Accurate Simulation of the Four Modes of Post-Die Extrudate Shape Distortion

2021 ◽  
Vol 36 (1) ◽  
pp. 69-78
Author(s):  
M. Gupta
Keyword(s):  
Layer Structure ◽  
Die Design ◽  
Velocity Variation ◽  
Shape Distortion ◽  
Exit Velocity ◽  
Extrusion Die ◽  
Combined Flow ◽  
Extruded Product ◽  
Simulation Results ◽  
Extrudate Distortion

Abstract A combined flow, thermal and structural analysis is employed to simulate post-die extrudate distortion in different profile dies. All four factors which can cause extrudate distortion, namely, nonuniform exit velocity distribution, extrudate shrinkage, extrudate draw down, and deformed shape of the calibrator or sizer profile, are simulated. To analyze the effect of exit velocity variation on extrudate distortion, the parameterized geometry of a simple profile die is optimized using an extrusion die optimization software. The simulation results presented for a bi-layer profile die successfully demonstrate how gradually changing profile shape in successive calibrators/sizers can be used to simplify the die design for extrusion of complex profiles. The predicted extrudate shape and layer structure for the bi-layer die are found to accurately match with those in the extruded product.

scholarly journals Determination of an Extrusion Machine Performance Based on the Working Field of the Extruder Die

2021 ◽  
Vol 58 (3) ◽  
pp. 217-230
Author(s):  
Valeriu V. Jinescu ◽  
Mihail Juganaru ◽  
Cosmin Jinescu ◽  
Nicoleta Sporea
Keyword(s):  
Polymer Melt ◽  
Ethylene Vinyl Acetate ◽  
Heating System ◽  
Maximum Output ◽  
Economic Output ◽  
Extrusion Dies ◽  
Machine Performance ◽  
Extrusion Die ◽  
Short Service Life ◽  
Extruded Product

Some inventions along with theoretical and experimental research made it possible to increase the output of a thermally homogeneous melt provided by the screw. However, the quality of the extruded product depends on some specific features of the extrusion die and to a large extent on the rheological behavior (viscous and elastic) of the polymer melt. The mismatch between the design of the screw-cylinder subassembly and the design of the extrusion die results in products with relatively short service life. The present paper has drawn up the working field of the extruder die and adjusted it based on the limitations imposed by the screw-cylinder subassembly, namely: - the maximum output rate that ensures the required thermal homogeneity of the melt; - the maximum output at which the heating system on the barrel (and possibly the screw) ensures the extrusion temperature; - the minimum economic output corresponding to the diameter of the screw. The working field of some extrusion dies for blown films of the following polymers have been plotted: polypropylene, low density polyethylene, high density polyethylene and ethylene vinyl acetate.

scholarly journals A Practical Compressor Casing Treatment

1997 ◽  
Author(s):  
Syed Khalid
Keyword(s):  
Suction Side ◽  
Velocity Variation ◽  
Cell Orientation ◽  
Stall Margin ◽  
Exit Velocity ◽  
Casing Treatment ◽  
Multi Stage ◽  
Pressure Profiles ◽  
Inclination Angles ◽  
Side Flow

A three stage compressor test incorporating casing inserts comprised of compound angled honeycomb cells demonstrated up to 10% higher stall margin than circumferential grooves casing treatment. This is attributed to effective tip flow energization resulting from the unsteady flow induced in and out of the cells as the blade tip sweeps by the cell openings. The rationale for selecting the cell inclination angles both relative to the normal and the tangential directions is discussed. The design intent of the cell orientation is to induce a high cell exit velocity as well as to impart a degree of flow alignment to the injected jets. A first order calculation of cell exit velocity variation based on the cell pressure/volume dynamics is indicative of unsteady blowing which is theorized to effectively mix the tip suction side flow and to enhance the tip flow streamwise momentum. This theory is partially substantiated by the presented compressor test results showing improved radial total pressure profiles, stage characteristics, and stall margin. Since a few unhealthy stages of a multi-stage compressor could make it stall prone, casing treatment of those weak stages could dramatically increase stall margin with negligible impact on overall adiabatic efficiency. In addition to the aerodynamic effectiveness, the mechanical suitability of this casing treatment to multistage compressors, based on its demonstrated abradability and packageability, is discussed.

High Quality Non-Ferrous Die Castings Dependence on Die Design – A Review of the Use of Die Filling and Casting Solidification Simulation Results for Successful, Effective and Practical Die Designs

2014 ◽  
Vol 1019 ◽  
pp. 143-151
Author(s):  
Carl J. Reinhardt ◽  
Morris Murray ◽  
Isaac Bohlken
Keyword(s):  
High Pressure ◽  
Cost Effective ◽  
Die Design ◽  
Dynamics Simulation ◽  
High Quality ◽  
Design Defect ◽  
Simulation Results ◽  
Die Castings ◽  
Pressure Die Casting ◽  
The Impact

High Quality Cost Effective Die Castings rely to a large extent on successful, effective and practical die design. A review is carried out of some runner and gate designs which resulted in successful high quality castings. Some High Pressure and Gravity cast casting are evaluated. Simulation results for evaluating the impact on the flow during filling due to Runner Geometries, Gate Geometries and positions as well as venting, overflows or risers are discussed. Thermal intervention through the use of internal thermal channels are also evaluated through the use of simulation results. The paper centres on a discussion of analysis of simulation results, predicting defects which impact on some aspects of surface finish and porosity. A case study is presented showing the value of following and taking heed of lessons learnt from simulation results, to carry out die designs with reduced reliance on simulation. Index Terms: South African Foundries, High Pressure Die Casting, Computerised Fluid Dynamics Simulation, Die Design, Defect Reduction.

Numerical Simulation and Process Research for Cylindrical Drawing

2010 ◽  
Vol 20-23 ◽  
pp. 1405-1408 ◽  
Author(s):  
Wei Hua Kuang ◽  
Qun Liu
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Process Research ◽  
Die Design ◽  
Drawing Process ◽  
3D Finite Element ◽  
Simulation Results ◽  
Distribution Of Stress

Drawing process is an important technology in shaping products. In the paper, the geometric surfaces of tools and sheet were modeled by Pro/E software, and a 3D finite element model of the cylindrical drawing process was developed by DYNAFORM. Numerical simulation results showed the distribution of stress, strain and thickness. FLD showed no material was in crack area and risk crack area. The drawing process could be successfully completed in one stroke. The simulation results were helpful for the die design.

Collaborative Aluminum Profile Design to Adaptable Die Process Planning Using Neural Networks

2010 ◽  
Vol 443 ◽  
pp. 207-212 ◽  
Author(s):  
Suthep Butdee ◽  
Chaiwat Noomtong ◽  
Serge Tichkiewitch
Keyword(s):  
Neural Network ◽  
Process Planning ◽  
Collaborative Design ◽  
Die Design ◽  
Machining Process ◽  
Aluminum Extrusion ◽  
Product Data ◽  
Die Geometry ◽  
Extrusion Die ◽  
Profile Design

Aluminum extrusion die manufacturing is a critical task for productive improvement and increasing potential of competition in aluminum extrusion industry. It causes to meet the efficiency not only consistent quality but also time and production cost reduction. Die manufacturing consists first of die design and process planning in order to make a die for extruding the customer’s requirement products. The efficiency of die design and process planning are based on the knowledge and experience of die design and die manufacturer experts. This knowledge has been formulated into a computer system called the knowledge-based system. It can be reused to support a new die design and process planning. Such knowledge can be extracted directly from die geometry which is composed of die features. These features are stored in die feature library to be prepared for producing a new die manufacturing. Die geometry is defined according to the characteristics of the profile, is called product data, so we can reuse die features from the previous similar profile design cases. This paper presents the artificial neural network to assist aluminum extrusion die design and process planning based on collaborative design methodology. Product data can be shared and distributed in die design team members via computer network technology. This product data is used to support die design and process planning. Die manufacturing cases in the case library would be retrieved with searching and learning method by neural network for reusing or revising it to build a die design and process planning when a new case is similar with the previous die manufacturing cases. The results of the system are dies design and machining process.

scholarly journals A Numerical Modelling Approach for Time-Dependent Deformation of Hot Forming Tools under the Creep-Fatigue Regime

2016 ◽  
Vol 2016 ◽  
pp. 1-13
Author(s):  
B. Reggiani ◽  
L. Donati ◽  
L. Tomesani
Keyword(s):  
Plastic Deformation ◽  
Die Design ◽  
Time Dependent ◽  
Hot Forming ◽  
Small Scale ◽  
Regression Equations ◽  
Premature Failure ◽  
Extrusion Die ◽  
Temperature State ◽  
Creep Fatigue

The present study was aimed at predicting the time-dependent deformation of tools used in hot forming applications subjected to the creep-fatigue regime. An excessive accumulated plastic deformation is configured as one of the three main causes of premature failure of tools in these critical applications and it is accumulated cycle by cycle without evident marks leading to noncompliant products. With the aim of predicting this accumulated deformation, a novel procedure was developed, presented, and applied to the extrusion process as an example. A time-hardening primary creep law was used and novel regression equations for the law’s coefficients were developed to account not only for the induced stress-temperature state but also for the dwell-time value, which is determined by the selected set of process parameters and die design. The procedure was validated against experimental data both on a small-scale extrusion die at different stress, temperature, load states, and for different geometries and on an industrial extrusion die which was discarded due to the excessive plastic deformation after 64 cycles. A numerical-experimental good agreement was achieved.

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