance than steel bearing under the same working conditions.

Experimental Investigation of the Material Removal Rate in Grinding of Calcified Plaque by Rotational Atherectomy

2021 ◽  
Author(s):  
Xinxiao Li ◽  
Patrick Chernjavsky ◽  
Katerina Angjeli ◽  
Sola Hoffman ◽  
Sara Frunzi ◽  
...  
Keyword(s):  
Material Removal Rate ◽  
Rotational Speed ◽  
Material Removal ◽  
Removal Rate ◽  
Ground Surface ◽  
Rotational Atherectomy ◽  
Grinding Wheel ◽  
Complication Rates ◽  
Calcified Plaque ◽  
Luminal Area

Abstract Rotational atherectomy (RA) utilizes a high-speed, metal-bonded diamond-abrasive grinding wheel to remove the calcified atherosclerotic plaque inside arteries, restore blood flow, and treat cardiovascular diseases. RA operational guidelines have been clinically investigated to improve clinical outcomes and reduce complication rates, but are still in lack of consensus. Particularly, the effect of the grinding wheel rotational speed on plaque material removal rate (MRR) is unclear. This study experimentally investigates the RA MRR over a range of wheel rotational speeds based on a vascular simulator with a calcified plaque surrogate. The MRR, presented as the luminal area gain, with the increase of the number of grinding passes, was measured at the rotational speed of 120,000, 150,000, and 180,000 rpm. The luminal area was characterized via microscopy and image processing. The ground surface morphology and surface roughness at different rotational speeds were investigated. The results showed that a higher rotational speed led to a higher MRR and a smoother ground surface. This observation is significant for RA clinical guideline improvement.

Grinding Marks in Back Grinding of Wafer with Outer Rim

2020 ◽  
Vol 234 (16) ◽  
pp. 3195-3206
Author(s):  
Xianglong Zhu ◽  
Yu Li ◽  
Zhigang Dong ◽  
Renke Kang ◽  
Shang Gao ◽  
...  
Keyword(s):  
Simulation Model ◽  
Process Parameters ◽  
Rotational Speed ◽  
Wheel Speed ◽  
Silicon Wafers ◽  
New Method ◽  
Grinding Wheel ◽  
Abrasive Grains ◽  
Grinding Parameters ◽  
The Relationship

Back Grinding of Wafer with Outer Rim (BGWOR) is a new method for carrier-less thinning of silicon wafers. In this paper, the simulation model of grinding marks of wafer in BGWOR was developed. With the model, the relationship between process parameters, including wheel rotational speed, wafer rotational speed, wheel infeed rate, spark out time and the protruding height of the abrasive grains in the grinding wheel, and grinding marks was discussed. Reasonable grinding parameters to control the grinding marks were also proposed. The model was verified by the experiments of BGWOR. The results showed that: (1) The pattern of the grinding marks of the wafers in BGWOR was depended on the grinding wheel rotational speed, the wafer rotational speed, the wheel infeed rate, the spark out time and the protruding height of the abrasive grains on the grinding wheel; (2) The angle between two adjacent grinding marks changes as the variation of the wheel rotational speed and wafer rotational speed; (3) The grinding marks density can be controlled by selecting the proper ratio of wheel speed to wafer speed. The depth of grinding marks can be reduced by increasing the spark out time and reducing the protruding height of the abrasive grains.

Design of Surface Finish Using Synchronous Process of Grinding and Electrochemical Finishing

2007 ◽  
Vol 359-360 ◽  
pp. 259-263
Author(s):  
Pai Shan Pa
Keyword(s):  
Surface Roughness ◽  
Flow Rate ◽  
Surface Finish ◽  
Feed Rate ◽  
Rotational Speed ◽  
Machining Process ◽  
Grinding Wheel ◽  
High Rotational Speed ◽  
Plate Electrode ◽  
Electrochemical Finishing

In order to elevate the efficiency of the surface finish to reach the fast improvement of the surface roughness of the workpiece, so as to reduce the residual stress on the surface efficiently. The present study discusses the surface after traditional machining, of which the plane surface used a design of finish tool includes an electrode and a nonconductive grinding wheel to execute the synchronous process of grinding and electrochemical finishing. The electrode form and the machining process are obviously different from electrochemical grinding (ECG). In the experiment, the design electrode is used with continuous and pulsed direct current. The controlled factors include die material, and chemical composition and concentration of the electrolyte. The experimental parameters are flow rate of electrolytes, position of plate electrode, electrode thickness, electrode rotational speed, electrical current rating, feed rate of workpiece, and pulsed period. The experimental results show that the supply of current rating is near concern with the position and thickness of the plate electrode. The use of large electrolytic flow rate and thick electrode is advantageous to the finish effect. High rotational speed of finish tool produces better polishing. The finishing effect is better with longer off-time because discharge of polishing dregs becomes easier. Higher current rating with quicker workpiece feed rate effectively reaches the fast improvement of the surface roughness of the workpiece is recommend in current study.

Research on Dynamic Balance of Grinding Wheel Spindle

2011 ◽  
Vol 487 ◽  
pp. 482-485
Author(s):  
Qin Yuan Zhou ◽  
Zhi Xiong Zhou ◽  
Y. Li
Keyword(s):  
High Precision ◽  
Critical Speed ◽  
Dynamic Balance ◽  
New Method ◽  
Grinding Wheel ◽  
Speed Range ◽  
Rotor Dynamic ◽  
Dynamic Unbalance ◽  
Quality Surface

In this paper, grinding wheel spindle of high precision CNC is researched. Mathematics - mechanical mode of dynamic balance of grinding wheel is established on the principle of rotor dynamic balance. New method of critical speed of grinding wheel is proposed, and verified by testing the reasonableness. And, dynamic unbalance of grinding wheel spindle of high precision CNC is studied on quality surface. These studies provide theoretical direction for balance speed range and the accurate level.

scholarly journals An Instantaneous Engine Speed Estimation Method Using Multiple Matching Synchrosqueezing Transform

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Youyong Liu ◽  
He Wen ◽  
Zongying Ding ◽  
Lei Xu ◽  
Hongjiang Chen ◽  
...  
Keyword(s):  
Fundamental Frequency ◽  
Rotational Speed ◽  
Vibration Signal ◽  
Frequency Resolution ◽  
Estimation Methods ◽  
Noise Robustness ◽  
Speed Estimation ◽  
Automobile Engine ◽  
Engine Vibration ◽  
Synchrosqueezing Transform

Instantaneous rotational speed measurement of the engine is crucial in routine inspection and maintenance of an automobile engine. Since the contact measurement of rotational speed is not always available, the vibration measurement has been used for noncontact rotational speed estimation methods. Unfortunately, the accuracy of the noncontact estimation methods by analyzing engine vibration frequency is not satisfactory due to the influence of noise and the strong nonstationary characteristic of the vibration signal. To overcome these problems, based on the multiple matching synchrosqueezing transform (MSST) (MMSST, improved MSST with multiple squeeze operations), a novel noncontact method is proposed to accurately estimate the instantaneous rotational speed of automobile engine in this paper. Firstly, a MMSST is proposed to process the vibration signal to obtain a concentrated time-frequency (TF) representation. Secondly, the instantaneous frequency (IF) detection algorithm is employed to extract the fundamental frequency from the TF result. Finally, the rotational speed of the engine is calculated according to the relationship between the fundamental frequency and rotational speed. Results from numerical simulations and test on real engine have proven that the proposed method can obtain much higher frequency resolution and more precise IF estimation of the engine vibration signal and more accurate rotational speed estimation result compared with the MSST method. Furthermore, the proposed method is verified to have a stronger noise robustness and can provide satisfactory estimation results for engine vibration signal containing nonlinear frequency-modulated components.

Investigation on Machinery Control System Based on Fuzzy PID Control Technology

2012 ◽  
Vol 203 ◽  
pp. 130-134
Author(s):  
Kuan Luo
Keyword(s):  
Control System ◽  
Pid Control ◽  
Rotational Speed ◽  
Basic Concept ◽  
Electrical Machine ◽  
Control Technology ◽  
Fuzzy Pid ◽  
Fuzzy Pid Control ◽  
Rotational Speed Control ◽  
System Designs

This review gives the basic concept、mechanism、and algorithm of automatic controlling theory，puts forward some views for the design of automatic control system，designs a new model for the rotational speed control of the stepping electrical machine.

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