Back-Pressure Forging Using a Servo Die Cushion

2015 ◽  
Vol 9 (2) ◽  
pp. 184-192 ◽  
Author(s):  
Kiichiro Kawamoto ◽  
◽  
Takeshi Yoneyama ◽  
Masato Okada ◽  
Keyword(s):  
Material Flow ◽  
Back Pressure ◽  
Low Back ◽  
Excellent Performance ◽  
Forming Process ◽  
Shape Accuracy ◽  
Forging Process ◽  
Forward Extrusion ◽  
High Responsiveness ◽  
Forged Parts

The application of a servo die cushion to the back-pressure forging process improves the shape accuracy of forged parts. Servo die cushions have excellent performance in precise motion control and high responsiveness to set loads. To use a servo die cushion to obtain these features, back pressure is applied to the bottom outer punch during forward extrusion-type forging. Without back pressure, material flow delay around the central counter punch corner results in an unfilled corner at the bottom outer punch. Applying back pressure to the outer punch reduces the area of the unfilled corner. However, extensive back pressure at the beginning of the forming process causes burrs at the bottom because of the clearance between the counter punch and the outer punch; variable back-pressure settings along the punch stroke effectively remove burrs while also providing a smaller unfilled area by allowing for low back pressure at the beginning of the forming process and high back pressure during the forming process. Furthermore, using the flexible slide motion of the servo press to vary the punch motion leads to even further reduction in the unfilled area.

A New Theoretical Method for Analysis the Material Flow Pattern in Forward Extrusion

2012 ◽  
Vol 622-623 ◽  
pp. 452-456
Author(s):  
Babak Saghafi ◽  
Karen Abrinia
Keyword(s):  
Conformal Mapping ◽  
Flow Pattern ◽  
Material Flow ◽  
Circular Cross Section ◽  
Physical Modelling ◽  
Model Material ◽  
Optimum Shape ◽  
Forming Process ◽  
Theoretical Formulation ◽  
Forward Extrusion

Material flow pattern in extrusion is an important part of the forming process. Understanding and formulating the material flow helps to determine the optimum shape of the die and important details of the process. In this paper, physical modelling of forward extrusion of non-symmetric L-shape section has been carried out to obtain an experimental understanding of the material flow pattern. A theoretical formulation using the conformal mapping theory has also been presented to predict the material flow pattern. The conformal mapping function was set up to translate the non-circular cross-section region of special-shaped products into unit dish. The results for the material flow pattern for the forward extrusion of L shaped profile from circular billets are presented here. In the physical modelling tests plasticine was used as the model material and different coloured layers of plasticine were used to build up the billet. Experimental and theoretical results were compared and good agreements were observed.

scholarly journals Cold Forging Effect on the Microstructure of Motorbike Shock Absorbers Fabricated by Tube Forming in a Closed Die

2021 ◽  
Vol 11 (5) ◽  
pp. 2142
Author(s):  
Trung-Kien Le ◽  
Tuan-Anh Bui
Keyword(s):  
Material Flow ◽  
Cold Forging ◽  
Technological Parameters ◽  
Forming Process ◽  
Tube Forming ◽  
Shock Absorbers ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Quality Of Products ◽  
Forming Defects

Motorbike shock absorbers made with a closed die employ a tube-forming process that is more sensitive than that of a solid billet, because the tube is usually too thin-walled to conserve material. During tube forming, defects such as folding and cracking occur due to unstable tube forming and abnormal material flow. It is therefore essential to understand the relationship between the appearance of defects and the number of forming steps to optimize technological parameters. Based on both finite element method (FEM) simulations and microstructural observations, we demonstrate the important role of the number and methodology of the forming steps on the material flow, defects, and metal fiber anisotropy of motorbike shock absorbers formed from a thin-walled tube. We find limits of the thickness and height ratios of the tube that must be held in order to avoid defects. Our study provides an important guide to workpiece and processing design that can improve the forming quality of products using tube forming.

scholarly journals Material flow control in sheet-bulk metal forming processes using blasted tool surfaces

2018 ◽  
Vol 190 ◽  
pp. 13003 ◽  
Author(s):  
Marion Merklein ◽  
Maria Löffler ◽  
Daniel Gröbel ◽  
Johannes Henneberg
Keyword(s):  
Metal Forming ◽  
Material Flow ◽  
Simultaneous Occurrence ◽  
Tribological Behaviour ◽  
Forming Process ◽  
Functional Elements ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Main Challenge ◽  
Functional Components

Highly-integrated and closely-tolerated functional components can be produced by sheet-bulk metal forming which is the application of bulk forming operations on sheet metals. These processes are characterized by a successive and/or simultaneous occurrence of different load conditions such as stress and strain states which reduce the geometrical accuracy of the functional elements. Thus, one main challenge within sheet-bulk metal forming is the identification of methods to control the material flow and thus to improve the product quality. One suitable approach is to control the material flow by local modifications of the tribological conditions. Within this study requirements regarding the needed adaption of the tribological conditions for a specific sheet-bulk metal forming process were defined by numerical investigations. The results reveal that a local increase of the friction leads to an improved die filling of the functional elements. Based on these results abrasive blasting as a method to modify the tool surface and thus influencing the tribological behaviour was investigated. For the determination of the tribological mechanism of blasted tool surfaces, the influence of different blasting media as well as blasting pressures on the surface integrity and the friction were determined. The correlations between surface properties and friction conditions were used to derive the mechanisms of blasted tool surfaces.

Influence of Element Number on Shape Accuracy in Multi-Point Stretch Forming of Air Craft

2011 ◽  
Vol 130-134 ◽  
pp. 2240-2244
Author(s):  
Jing Ling Wang ◽  
Zhong Yr Cai ◽  
Mine Zhe Li ◽  
Hui Yang
Keyword(s):  
Flexible Manufacturing ◽  
Three Dimensional ◽  
Great Influence ◽  
Stretch Forming ◽  
Forming Process ◽  
Shape Accuracy ◽  
Part Quality ◽  
Die Surface ◽  
Dimensional Shape ◽  
Element Number

Multi-point stretch forming is a flexible manufacturing technique for three-dimensional shape forming of craft skin. Its die surface is constructed by many pairs of matrices of elements whose height is controlled by computer. It uses the curved surface of elements instead of the die surface. The element numberis an important parameter because it has great influence on the part quality. This paper simulates the forming process of paraboloid part and saddle-shaped part with different number of elements and studies the influence of element number on the shape accuracy of the part .That will provides guidance for the application of multi-point stretch forming.

scholarly journals High productivity micro rotary swaging

2018 ◽  
Vol 190 ◽  
pp. 15002 ◽  
Author(s):  
Eric Moumi ◽  
Marius Herrmann ◽  
Christian Schenck ◽  
Bernd Kuhfuss
Keyword(s):  
Material Flow ◽  
Process Variations ◽  
Main Process ◽  
Forming Process ◽  
Workpiece Material ◽  
High Productivity ◽  
Rotary Swaging ◽  
Micro Parts ◽  
Intensive Investigation ◽  
Clamping Device

Rotary swaging is an incremental forming process with two main process variations plunge and infeed rotary swaging. With plunge rotary swaging, the diameter is reduced within a limited section whereas the infeed rotary swaging enables a diameter reduction over the entire workpiece length. The process is now subject to intensive investigation for manufacturing of micro parts. By increasing the process speed, failures occur particularly due to inappropriate material flow. In plunge rotary swaging, the workpiece material can flow radially into the gap between the dies and thus the workpiece quality suffers. In infeed rotary swaging the workpiece material flows against the feeding direction and can provoke bending or braking of the workpiece. Therefore, additional measures to control both the radial and the axial material flow to enable high productivity micro rotary swaging are investigated. The radial material flow during plunge rotary swaging can be controlled by elastic intermediate elements that enable an increase of productivity by factor three. A spring-loaded clamping device that enables an increase of the productivity by factor four can temporarily buffer the axial material flow in infeed rotary swaging against the feeding direction.

Semisolid Forging of Hypereutectic Al-Si Alloy for Automobile AC Compressor Components

2012 ◽  
Vol 192-193 ◽  
pp. 551-555
Author(s):  
Zhi Feng Zhang ◽  
Jun Xu ◽  
Yue Long Bai ◽  
Ya Bao Wang
Keyword(s):  
Cast Iron ◽  
High Performance ◽  
Low Cost ◽  
Nodular Cast Iron ◽  
Transportation Systems ◽  
Light Metals ◽  
Forming Process ◽  
Forging Process ◽  
Swash Plate ◽  
Near Net Shape

Semisolid forging process, characterized by short process, near-net shape, low cost, and high performance, is increasingly playing an important role in lightweighting transportation systems for light metals. In this study, semisolid forging process for hypereutectic Al-Si alloy, as a substitute for nodular cast iron, was applied in producing automobile AC compressor components. The results showed that hypereutectic Al-Si alloy swash plate thixo-forged had higher strength than nodular cast iron one by optimizing forming process parameters.

Improved Sheet Bulk Metal Forming Processes by Local Adjustment of Tribological Properties

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
H. Hetzner ◽  
J. Koch ◽  
S. Tremmel ◽  
S. Wartzack ◽  
M. Merklein
Keyword(s):  
Contact Pressure ◽  
Metal Forming ◽  
Material Flow ◽  
System Analysis ◽  
Sheet Thickness ◽  
Fe Model ◽  
Forming Process ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Functional Features

This paper is focused on a combined deep drawing and extrusion process dedicated to the new process class of sheet bulk metal forming (SBMF). Exemplified by the forming of gearings, combined sheet and bulk forming operations are applied to sheet metal in order to form local functional features through an intended and controlled change of the sheet thickness. For investigations on the form filling and the identification of significant influencing factors on the material flow, a FE simulation model has been built. The FE model is validated by the results of manufacturing experiments using DC04 with a thickness of 2.0 mm as blank material. Due to the fact that the workpiece is in extensive contact to the tool surface and that the pressure reaches locally up to 2500 MPa, the tribological conditions are a determining factor of the process. Thus, their influence is discussed in detail in this paper. In the first instance, different frictional zones having a distinct effect on the resulting material flow are identified and their effect on improved form filling is demonstrated. Subsequently, a more comprehensive methodology is developed to define tribological zones of forming tools. For this, a system analysis of the digital mock-up of the forming process is performed. Besides friction, other relevant aspects of forming tool tribology like contact pressure, sliding velocity, and surface magnification are considered. The gathered information is employed to partition the tools into tribological zones. This is done by systematically intersecting and re-merging zones identified for each of the criterion. The so-called load-scanning test allows the investigation of the friction coefficient in dependence of the contact pressure and possible loading limits of tribological pairings. It provides an appropriate tribological model test to evaluate tribological measures like coatings, surface textures and lubricants with respect to their targeted application in particular zones. The obtained results can be employed in the layout of further forming processes to reach the desired process behavior. This can be, for example, an improved form filling, less abrasive wear and adhesive damage or lower forming forces, respectively tool load for an improved durability of the die.

Low Back Pressure, High Efficiency Automotive Cabin Air Odor Filters

1996 ◽  
Author(s):  
Kishor Gadkaree ◽  
David L. Hickman ◽  
Timothy V. Johnson
Keyword(s):  
High Efficiency ◽  
Back Pressure ◽  
Low Back

SPRINGBACK EFFECT OF AUTOMOTIVE LOWER ARM COMPONENT PREPARED VIA BURRING PROCESSING

2015 ◽  
Vol 75 (8) ◽  
Author(s):  
Muhamad Sani Buang ◽  
Shahrul Azam Abdullah ◽  
Juri Saedon ◽  
Hashim Abdullah
Keyword(s):  
Sheet Metal ◽  
High Strength ◽  
Forming Process ◽  
Shape Accuracy ◽  
Automotive Components ◽  
Stamping Process ◽  
Tool Profile ◽  
Stretch Flanging ◽  
Metal Forming Process ◽  
Made In

Complex components of the sheet metal forming process need to be designed with high precision and accuracy in order to prevent defects and misalignment of the end products. One of the sheet metal cool stamping process for these complex automotive components is burring which is the forming of a flange around a hole made in a piece of sheet metal. Springback is a common defect during the burring process. The aims of this paper are to investigate the springback effect and improve shape accuracy of hole burring by inner burring process of lower arm part for automotive lower arm part. The springback defects at hole burring usually happened on the inner burring process. Experimental stretch flanging for cold stamping process of inner burring process was used to investigate the reasons of springback effect around the burred hole for a lower arm part of high strength steel (HSS) sheets SPFH590. From the two designs of burring punch dies, the result shows the values of springback effect for clearance -0.15 which have a big gap at hole burring A arm and B arm diameters, are larger than clearance -0.34 which have small gap for inner burring process of lower arm part. The experimental analysis shows that springback is proportionally related to the punch-die clearance parameter of the tool profile where the springback increase as the clearance increases. 

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