Corner Shaping by Barrel Finishing

2006 ◽  
Author(s):  
A. Boschetto ◽  
A. Ruggiero ◽  
F. Veniali
Keyword(s):  
Tool Path ◽  
Experimental Tests ◽  
Mechanical Action ◽  
Fitting Procedure ◽  
Electro Discharge Machining ◽  
Corner Radius ◽  
Component Design ◽  
Root Relation ◽  
Complicated Part ◽  
Barrel Finishing

Corner shaping is a necessary operation in manufacturing of most mechanical components. Edge radiusing is the principal way to reduce stress concentration in components like gear, crank shaft, ball bearing, to permit assembly and disassembly of parts, to avoid local damage and to reduce the possibility of hurting the operators. Often precise values of corner radius are specified in component design. Deterministic operations such as chipping, plastic deformation and non traditional ones such as electro discharge machining, abrasive jet deburring are well established technology. Yet, sometimes, it results not economic or even impossible to perform these operations due to the complicated part geometry, difficulty in part clamping and tool path, large number of parts to be produced. Barrel finishing is technique able to improve the roughness of parts of complicated shape by means of a soft mechanical action over the surface performed by abrasive media. The main features of this technology is that the parts do not need to be fixed. Radiusing is, in turn, a potential application area for barrel finishing which has been investigated in this paper. Experimental tests were conducted on finished specimens with sharp corners in order to achieve information about corner radius evolution as a function of the time for different set parameters. The radius values have been assessed by analyzing the acquired profiles with a proprietary fitting procedure. It has been found a square root relation between radius and working time and, by assessing the influence of single parameter, a radiusing model has been proposed.

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.

Sheet Hemming with Rolling Tools: Analysis and Optimization of the Part Quality

2007 ◽  
Vol 344 ◽  
pp. 357-364 ◽  
Author(s):  
Elisabetta Ceretti ◽  
Aldo Attanasio ◽  
Antonio Fiorentino ◽  
Claudio Giardini
Keyword(s):  
Tool Path ◽  
Outer Part ◽  
Experimental Tests ◽  
Process Time ◽  
Cnc Machine ◽  
Whole Process ◽  
Cad Cam ◽  
In Series ◽  
Aluminium Sheets ◽  
Set Up

The present paper is the continuation of a research conducted on hemming operations by using rolling tools. Sheet hemming is a joining operation widely used in automotive industry when it is necessary to join two sheet parts (such as the engine hood or the door panels with their internal frame) by plastic deformation of the edge of the outer part. The whole process is characterised by a 90° sheet flanging, a pre-hemming (up to approximately 135°) and the final hemming where the outer sheet edge is bended up to 180° clamping the inner sheet. Hemming processes are normally performed using rigid dies in series production and manually in pre-series and small batch production, due to the high cost of the dies. Nowadays, rollers moved by robots are becoming an interesting alternative to the manual operations especially when flexible productions are required. Even if the process time is higher, this solution can help in minimizing set-up times and costs. The required equipments are a support and a blocking system for the sheets together with the rollers mounted on a CNC machine or on a robot. The production flexibility is guaranteed by changing the 3D tool path using a CAD/CAM system. Authors are dealing with this technique having conducted many experiments studying the influence of the hemming process parameters such as flange geometry (edge height, fillet radius), distance of the inner panel from the flange, tool path sequence, along straight paths on steel sheets. The goal of the present research is to study the material behaviour and the produced parts quality when working on aluminium sheets. In particular, both experimental tests and simulations will be carried out in order to optimize the process.

Numerical Interpretation of Bond Between Steel and Concrete in Presence of Corrosion and Cyclic Action

2009 ◽  
Vol 417-418 ◽  
pp. 349-352 ◽  
Author(s):  
Luca Giordano ◽  
Giuseppe Mancini ◽  
Francesco Tondolo
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Stress Transfer ◽  
Experimental Tests ◽  
Radial Pressure ◽  
Mechanical Action ◽  
Concrete Cover ◽  
Reinforcing Bars ◽  
Cyclic Action ◽  
Bond Slip

Bond between steel and concrete in reinforced concrete structures plays a fundamental role. The stress transfer mechanism depends on the condition of the contact surface between the two materials, the mechanical characteristics of concrete near the rebar and on the available level of confinement. Corrosion of reinforcing bars in concrete structures modifies those three factors. Because of corrosion, on the rebar surface a granular oxide layer is present and with its expansion it generates a significant radial pressure; consequently tensile stresses grow till cracking of the concrete cover with a subsequent reduction of the confinement effect. Moreover the presence of a mechanical action modifies the resisting mechanism producing an increasing damage. In this study, a model is presented for the numerical simulation of experimental tests on r.c. ties subjected to mechanical action; furthermore some considerations on reinforced concrete ties subjected also to corrosion effect are reported. From those analyses it is possible to estimate a modified bond-slip law between the reinforcing bars and the concrete, in order to take into account the level of damage.

scholarly journals Experimental Analysis of Single Point Incremental Forming of Truncated Cones in DC04 Steel Sheet

2020 ◽  
Vol 20 (4) ◽  
pp. 5-15
Author(s):  
B. Krasowski ◽  
A. Kubit ◽  
T. Trzepieciński ◽  
J. Slota
Keyword(s):  
Tool Path ◽  
Crack Formation ◽  
Incremental Forming ◽  
Single Point ◽  
Slope Angle ◽  
Frictional Resistance ◽  
Experimental Tests ◽  
Test Material ◽  
Synthetic Lubricant ◽  
Steel Sheets

AbstractExperimental tests to form truncated cones were carried out on a 3-axis milling machine. 0.8-mm thick low-alloy DC04 steel sheets were used as test material. The profile tool-path trajectory was generated using the EDGECAM software. The slope angle and diameter of the base of the conical shaped drawpieces were 70°-72° and 65 mm, respectively. The drawpiece heights were up to 75 mm. The full synthetic lubricant 75W85 was used to reduce the frictional resistance. The effect of selected incremental forming parameters on the formability of the DC04 sheet and the susceptibility to crack formation have been analysed and discussed. It was found that the surface roughness of the workpiece is strongly influenced by step depth. By controlling the feed rate, it is possible to prevent failure of the material.

Mass Finishing of Parts Produced by Direct Metal Laser Sintering

Volume 3 ◽  
2004 ◽  
Author(s):  
A. Boschetto ◽  
F. Veniali ◽  
F. Miani
Keyword(s):  
Surface Roughness ◽  
Industrial Process ◽  
Mechanical Action ◽  
Laser Sintering ◽  
Main Process ◽  
Direct Metal Laser Sintering ◽  
Complicated Shape ◽  
Mass Finishing ◽  
Barrel Finishing ◽  
Established Technique

This paper presents some practical considerations on finishing of parts made by direct metal laser sintering (DMLS). The main process capabilities limitations of this promising rapid tooling technique are in fact in the surface roughness of the produced parts. This fact hinders the introduction of DMLS as a widely employed industrial process, especially for what concerns the production of moulds and inserts and allows their use only as preseries tools in injection moulding of plastics, since the requirements for preseries tools are worse than those needed during the process. Barrel finishing, in turn, is a well established technique to improve the roughness of parts of complicated shape by means of a soft mechanical action over the surface. The results herewith presented show that it is possible to achieve roughness of the order of 1 μm Ra even when starting from initial roughness of the order of 15 μm Ra, i.e. those typically attained by DMLS.

Reactive Atom Plasma for Rapid Figure Correction of Optical Surfaces

2011 ◽  
Vol 496 ◽  
pp. 182-187 ◽  
Author(s):  
Marco Castelli ◽  
Renaud Jourdain ◽  
Paul Morantz ◽  
Paul Shore
Keyword(s):  
Tool Path ◽  
Ion Beam ◽  
Experimental Tests ◽  
Scanning Speed ◽  
Fused Silica ◽  
Motion Path ◽  
Precision Engineering ◽  
Optical Surfaces ◽  
Reactive Atom ◽  
Spherical Hollow

Nanometre-scale figuring technique at atmospheric pressure for large optical surfaces is a high profile research topic which attracts numerous competing state-of-the-art technologies. In this context, a dry chemical process, called Reactive Atom Plasma (RAP), was developed as a prospectively ideal alternative to CNC polishing or Ion Beam Figuring. The RAP process combines high material removal rates, nanometre level repeatability and absence of subsurface damage. A RAP figuring facility with metre-scale processing capability, Helios 1200, was then established in the Precision Engineering Centre at Cranfield University. The work presented in this paper is carried out using Helios 1200 and demonstrates the rapid figuring capability of the RAP process. First experimental tests of figure correction are performed on fused silica substrates over 100 mm diameter areas. A 500 nm deep spherical hollow shape is etched onto the central region of 200x200 mm polished surfaces. The test is carried out twice for reproducibility purposes. After two iterative steps, a residual figure error of ~16 nm rms is achieved. Subsequently, the process is scaled up to 140 mm diameter areas and two tests are carried out. First, the developed algorithm for 500 nm deep spherical hollow test is confirmed. Residual deviation over processed area is ~18 nm rms after three iterations. Finally, a surface characterised by random topography (79 nm rms initial figure error) is smoothed down to ~ 16 nm rms within three iteration steps. All results presented in this paper are achieved by means of an in-house developed tool-path algorithm. This can be described as a staggered meander-type tool motion path specifically designed to reduce heat transfer and consequently temperature gradient on the surface. Contiguously, classical de-convolution methods are adapted to non-linear etching rates for the derivation of the surface scanning speed maps. The figuring procedure is carried out iteratively. It is noteworthy that iteration steps never exceed ~7 minutes mean processing time.

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.

Finite Element Analysis Within Component Design Process of Hydraulic Quadruped Robot

2014 ◽  
Author(s):  
Mariapaola D’Imperio ◽  
Ferdinando Cannella ◽  
Claudio Semini ◽  
D. G. Caldwell ◽  
Daniele Catelani ◽  
...  
Keyword(s):  
High Performance ◽  
Virtual Prototyping ◽  
Experimental Tests ◽  
Force Sensor ◽  
Quadruped Robot ◽  
Robot Design ◽  
Element Analysis ◽  
Sensor Optimization ◽  
The Third ◽  
Component Design

The lightweight constructions and components stiffness play an important role in mechanics and in particular in high performance robots. In this paper the Virtual Prototyping Design (VPD) approach for addressing the robot design to this goal is shown. The VPD is applied to three mechanical problems of Walking Hydraulic Robots (WHRs): the first one deals with the leg joint sensitivity analysis; the second one concerns a force sensor optimization while the third one presents the torso structural verification. In all the aforementioned studies the experimental tests and the fitting analyses for model validation were carried out reaching satisfactory results.

Integrated Application of RP and FEM to Support "One of a Kind" Component Design Using Prototyped Materials

2012 ◽  
Vol 730-732 ◽  
pp. 531-536
Author(s):  
Felipe Meneguzzo Pasquali ◽  
Deives Roberto Bareta ◽  
Leandro Luis Corso ◽  
Carlos Alberto Costa
Keyword(s):  
Finite Element ◽  
Geometric Model ◽  
Experimental Tests ◽  
Element Model ◽  
Support Design ◽  
Physical Test ◽  
Software Application ◽  
Component Design ◽  
Commercial Technology ◽  
Initial Results

This paper discusses the integrated use of rapid prototyping commercial technology and finite element method to support design of engineering components. The study was carried out on PolyJet RP technology. The resin properties were investigated by standard tests (ASTM) and used as input data on Abaqus software application. The results of the physical test were used to calibrate and validate the finite element model. Experimental tests were executed capturing critical loads and main forces acting on the geometric model and compared with the virtual model. The results showed small percentage differences between the physical and virtual models. Viscoelasticity of the resin was also detected in the analyzed physical model. Initial results have shown that the integration of these two technologies can assist in developing functional products, considering the technical limitations of the current prototype materials.

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