Friction Forces between Sheet Molding Compound Charge and Mold Cavity Surface in Compression Molding

2011 ◽  
Vol 471-472 ◽  
pp. 733-738 ◽  
Author(s):  
Mahmood M. Shokrieh ◽  
Reza Mosalmani
Keyword(s):  
Friction Force ◽  
Compression Molding ◽  
Molding Pressure ◽  
Cavity Surface ◽  
Hydrodynamic Friction ◽  
Friction Forces ◽  
Molding Compound ◽  
Sheet Molding Compound ◽  
Constant Friction ◽  
Proposed Model

In this study, three relevant friction ‎forces: constant friction force, hydrodynamic friction force and coulomb friction force are ‎considered between sheet molding compound (SMC) charge and contact surface of the mold. The power ‎law model is implemented to propose a model for prediction of hydrodynamic friction as the dominant friction of the SMC compression molding. The proposed model ‎is simple and does not need any extra experimental parameters. Finally, a model has been developed to predict the molding pressure under non-isothermal conditions. The obtained results of the model are in a very good agreement with the experimental data.

Decreasing the cycle time for in‐mold coating (IMC) of sheet molding compound (SMC) compression molding

2019 ◽  
Vol 59 (6) ◽  
pp. 1158-1166 ◽  
Author(s):  
Mohammad S.K. Bhuyan ◽  
Seunghyun Ko ◽  
Maria G. Villarreal ◽  
Elliott J. Straus ◽  
Lee James ◽  
...  
Keyword(s):  
Cycle Time ◽  
Compression Molding ◽  
Molding Compound ◽  
Sheet Molding Compound

Linear Friction Damper Consisted of Cylindrical Block and Inclined Lever (Improvement to Avoid Sprag-Slip Problem and Analytical Model to Verify Cause)

2011 ◽  
Author(s):  
Hideya Yamaguchi ◽  
Hidehisa Yoshida
Keyword(s):  
Analytical Model ◽  
Friction Force ◽  
Friction Damper ◽  
Friction Forces ◽  
Constant Friction ◽  
Linear Friction ◽  
New Type ◽  
Passive Isolation ◽  
Isolation Systems ◽  
Cylindrical Block

For the passive isolation systems, the ordinary friction damper of constant friction force has performance limitations. This is, because the isolation characteristic declines and the displacement remains apart from the equilibrium position after the disturbance disappears, when the friction force is large. It is known that the above drawbacks are improved when the friction force varies depending on the displacement. The authors have proposed a new type of friction damper in our previous paper. This friction damper uses an inclined lever, which contacts the cylindrical block by means of a rotational spring. The angle of inclination of the lever varies together with the displacement of the cylindrical block. Then, the normal and friction forces on the contact surface vary depending on the displacement. However, “Sprag-slip” vibration occurred in some cases in the experiments. This paper investigates the cause of the vibration and a design to prevent it. Then, an analytical model is proposed to simulate the problem and to estimate the effect of improvement.

Effects of carriage flexibility on friction force in linear ball guides

2021 ◽  
pp. 1-28
Author(s):  
Van-Canh Tong ◽  
Gyungho Khim ◽  
Seong-Wook Hong
Keyword(s):  
Friction Force ◽  
External Load ◽  
Rolling Friction ◽  
Conventional Model ◽  
Friction Forces ◽  
Elastic Hysteresis ◽  
Contact Loads ◽  
Proposed Model ◽  
Ball Contact ◽  
Hysteresis Friction

Abstract This paper presents the effects of carriage flexibility on the friction force in linear ball guides, which includes hydrodynamic rolling friction, elastic hysteresis friction, slip friction, and drag friction. To this end, we developed a computational model for the friction force in linear ball guides that accounts for the carriage flexibility. The model was validated through experiments, and the results prove that it provides more accurate friction-force estimates than the conventional model under the assumption of a rigid carriage. Subsequently, we examined the effects of external load, preload, and speed on the friction force. Among several friction components, hydrodynamic rolling friction makes a major contribution to the total friction force. Ball contact loads, which significantly vary with carriage flexibility, were found to influence the hydrodynamic rolling, elastic hysteresis, and slip friction forces. The proposed model considering carriage flexibility in linear ball guides is expected to find use in the design and operation of linear-ball-guide systems.

Simulation of Molding Flow of Sheet Molding Compound in Complicated Dies

2008 ◽  
Vol 575-578 ◽  
pp. 422-426
Author(s):  
Qi Lin Mei ◽  
Shi Lin Yan ◽  
Zhi Xiong Huang ◽  
Jian Juan Guo
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Control Volume ◽  
Compression Molding ◽  
Technological Parameters ◽  
Molding Compound ◽  
Sheet Molding Compound ◽  
Molding Flow ◽  
Control Volume Finite Element

Based on generalized Hele-Shaw(GHS) model, numerical simulation of compression-molding flow of sheet molding compound (SMC) in complicated dies is realized by control volume/finite element method (CV/FEM). Finite element computing and post analysis programs have been written. The flow fronts of SMC charge during compression molding are tracked, and the time needed of mold filling in complicated dies is predicted. The results of simulation are helpful for the placement of SMC charge, the design of mold and the optimization of technological parameters.

Preparation and Characterization of a Low Density and Low Pressure Sheet Molding Compound

2020 ◽  
Vol 1003 ◽  
pp. 98-105
Author(s):  
Min Xian Shi ◽  
Chuang Dong ◽  
Yong Zhang ◽  
Zhi Xiong Huang
Keyword(s):  
Thermal Conductivity ◽  
Flexural Strength ◽  
High Strength ◽  
Low Pressure ◽  
Molding Pressure ◽  
Low Density ◽  
Molding Compound ◽  
Sheet Molding Compound ◽  
Insulation Performance

Low Density and Low Pressure Sheet Molding Compounds (LD-LPMC) were prepared by using magnesium oxide paste and crystalline polyester as thickening system to reduce molding pressure and Hollow Glass Microspheres (HGM) as fillers to reduce the density. The molding pressure of LD-LPMC was investigated. The effects of HGM content (0%, 3.8%, 7.6%, 11.4%, 15.2%, 19.0%) on the density, flexural strength and thermal conductivity of LD-LPMC were studied. The results showed that 2-4Mpa was the best molding pressure for the composite materials. With the increase of HGM content, the density, flexural strength and thermal conductivity of LD-LPMC decreased. The thermal conductivity increased with the increase of temperature. When the molding pressure was 3Mpa and the content of the HGM was 7.6%, the density decreased by 13.6%, the flexural strength only decreased by 23.3% and the thermal conductivity (40°C) also decreased by 11.5%, which reflected the low density, high strength and good thermal insulation performance of LD-LPMC.

Sign in / Sign up

Export Citation Format

Share Document