scholarly journals RANCANG BANGUN MOLD UNTUK PROSES TERMOFORMING PROSTHETIC BELOW KNEE (B/K)

2017 ◽  
Vol 18 (2) ◽  
Author(s):  
Bambang Waluyo Febriantoko ◽  
Aris Aryanto ◽  
Tri Widodo Besar Riyadi
Keyword(s):  
Plastic Material ◽  
Forming Process ◽  
Temperature Variations ◽  
Plastic Shrinkage ◽  
Pressing Process ◽  
Plastic Forming ◽  
Thermoforming Process ◽  
Good Expansion

ABSTRAK Industri semakin berkembang, kebutuhan terhadap plastik pun semakin bertambah. Akan tetapi, dalam aplikasi proses pembentukan plastik sering mengalami kendala. Salah satunya adalah penyusutan. Penyusutan sering terjadi pada proses pembentukan plastik, terutama pembentukan dengan sistem mechanical thermoforming. Sehingga perlu dianalisis hal-hal yang menyebabkan penyusutan pada produk yang dihasilkan. Beberapa hal yang diidentifikasi mempengaruhi terjadinya penyusutan adalah bentuk mold, temperatur, dan jenis plastik yang digunakan.Metode penelitian yang digunakan adalah membuat alat uji mechanical thermoforming dan  membuat  mold  yang  akan  digunakan  untuk  menganalisis  penyusutan.  Mold yang digunakan ada 2 macam, yaitu mold telapak kaki atas dan mold telapak kaki bawah. Selain variasi pada mold, analisis juga ditujukan pada temperatur plastik polypropylene (PP) dan plastik PVC yang akan diproses. Variasi temperatur yaitu:1000C,  1200C,  dan  140oC.  Sedangkan  jenis  plastik  yang  diujikan  adalah  plastikpolypropylene (PP) dan plastik PVC.Dari data hasil pengujian dan pembahasan pada proses mechanical thermoforming untuk plastik polypropylene (PP) dengan ketebalan 1,0 mm tidak dapat dianalisis persentase penyusutan yang terjadi karena sifat viskos pada plastik rendah. Pada plastik jenis PP ini meskipun membentuk pola, tetapi tidak sempurna. Bahan plastik PP setelah proses penekanan dengan temperatur 100ºC-120ºC plastik tidak mengalami pemuaian yang cukup baik, karena plastik masih bersifat elastik. Pada temperatur140ºC plastik mengalami pemuaian, tetapi saat proses penekanan plastik mengalami bentuk pola yang tidak sempurna, karena temperatur terlalu tinggi. Sedangkan pada plastik PVC didapatkan hasil bahwa pada mold telapak kaki atas dengan ketinggian2 cm dan tebal plastik 1,0 mm menghasilkan persentase penyusutan rata-rata 7,85% dengan temperatur 100ºC, 9,80% dengan temperatur 120ºC dan 12,11% dengan temperatur 140ºC. Pada mold telapak kaki bawah dengan ketinggian 2 cm dan tebal plastik 1,0 mm menghasilkan persentase penyusutan rata-rata 10,01% dengan temperatur 100ºC, 10,96% dengan temperatur 120ºC dan 12,08% dengan temperatur140ºC. Kata Kunci: Mechanical thermoforming, penyusutan plastik, mold ABSTRACT The growing of industry has the effect to the increase of plastic need.  However, the application of plastic forming process often experiences constraints. One of them is depreciation. Depreciation often occurs in the plastic forming process, especially forming with mechanical thermoforming system. So it is necessary to analyze the things that cause shrinkage on the product. Some of the things that are identified to influence the shrinkage are the molds, temperatures and types of used plastics.The used method is to make mechanical thermoforming test and make mold which will be used to analyze depreciation. There are 2 kinds of molds, namely upper foot sole mold and bottom foot sole mold. In addition to the variations of the mold, the analysis is also aimed at the temperature of polypropylene plastic (PP) and PVC plastic which will be processed. The temperature variations are 1000C, 1200C and 140oC and the types of plastics that are tested is polypropylene plastic (PP) and PVC plastic.The results show that on mechanical thermoforming process for polypropylene (PP) plastic with 1.0 mm thickness, the percentage of shrinkage can not be analyzed because of the low viscous nature of plastic. PP type plastic can form a pattern, but not perfect. PP plastic material does not experience a good expansion after pressing process with100ºC-120ºC plastic temperature. This is because the plastic is still elastic. At 140ºC, the plastic undergoes expansion, but when the plastic pressing process, it undergoes an imperfect pattern. The reason is the temperature is too high. Meanwhile for the PVC plastic, it was found that in the upper foot sole mold with height of 2 cm and 1.0 mm plastic thickness, the percentages of shrinkage average are 7.85% with temperature100ºC, 9.80% with temperature 120ºC and 12.11% with temperature of 140ºC. In the bottom foot sole mold with 2 cm height and 1.0 mm plastic thickness, the percentages of shrinkage average are 10.01% with temperature 100ºC, 10.96% with temperature120ºC and 12.08% with temperature 140ºC. Keywords: Mechanical thermoforming, plastic shrinkage, mold

scholarly journals Plastic forming processes of transverse non-homogeneous composite metallic sheets

2021 ◽  
Vol 11 (1) ◽  
pp. 294-302
Author(s):  
Gal Davidi
Keyword(s):  
Inner Core ◽  
Plastic Material ◽  
Radial Solution ◽  
Algebraic Differential Equation ◽  
Forming Process ◽  
Perfectly Plastic ◽  
Plastic Forming ◽  
Validity Limit ◽  
Significant Achievement

Abstract In this work an analysis of the radial stress and velocity fields is performed according to the J 2 flow theory for a rigid/perfectly plastic material. The flow field is used to simulate the forming processes of sheets. The significant achievement of this paper is the generalization of the work by Nadai & Hill for homogenous material in the sense of its yield stress, to a material with general transverse non-homogeneity. In Addition, a special un-coupled form of the system of equations is obtained where the task of solving it reduces to the solution of a single non-linear algebraic differential equation for the shear stress. A semi-analytical solution is attained solving numerically this equation and the rest of the stresses term together with the velocity field is calculated analytically. As a case study a tri-layered symmetrical sheet is chosen for two configurations: soft inner core and hard coating, hard inner core and soft coating. The main practical outcome of this work is the derivation of the validity limit for radial solution by mapping the “state space” that encompasses all possible configurations of the forming process. This configuration mapping defines the “safe” range of configurations parameters in which flawless processes can be achieved. Several aspects are researched: the ratio of material's properties of two adjacent layers, the location of layers interface and friction coefficient with the walls of the dies.

Spatial free plastic forming of slender parts—numerical approaches for strain-hardening material

2004 ◽  
Vol 218 (6) ◽  
pp. 641-650 ◽  
Author(s):  
M Thalmair ◽  
H Lippmann
Keyword(s):  
Strain Hardening ◽  
Metal Forming ◽  
Plastic Material ◽  
Forming Process ◽  
Hardening Material ◽  
Final Shape ◽  
Metal Forming Process ◽  
Plastic Forming ◽  
Elastic Plastic Material ◽  
Numerical Approaches

A new metal forming process is described in which a slender part may be brought to a prescribed final shape by means of an appropriate, pre-calculated motion of its free ends only. Corresponding calculation schemes are presented for elastic/plastic material with strain hardening, and these are illustrated by practical examples.

A Study on the Flow Behavior of 42CrMo Steel under Hot Compression by Thermal Physical Simulations

2010 ◽  
Vol 108-111 ◽  
pp. 494-499
Author(s):  
Ying Tong ◽  
Guo Zheng Quan ◽  
Gang Luo ◽  
Jie Zhou
Keyword(s):  
Strain Rate ◽  
Flow Behavior ◽  
Rate Sensitivity ◽  
Strain Hardening Exponent ◽  
Forming Process ◽  
Material Parameters ◽  
Basic Model ◽  
42Crmo Steel ◽  
Plastic Forming ◽  
Physical Simulations

This work was focused on the compressive deformation behavior of 42CrMo steel at temperatures from 1123K to 1348K and strain rates from 0.01s-1 to 10s-1 on a Gleeble-1500 thermo-simulation machine. The true stress-strain curves tested exhibit peak stresses at small strains, after them the flow stresses decrease monotonically until high strains, showing a dynamic flow softening. And the stress level decreases with increasing deformation temperature and decreasing strain rate. The values of strain hardening exponent n, and the strain rate sensitivity exponent m were calculated the method of multiple linear regression, the results show that the two material parameters are not constants, but changes with temperature and strain rate. Then the two variable material parameters were introduced into Fields-Backofen equation amended. Thus the constitutive mechanical discription of 42CrMo steel which can accurately describe the relationships among flow stress, temperature, strain rate, strain offers the basic model for plastic forming process simulation.

Coupled Thermo-Mechanical FEA of Three-Roll Cross Rolling Process for Rings with Small-Hole and Deep Groove

2012 ◽  
Vol 560-561 ◽  
pp. 846-852 ◽  
Author(s):  
Qi Ma ◽  
Lin Hua ◽  
Dong Sheng Qian
Keyword(s):  
Rolling Process ◽  
Small Hole ◽  
Fe Model ◽  
Forming Process ◽  
Software Environment ◽  
Cross Rolling ◽  
Design And Optimization ◽  
Forming Technology ◽  
Deep Groove ◽  
Plastic Forming

Ring parts with small-hole and deep groove such as duplicate gear and double-side flange, are widely used in various engineering machineries. Three-roll cross rolling (TRCR) is a new advanced plastic forming technology for the processing of rings with small-hole and deep groove. In this paper, a 3D coupled thermo-mechanical FE model for TRCR of ring with small-hole and deep groove is established under ABAQUS software environment. By simulation and analysis, the evolution and distribution laws of strain and temperature in the forming process are revealed, and the effects of the key process parameters on the deformation uniformity are explored. The results provide valuable guideline for the technological parameter design and optimization.

Study of the Strain Rate Effect on Cold-Reduced Carbon Steel and Aluminium Alloy with Numerical Simulations

2006 ◽  
Vol 532-533 ◽  
pp. 973-976
Author(s):  
Lin Wang ◽  
Tai Chiu Lee ◽  
Luen Chow Chan
Keyword(s):  
Carbon Steel ◽  
Strain Rate ◽  
Strain Path ◽  
Plastic Material ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Forming Process ◽  
Risk Area ◽  
Sensitive Material ◽  
Simulation Results

In this paper, the effect of strain rate has been considered in the simulation of forming process with a simple form combined into the material law. Quite a few researchers have proposed various hardening laws and strain rate functions to describe the material tensile curve. In this study, the strain rate model Cowper-Symonds is used with anisotropic elasto-plastic material law in the simulation process. The strain path evolution of certain elements, when the strain rate is considered and not, is compared. Two sheet materials, Cold-reduced Carbon Steel (SPCC) JIS G3141 and Aluminum alloy 6112 are used in this study. Two yield criteria, Hill 48 and Hill 90, are applied respectively to improve the accuracy of simulation result. They show different performance when strain rate effect is considered. Strain path of the elements in the fracture risk area of SPCC (JIS G3141) varies much when the strain rate material law is used. There is only little difference of the strain distribution of Al 6112 when the strain rate effect is included and excluded in the material law. The simulation results of material SPCC under two conditions indicate that the strain rate should be considered if the material is the rate-sensitive material, which provides more accurate simulation results.

scholarly journals Simulation of plastic forming process of shells with minimal thickness fluctuations

2017 ◽  
Vol 201 ◽  
pp. 489-494
Author(s):  
E.G. Demyanenko ◽  
I.P. Popov ◽  
A.N. Epifanov
Keyword(s):  
Forming Process ◽  
Minimal Thickness ◽  
Plastic Forming

Process Optimization for Suction Plastic Forming of In-Mold Decoration Plastic Sheet with CAE

2010 ◽  
Vol 102-104 ◽  
pp. 74-78
Author(s):  
Bin Gao ◽  
Xiu Rong Nan ◽  
Bai Zhong Wu
Keyword(s):  
Process Optimization ◽  
Thin Shell ◽  
Optimization Methods ◽  
Analysis Software ◽  
Optimization Scheme ◽  
Forming Process ◽  
Element Analysis ◽  
Plastic Sheet ◽  
Mesh Model ◽  
Plastic Forming

The suction plastic forming process for in-mold decoration plastic sheet has been the best process for thin-shell plastic exterior decoration parts. But the suction plastic forming products still suffers from the uneven thickness. Based on the general finite element analysis software POLYFLOW for viscoelastic fluid, a set of optimization methods for suction plastic forming process of in-mold decoration plastic sheet is introduced in this paper to reduce the uneven level of thickness. These methods include establishing process optimization scheme, building mesh model, selecting the material constitutive model and determining its parameters, imposing boundary conditions and blowing pressure, and applying the mold movement. Finally, the optimized suction plastic forming process is used to produce the in-mold decoration plastic rear bumper sample of an automobile, and the results show that optimized process is effective and applicable.

Theoretical Analysis of Laser Shock Bulging Forming

2012 ◽  
Vol 472-475 ◽  
pp. 2480-2483 ◽  
Author(s):  
Guo Fang Zhang ◽  
Zhong Ji ◽  
Jing Liu ◽  
Chao Zheng ◽  
Jian Hua Zhang
Keyword(s):  
High Pressure ◽  
Theoretical Analysis ◽  
Analytical Model ◽  
Pulse Energy ◽  
Shock Pressure ◽  
Laser Shock ◽  
Plastic Response ◽  
Forming Process ◽  
Laser Shock Forming ◽  
Plastic Forming

Laser shock forming (LSF) is a novel plastic forming process which utilizes high-pressure plasma to deform thin metals to 3D configurations. The plastic response of a circular plate in laser shock bulging forming was theoretically studied. A simplified shock pressure model was established and then an analytical model was proposed to calculate the deflection. The results show that the deflection increases with increasing pulse energy and the deformation profiles calculated by the analytical model agree well with those of experiment.

Simulation-Based Tracking of UOE Pipe Yield Strength Considering Various Thickness-to-Diameter Ratios

2018 ◽  
Author(s):  
Jiwoon Yi ◽  
Soo-Chang Kang ◽  
Hyun-Moo Koh ◽  
Jinkyo F. Choo
Keyword(s):  
Yield Strength ◽  
Bauschinger Effect ◽  
Steel Plate ◽  
Tensile Yield Strength ◽  
Forming Process ◽  
Factors Influencing ◽  
Simulation Based ◽  
Plastic Forming ◽  
Final Yield ◽  
Flattening Process

The plastic forming processes involved in the production of UOE pipes alter significantly the yield strength of the original steel plate. Numerous studies indicated that the work hardening and Bauschinger effect are the main factors influencing the alteration of the yield strength. Moreover, apart from the forming process itself, the flattening executed on strips sampled from the formed pipe appears to have also nonnegligible effect on the final yield strength that is used as quality index of the formed pipe. Therefore, this study tracks the yield strength of UOE pipe made of API-X70 steel with various thickness-to-diameter ratios by FE-simulation of the forming and flattening processes so as to identify the factors influencing the yield strength of the UOE pipe. The results show that the flattening process constitutes a critical phase in which steel experiences large loss of its tensile yield strength.

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