A New Type of Controllable Mechanical Press: Motion Control and Experiment Validation

2004 ◽  
Vol 127 (4) ◽  
pp. 731-742 ◽  
Author(s):  
W. Z. Guo ◽  
K. He ◽  
K. Yeung ◽  
R. Du
Keyword(s):  
Motion Control ◽  
Metal Forming ◽  
Variable Speed ◽  
The Press ◽  
Experiment Validation ◽  
Mechanical Press ◽  
New Type ◽  
Key Dimensions ◽  
Angular Displacements ◽  
The Relationship

This paper is the second part of our study on designing a new type of metal forming press. In the first part of the study (Du, R., and Guo, W. Z., 2003, ASME J. Mech. Des., 125(3), pp. 582–592), a new controllable mechanical press is introduced that consists of a large constant-speed motor (CSM) and a small variable-speed servomotor (VSM). The CSM provides up to 80% of the power while the VSM tunes the motion of the ram. This new design has a number of advantages: it is flexible (i.e., its ram motion is programable), fast (its speed is limited only by the mechanical motion), and energy efficient (the CSM can use a large flywheel to ease the large instantaneous metal forming force). This paper focuses on the motion control and experiment validation. First, the inverse kinematics is presented, which gives the relationship between the ram travel and (i) the input angular displacements, velocities, and accelerations of the two motors. Next, a trajectory-planning method is given. Then, the sensitivity analysis is carried out, which helps to determine the key dimensions of the press and the error compensation scheme. Finally, two experiments are shown to demonstrate that the new press can accomplish different tasks.

FEM Simulation of a Friction Testing Metliod Based on Combined Forward Conical Can-Backward Straight Can Extrusion

1998 ◽  
Vol 120 (4) ◽  
pp. 716-723 ◽  
Author(s):  
Tamotsu Nakamura ◽  
Niels Bay ◽  
Zhi-Liang Zhang
Keyword(s):  
Friction Coefficient ◽  
Metal Forming ◽  
Fem Simulation ◽  
Fem Analysis ◽  
Rigid Plastic ◽  
Workpiece Material ◽  
Testing Method ◽  
Friction Testing ◽  
Mechanical Press ◽  
The Relationship

A new friction testing method based on combined forward conical can-backward straight can extrusion is proposed in order to evaluate friction characteristics in severe metal forming operations. By this method the friction coefficient along the conical punch surface is determined knowing the friction coefficient along the die wall. The latter is determined by a combined forward and backward can extrusion of straight cans. Calibration curves determining the relationship between punch travel, can heights, and friction coefficient for the two tests are calculated based on a rigid-plastic FEM analysis. Experimental friction tests are carried out in a mechanical press with aluminium alloy A6061 as the workpiece material and different kinds of lubricants. They confirm that the theoretical analysis results in reasonable values for the friction coefficient.

On the Design of a Novel Controllable Mechanical Metal Forming Press Based on 2-DOF Planar Mechanism

2005 ◽  
Author(s):  
Zhenlin Jin ◽  
Kai He ◽  
R. Du
Keyword(s):  
Metal Forming ◽  
Energy Efficient ◽  
Experimental Testing ◽  
Ball Screw ◽  
Distribution Analysis ◽  
Planar Mechanism ◽  
Step Motion ◽  
The Press ◽  
New Type ◽  
And Control

It is known that the punch motion has a significant effect on sheet metal stamping operations. For example, for deep drawing operations long dwelling is desirable. For blanking operations, on the other hand, the two-step motion can reduce the noise [1]. However, the controlled punch motion cannot be realized using conventional mechanical presses, which has the advantage of being energy efficient, fast and easier to make / maintain. Servo mechanical presses solved some of the problems, but are not energy efficient (because they cannot use flywheels as the conventional mechanical presses). Following our previous research [2–4], this paper presents a new type of controllable mechanical press. It is a 2-DOF planar mechanism driven by a large constant speed motor (which takes 75% of the load) and a small servomotor (which takes 25% of the load). Though, unlike the first design, the new design uses the servomotor to drive a ball screw instead of a crank, which makes building the press simpler and controlling the press easier. The paper describes various issues in designing and controlling the press including (a) Kinematics and inverse kinematics; (b) Static force distribution analysis and parameter design; and (c) Punch motion programming and control. A 250 KN prototype has been built and the experimental testing results confirm that the press is working properly. Comparing to the existing technology, the new press is controllable and energy efficient. It is expected that it will have a significant value to the metal forming industry.

scholarly journals Sodium Metasilicate Cemented Analogue Material and Its Mechanical Properties

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Songlin Yue ◽  
Yanyu Qiu ◽  
Pengxian Fan ◽  
Pin Zhang ◽  
Ning Zhang
Keyword(s):  
Complex Geometry ◽  
Sodium Metasilicate ◽  
Raw Material ◽  
Fine Aggregate ◽  
Regression Equations ◽  
Deformation And Failure ◽  
Orthogonal Experiments ◽  
Low Modulus ◽  
New Type ◽  
The Relationship

Analogue material with appropriate properties is of great importance to the reliability of geomechanical model test, which is one of the mostly used approaches in field of geotechnical research. In this paper, a new type of analogue material is developed, which is composed of coarse aggregate (quartz sand and/or barite sand), fine aggregate (barite powder), and cementitious material (anhydrous sodium silicate). The components of each raw material are the key influencing factors, which significantly affect the physical and mechanical parameters of analogue materials. In order to establish the relationship between parameters and factors, the material properties including density, Young’s modulus, uniaxial compressive strength, and tensile strength were investigated by a series of orthogonal experiments with hundreds of samples. By orthogonal regression analysis, the regression equations of each parameter were obtained based on experimental data, which can predict the properties of the developed analogue materials according to proportions. The experiments and applications indicate that sodium metasilicate cemented analogue material is a type of low-strength and low-modulus material with designable density, which is insensitive to humidity and temperature and satisfies mechanical scaling criteria for weak rock or soft geological materials. Moreover, the developed material can be easily cast into structures with complex geometry shapes and simulate the deformation and failure processes of prototype rocks.

A Preliminary Test of the Impact of De-Globalization on MNC Performance

2021 ◽  
Vol 17 (2) ◽  
pp. 412-428
Author(s):  
Hilla Peretz ◽  
Michael J. Morley
Keyword(s):  
Organizational Context ◽  
Preliminary Test ◽  
Organizational Level ◽  
Institutional Fit ◽  
Preliminary Examination ◽  
Negative Effect ◽  
Key Dimensions ◽  
Using Data ◽  
The Impact ◽  
The Relationship

ABSTRACTWe offer a preliminary examination of whether national and organizational level contexts amplify or reduce the effects of de-globalization on the performance of MNCs. Theoretically, we borrow ideas from both event system theory and institutional fit to propose a model explicating key dimensions of the relationship between de-globalization, national and organizational context, and MNC performance. We then test our ideas using data assembled from 283 MNCs in 20 countries. We find that while de-globalization has a negative effect on MNC performance, national and organizational level contextual endowments do moderate this relationship. We discuss some implications of our findings and highlight attendant limitations.

CAD AND CAE TECHNOLOGIES OF A NOVEL PLANE SIX-BAR SWAYING MACHINE

2008 ◽  
Vol 07 (01) ◽  
pp. 65-67
Author(s):  
CHANGPING ZOU ◽  
LI DU ◽  
XIANDE HUANG
Keyword(s):  
High Pressure ◽  
Kinetic Analysis ◽  
Rotational Speed ◽  
Preliminary Analysis ◽  
Unit Weight ◽  
The Novel ◽  
Parameterized Modeling ◽  
New Type ◽  
Working Principle ◽  
Key Dimensions

A new type of six-bar swaying machine was put forward, which is an ingenious combination of plane multi-bar mechanism and high pressure oil cylinder. Preliminary analysis shows that this machine has many advantages, such as the torque produced by its unit weight, its small size, its light deadweight, etc. Thus it can be applied to situations that need swaying mechanism with low rotational speed and great torque. Firstly, the mechanism composition and working principle of the swaying machine were introduced. Secondly, parameterized modeling of the mechanism was carried out by utilizing software ADAMS. Then kinematic analysis and kinetic analysis were completed by using ADAMS. Finally, key dimensions were adjusted according to kinetic analysis. These tasks are believed to be beneficial to the development of the novel transmission.

scholarly journals The Denouncers: Populism and the Press in Venezuela

2016 ◽  
Vol 49 (1) ◽  
pp. 1-27 ◽  
Author(s):  
ROBERT SAMET
Keyword(s):  
Latin America ◽  
Making Sense ◽  
Everyday Practices ◽  
The Press ◽  
The Everyday ◽  
The Media ◽  
The Relationship ◽  
Recent Attention

AbstractDespite recent attention to the relationship between the media and populist mobilisation in Latin America, there is a misfit between the everyday practices of journalists and the theoretical tools that we have for making sense of these practices. The objective of this article is to help reorient research on populism and the press in Latin America so that it better reflects the grounded practices and autochthonous norms of the region. To that end, I turn to the case of Venezuela, and a practice that has been largely escaped attention from scholars – the use of denuncias.

Prediction of Springback in Metal Forming of Diaphragm of Automotive Horn Based on BPANN

2010 ◽  
Vol 139-141 ◽  
pp. 594-599
Author(s):  
Yan Qiu Zhang ◽  
Shu Yong Jiang ◽  
Yu Feng Zheng
Keyword(s):  
Young’S Modulus ◽  
Metal Forming ◽  
Young's Modulus ◽  
Steel Strip ◽  
Back Propagation ◽  
Spring Steel ◽  
Yield Ratio ◽  
Punch Radius ◽  
Cold Rolled ◽  
The Relationship

The spring steel strip 50CrVA which is cold rolled was applied to manufacture the diaphragm of the automotive horn by means of sheet metal forming. The combination of the experiments with back-propagation artificial neural network (BPANN) is used to solve the springback problem of the diaphragm. Experiments have shown that a 4-8-1 BPANN is able to predict the springback of the diaphragm successfully, and the network is able to model the relationship between the springback of the diaphragm and the process parameters rationally. BPANN simulation results and experimental ones have shown that the springback of the diaphragm is particularly influenced by such parameters as blank thickness, Young’s modulus, punch radius and yield ratio. Furthermore, the springback of the diaphragm decreases with the increase of blank thickness and Young’s modulus, but increases with the increase of punch radius and yield ratio.

Design and analysis of a novel seven-bar mechanical servo press with dual motors inputs

2016 ◽  
Vol 231 (20) ◽  
pp. 3855-3865
Author(s):  
Chen Liu ◽  
Sheng-Dun Zhao ◽  
Jing-Xiang Li
Keyword(s):  
Metal Forming ◽  
Theoretical Study ◽  
High Capacity ◽  
High Ratio ◽  
Measured Data ◽  
Servo Motor ◽  
Symmetric Structure ◽  
Servo Press ◽  
The Press ◽  
Dynamic Analyses

This paper proposes a novel high capacity servo press system with two servo motor inputs and high ratio force amplifier mechanism for metal forming. First, the press structure was expressed. The force amplifier was made of seven-bar mechanism which possesses quick-return character and high ratio force amplifier. The symmetric structure balanced the force in horizontal direction, and dispersed the forces on two transmission routes. In theoretical study of the new structure, kinematic and dynamic analyses were obtained by examining the geometry of the structure. The performance of press was discussed by example demonstration. Finally, the kinematic experiments and metal forming experiments were carried out on the prototype machine by using grating scale system. The measured data match the theoretical calculation well, which validates the feasibility of this new press mechanism.

Thermodynamic Performance of an Actual Thermo-Acoustic Refrigeration Micro-Cycle

2012 ◽  
Vol 614-615 ◽  
pp. 64-68
Author(s):  
Tuo Wang ◽  
Feng Wu ◽  
Jin Hua Fei ◽  
Ming Fang Liu
Keyword(s):  
Coefficient Of Performance ◽  
Pressure Amplitude ◽  
Cooling Load ◽  
Acoustic Effect ◽  
Thermodynamic Performance ◽  
Monotonically Increasing Function ◽  
Analytic Expressions ◽  
New Type ◽  
The Relationship ◽  
Increasing Function

Thermo-acoustic refrigerator is a new type of engine, which is based on the thermo-acoustic effect. A new model which expresses as an ellipse in pressure-volume diagram is established to investigate the thermodynamic performance of an actual thermo-acoustic refrigeration micro-cycle. The demarcation points of endothermic processes and exothermic processes in the actual micro-cycle are found. The analytic expressions of the dimensionless cooling load and the coefficient of performance (COP) are deduced. The relationship between the dimensionless cooling load and the COP are investigated by numerical examples. The results show that the dimensionless cooling load is a monotonically increasing function of the COP and the pressure amplitude.

Experimental study on the relationship between the friction coefficient and interference in locomotive axle press-fitting

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ting Wang ◽  
Hanfei Guo ◽  
Jianjun Qiao ◽  
Xiaoxue Liu ◽  
Zhixin Fan
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Friction Pair ◽  
Rolling Stock ◽  
Content Type ◽  
Press Fitting ◽  
The Press ◽  
The Coefficient Of Friction ◽  
The Relationship ◽  
Locomotive Wheels

PurposeTo address the lack of data in this field and determine the relationship between the coefficient of friction and the interference between locomotive wheels and axles, this study evaluates the theoretical relationship between the coefficient of friction and the interference under elastic deformation.Design/methodology/approachWhen using numerical analyses to study the mechanical state of the contacting components of the wheels and axle, the interference between the axle parts and the coefficient of friction between the axle parts are two important influencing factors. Currently, as the range of the coefficient of friction between the wheel and axle in interference remains unknown, it is generally considered that the coefficient of friction is only related to the materials of the friction pair; the relationship between the interference and the coefficient of friction is often neglected.FindingsA total of 520 press-fitting experiments were conducted for 130 sets of wheels and axles of the HXD2 locomotive with 4 types of interferences, in order to obtain the relationship between the coefficient of friction between the locomotive wheel and axle and the amount of interference. These results are expected to serve as a reference for selecting the coefficient of friction when designing axle structures with the rolling stock, research on the press-fitting process and evaluations of the fatigue life.Originality/valueThe study provides a basis for the selection of friction coefficient and interference amount in the design of locomotive wheels and axles.

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