Influence of Machine Hammer Peening on the Tribology of Sheet Forming

2014 ◽  
Vol 966-967 ◽  
pp. 397-405 ◽  
Author(s):  
Matthias Oechsner ◽  
Johannes Wied ◽  
Johannes Stock
Keyword(s):  
Tool Path ◽  
Flow Behavior ◽  
Wave Theory ◽  
Surface Structures ◽  
Forming Process ◽  
Machine Hammer Peening ◽  
Metal Forming Process ◽  
Drawing Dies ◽  
Hammer Peening ◽  
Suitable Process

The recently developed machine hammer peening process is used at the die shop of the Mercedes-Benz plant in Sindelfingen in order to replace manual surface finish of deep drawing dies. The goal of the process is surface roughness reduction after milling to ensure the tribological properties, which are necessary for the sheet metal forming process. Using machine hammer peening it is also possible to create defined surface structures that may be employed to influence local friction conditions and therewith overcome current limitations of the forming process. To take advantage of the surface structuring capabilities it is necessary to understand how to create defined surface structures using machine hammer peening and how the created structures affect friction and material flow behavior. In this work an approach is presented to describe the interaction of milling and machine hammer peening parameters on the created topography by wave theory. Especially the influence of tool path parameters of milling and consecutive machine hammer peening is investigated. The results, which are calculated using wave theory, are verified by FEM simulations and real experiments. In addition, suitable process parameters for machine hammer peening are derived from the obtained results, as they are used at the Mercedes-Benz die shop today.

Wear Analysis of Tool Surfaces Structured by Machine Hammer Peening for Foil-Free Forming of Stainless Steel

2014 ◽  
Vol 1018 ◽  
pp. 317-324 ◽  
Author(s):  
Fritz Klocke ◽  
Daniel Trauth ◽  
Michael Terhorst ◽  
Patrick Mattfeld
Keyword(s):  
Stainless Steel ◽  
Wear Resistance ◽  
Contact Area ◽  
Deep Drawing ◽  
Surface Structures ◽  
Main Concern ◽  
Forming Process ◽  
Machine Hammer Peening ◽  
Strip Drawing ◽  
Hammer Peening

Increasing demands concerning the performance of tribological systems for metal forming due to ecological restrictions or technologically increased process loads require the development of innovative tribological systems, especially in forming of stainless steel. It could be shown in preliminary work that surface structures on deep drawing tools manufactured by the incremental forming process machine hammer peening have the potential to reduce friction in strip drawing test by about 58 % in comparison with a ground reference surface. This is explained by the effect of lubricant pockets and a reduced true contact area in the interacting zone. However, due to the effect of a reduced contact area, the wear resistance of these surface structures is of main concern for the effectiveness of their application in deep drawing. Therefore, in this work strip drawing tests are performed over a minimum of 500 repetitions for the evaluation of friction characteristics. Additionally, the coating of the surface structures is investigated to improve the wear resistance of the structures.

2D-CFD Analysis of the Fluid Pressure and Velocity Distribution of Experimentally Machine Hammer Peened Surface Structures in Hydrodynamic Applications

2015 ◽  
Vol 794 ◽  
pp. 174-181
Author(s):  
Daniel Trauth ◽  
Michael Terhorst ◽  
Patrick Mattfeld ◽  
Fritz Klocke
Keyword(s):  
Velocity Distribution ◽  
Deep Drawing ◽  
Fluid Dynamic ◽  
Fluid Pressure ◽  
Surface Structures ◽  
Surface Finishing ◽  
Forming Process ◽  
Machine Hammer Peening ◽  
Hydrodynamic Effects ◽  
Hammer Peening

Machine hammer peening is an incremental forming process for high frequency surface finishing of technical components. Recently, machine hammer peening has attracted automotive industry’s attention for the surface finishing and structuring of deep drawing tools. Deep drawing tools surface structured by machine hammer peening are characterized by beneficial friction and wear characteristics in lubricated sliding contacts. However, the physics of hydrodynamic effects in machine hammer peened structures is yet insufficiently researched. Therefore, this work investigates the hydrodynamic effects in surface structures generated by machine hammer peening using a two-dimensional computational fluid dynamic analysis. The effects of structure geometry, structure arrangement and selected sliding parameters on the hydrodynamic fluid pressure and velocity distribution within the structures are analysed. It was observed, that the sliding direction and the structure arrangement have a significant influence on the hydrodynamic fluid pressure maximum.

A Study on Incremental Forming of Vertical Wall Square Box with Small Radius Corner

2010 ◽  
Vol 139-141 ◽  
pp. 1510-1513
Author(s):  
Liu Ru Zhou
Keyword(s):  
Tool Path ◽  
Vertical Wall ◽  
Small Radius ◽  
Forming Process ◽  
Corner Radius ◽  
Single Process ◽  
Incremental Sheet Metal Forming ◽  
Metal Forming Process ◽  
Sine Law ◽  
Square Box

According to sine law, a vertical wall square box can’t be formed by NC incremental sheet metal forming process in a single process, rather, it must be formed in multi processes. A vertical wall square box can be considered to consist of corners and straight sides. Straight sides and corners affect each other and the effect is different in various square boxes. The effect depends on the ratio r/B of the corner radius r and straight side width B. The smaller r/B, the larger the effect of straight side on corner is. In this case, the deformation in the straight sides isn’t even, and the metal of the corner is compressed and gradually piled up. With the increase of r/B, the deformation becomes more uniform. The tool path with gradually reduced corner radius is adopted to overcome this question. A vertical wall square box with small corner radius is successfully formed.

scholarly journals On the Influence of the Tool Path and Intrusion Depth on the Geometrical Accuracy in Incremental Sheet Forming

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 661
Author(s):  
Roman Ulrich Christopher Schmitz ◽  
Thomas Bremen ◽  
David Benjamin Bailly ◽  
Gerhard Kurt Peter Hirt
Keyword(s):  
Sheet Metal ◽  
Tool Path ◽  
Sheet Material ◽  
Sheet Forming ◽  
Incremental Sheet Forming ◽  
Forming Process ◽  
Geometrical Accuracy ◽  
Metal Forming Process ◽  
Short Time ◽  
Intrusion Depth

Incremental sheet forming (ISF) is a flexible sheet metal forming process to realize products within short time from design to the first produced part. Although fundamental research on ISF has been carried out around the world, ISF still misses commonly required tolerances for industrial application. In this study, the influences of tool path as well as intrusion depth of the forming tool into the sheet material on the geometrical accuracy were investigated. In the conducted experiments, both flat and stretch-formed sheet metal blanks with different tool paths and intrusion depths were examined. Experimental and numerical investigations showed that changes in the range of a tenth millimeter of the intrusion depth with a consistent tool path lead to different resulting part geometries. A better understanding of the sensitive influence of the tool path and the intrusion depth on the resulting geometry might lead to more accurate parts in the future.

Comparison between SPIF with Robot and CNC Machine

2011 ◽  
Vol 473 ◽  
pp. 929-936 ◽  
Author(s):  
Aldo Attanasio ◽  
Elisabetta Ceretti ◽  
Claudio Giardini ◽  
Silvio Antonioni
Keyword(s):  
Degrees Of Freedom ◽  
Tool Path ◽  
Sheet Material ◽  
Sheet Thickness ◽  
Cnc Machine ◽  
Forming Process ◽  
Advantages And Disadvantages ◽  
Shape Errors ◽  
Metal Forming Process ◽  
Sheet Formability

This paper deals with Incremental Sheet Forming (ISF) a sheet metal forming process that knew a wide development in the last years. A lot of experimental and simulative researches have been conducted in this field with different aims: to study the sheet formability and part feasibility; to define models able to forecast the final sheet thickness; to understand how the sheet deforms and how formability limits can be defined. Another very important issue is related with the tool path optimization. In fact, the process is characterized by high springback which causes dimensional defects. When IF is performed by a robot, the capabilities of the technology is improved in terms of obtainable shapes (it is possible to use the 6 degrees of freedom of the robot), but the shape errors seem to be higher due to the lower robot stiffness in comparison with CNC machine. In this work the comparison between two different ISF configurations, tool mounted on a CNC machine or tool mounted on a robot, is reported. A suitable geometry was investigated working different sheet material types and sheet thicknesses. The results in terms of geometrical accuracy and sheet deformation have been analyzed in order to define advantages and disadvantages of these two techniques. An analysis on the process forces has been carried out too.

Experimental Tests to Study Feasibility and Formability in Incremental Forming Process

2009 ◽  
Vol 410-411 ◽  
pp. 391-400 ◽  
Author(s):  
Aldo Attanasio ◽  
Elisabetta Ceretti ◽  
Antonio Fiorentino ◽  
Luca Mazzoni ◽  
Claudio Giardini
Keyword(s):  
Tool Path ◽  
Incremental Forming ◽  
Single Point ◽  
Sheet Thickness ◽  
Experimental Tests ◽  
Final Part ◽  
Cnc Machine ◽  
Forming Process ◽  
Metal Forming Process ◽  
Sheet Formability

This paper deals with Incremental Sheet Forming (ISF), a sheet metal forming process, that knew a wide development in the last years. It consists of a simple hemispherical tool that, moving along a defined path by means of either a CNC machine or a robot or a self designed device, locally deforms a metal sheet. A lot of experimental and simulative researches have been conducted in this field with different aims: to study the sheet formability and part feasibility as a function of the process parameters; to define models able to forecast the final sheet thickness as a function of the drawing angle and tool path strategy; to understand how the sheet deforms and how formability limits can be defined. Nowadays, a lot of these topics are still open. In this paper, the results obtained from an experimental campaign performed to study sheet formability and final part feasibility are reported. The ISF tests were conducted deforming FeP04 deep drawing steel sheet 0.8 mm thick and analyzing the influence of the tool path strategy and of the adopted ISF technique (Single Point Incremental Forming Vs. Two Points Incremental Forming). The part feasibility and formability were evaluated considering final sheet thickness, geometrical errors of the final part, maximum wall angle and depth at which the sheet breaks. Moreover, process forces measurements were carried out by means of a specific device developed by the Authors, allowing to obtain important information about the load acting on the deforming device and necessary for deforming sheet.

Incremental Forming Process for the Accomplishment of Automotive Details

2007 ◽  
Vol 344 ◽  
pp. 559-566 ◽  
Author(s):  
A. Governale ◽  
A. Lo Franco ◽  
A. Panzeca ◽  
Livan Fratini ◽  
Fabrizio Micari
Keyword(s):  
Automotive Industry ◽  
Tool Path ◽  
Incremental Forming ◽  
Single Point ◽  
Innovation Process ◽  
Forming Process ◽  
Metal Forming Process ◽  
New Methodologies ◽  
Auto Body ◽  
Aluminium Sheets

In the last decades the scenario of the industrial production is remarkably changed, since new market requirements have to be faced by the industries. The market, actually, more and more, asks for vary models and niches product. The necessity to intercept dynamically and to satisfy the demands for the market, driver of the innovation process, involves the necessity to reduce the Timeto- market introducing to new methodologies of engineering, like the 3D-prototyping, for the qualitative and structural analysis of the final component. For these reasons, at the beginning of the nineties, a new philosophy of sheet metal forming process begins to assert on the industrial scene, whose basic logic is to obtain the shape wished through the progressive action of a tool of simple shape. In this job the application of the simplest process of incremental process on an industrial detail - famous in international field like SPIF (Single Point Incremental Forming) - will be described. The process is intrinsically flexible, and therefore is adapted to the rapid prototyping. The cases are still least, notice in the scientific literature, in which the details of industrial interest have been developed by Incremental Forming process; for this reason, the subject of this job is focused on the evaluation of the possibility to obtain real components of the automotive industry through the SPIF process. The job has been carried out in the R&D laboratory of "Fontana Pietro S.p.A.”, leader in the field of die manufacturing and stamping of component of the automotive industry. In particular, two parts of automotive auto body of aluminium sheets have been considered. It has been lead an analysis of technological and process feasibility, optimizing tool path considering experiences to obtain a product/process for the production of auto body prototypes.

Deflection Compensations for Tool Path to Enhance Accuracy During Double-Sided Incremental Forming

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Lingam Rakesh ◽  
Srivastava Amit ◽  
N. V. Reddy
Keyword(s):  
Deformation Zone ◽  
Tool Path ◽  
Incremental Forming ◽  
Single Point ◽  
Three Dimensional ◽  
Geometric Accuracy ◽  
Forming Process ◽  
Sheet Plane ◽  
Support Tool ◽  
Metal Forming Process

Incremental sheet forming (ISF) is a flexible sheet metal forming process that enables forming of complex three-dimensional components by successive local deformations without using component-specific tooling. ISF is also regarded as a die-less manufacturing process in the absence of part-specific die. Geometric accuracy of formed components is inferior to that of their conventional counterparts. In single-point incremental forming (SPIF), the simplest variant of ISF, bending near component opening region is unavoidable due to lack of support. The bending in the component opening region can be reduced to a larger extent by another variant of ISF, namely, double-sided incremental forming (DSIF) in which a moving tool is used to support the sheet locally at the deformation zone. However, the overall geometry of formed components still has unacceptable deviation from the desired geometry. Experimental observation and literature indicate that the supporting tool loses contact with the sheet after forming certain depth. This work demonstrates a methodology to enhance geometric accuracy of formed components by compensating for tool and sheet deflections due to forming forces. Forming forces necessary to predict compensations are obtained using force equilibrium method along with thickness calculation methodology developed using overlap of deformation zone that occurs during forming (instead of using sine law). A number of examples are presented to show that the proposed methodology works for a variety of geometries (axisymmetric, varying wall angle, free-forms, features above and below initial sheet plane, and multiple features). Results indicate that there is significant improvement in accuracy of the components produced using compensated tool paths using DSIF, and support tool maintains contact with sheet throughout the forming process.

scholarly journals Surface Integrity of AISI 52100 Bearing Steel after Robot-Based Machine Hammer Peening

2020 ◽  
Vol 4 (2) ◽  
pp. 61
Author(s):  
Robby Mannens ◽  
Lars Uhlmann ◽  
Felix Lambers ◽  
Andreas Feuerhack ◽  
Thomas Bergs
Keyword(s):  
Surface Layer ◽  
Surface Integrity ◽  
Bearing Steel ◽  
Forming Process ◽  
Premature Failure ◽  
Machine Hammer Peening ◽  
Aisi 52100 ◽  
Aisi 52100 Steel ◽  
Hardness Increase ◽  
Hammer Peening

AISI 52100 steel is often used as material for highly loaded rolling bearings in machine tools. An improved surface integrity, which can be achieved by means of mechanical surface layer finishing, can avoid premature failure. One of these finishing processes is machine hammer peening (MHP) which is a high-frequency incremental forming process and mostly used on machining centers. However, the influence of robot-guided MHP processing on the surface integrity of AISI 52100 steel is still unknown. Therefore, the objective of this work is to investigate experimentally the robot-based influences during MHP processing and the resulting surface integrity of unhardened AISI 52100 steel. The results show that the axial and lateral deviations of the robot due to process vibrations are in the lower µm range, thus enabling stable and reproducible MHP processing. By selecting suitable MHP process parameters and thus defined contact energies, even ground surfaces can be further smoothed and a hardness increase of 75% in the energy range considered can be achieved. In addition, compressive residual stress maxima of 950 MPa below the surface and a grain size reduction to a surface layer depth of 150 µm can be realized.

Robot-Based Incremental Sheet Metal Forming – Increasing the Part Accuracy in an Automated, Industrial Forming Cell

2009 ◽  
Vol 410-411 ◽  
pp. 159-166 ◽  
Author(s):  
Horst Meier ◽  
B. Buff ◽  
V. Smukala
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Tool Path ◽  
Cost Effective ◽  
Programming System ◽  
Forming Process ◽  
Incremental Sheet Metal Forming ◽  
Metal Forming Process ◽  
Formed Part

This paper describes new developments in incremental, robot-based sheet metal forming (Roboforming). Roboforming is a dieless sheet metal forming process which ensures cost-effective manufacturing of prototype parts and small batches. An approach for increasing the part accuracy in Roboforming is presented. It is developed in a cooperative project funded by the German Federal Ministry of Education and Research called Roboforming. The project concentrates on the development of an industrial applicable system design. The use of standard components allows a modular and scalable set-up. A servo loop, consisting of sensors and a programming system, represents the basis of this design and shall guarantee higher part accuracies by measuring the deviations between a formed part and its target geometry. The deviations are used to derive corrected tool paths. The correction is performed by an adjustment vector for every point on the tool path. The theory for this strategy and first results are presented in this paper.

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