Exploration of Local Blade Motions During Blade Shaping for Thick Layered Foam Cutting

2004 ◽  
Author(s):  
J. J. Broek ◽  
A. Kooijman
Keyword(s):  
Strain Energy ◽  
Cutting Tool ◽  
Cutting Speed ◽  
General Rule ◽  
Free Form ◽  
Linear Change ◽  
Minimum Strain Energy ◽  
Blade Cutting ◽  
Tool Position ◽  
Cutting Direction

The FF-TLOM (Free Form Thick Layered Object Manufacturing) technology is a Rapid Prototyping process based on flexible blade cutting of polystyrene foam. The heated blade is shaped by three parameters, which allows an infinite amount of minimum strain energy blade shapes with none, one or two inflexions. In the shaping domain stable and unstable blade shapes can exist. Stable shapes are defined as curves with none and one-inflexion and are applied for operational cutting of foam layers with the FF-TLOM technology. The tool motions are generated from the static tool poses and are calculated for a linear change of the flexible blade, when the cutting tool moves from one tool position to the next. The cutting blade is positioned to the foam slab with help of a point relative positioned on the flexible blade. The tool frame is positioned with a point fixed relatively to the tool frame. During the tool motions the blade curvature is changed and will introduce a shift of the half way point fixed on the blade (especially in the case of asymmetrical support inclinations and high curvature). Next the local displacement of the blade points in the bending plane of the blade due to blade shaping and tool pitching are quantified during the tool motions. These displacements induce an angle of attack of the blade in cutting direction, and will influence cutting speed and cutting accuracy. The quantification software is developed and will be used in the future for an overall prediction of the total tool curve displacements due to blade shaping, such as roll, pitch, yaw and linear positioning motions of the tool. A general rule for FF-TLOM cutting is minimization of all tool motions, which are not related to the forward cutting motion.

Speed Control for Flexible Blade Cutting of Thick Foam Layers

2002 ◽  
Author(s):  
J. J. Broek ◽  
I. Horva´th ◽  
A. Kooijman
Keyword(s):  
Manufacturing Process ◽  
Strain Energy ◽  
Tool Path ◽  
Estimation Method ◽  
Cutting Speed ◽  
Free Form ◽  
Energy Curve ◽  
Optimal Orientation ◽  
Blade Cutting ◽  
Manufacturing Time

The FF-TLOM (Free Form Thick Layered Object Manufacturing) process is based on heated flexible blade cutting of thick foam layers in a free form manner. Both blade ends are supported in a U-shaped tool frame. During cutting the blade is shaped in a minimal strain energy curve. Positioning the tool in an optimal orientation is provided by pitch, roll, yaw and positioning of the tool frame. A restriction of the FF-TLOM cutting is the cutting speed. The cutting speed depends on melting of the foam at the blade location and does not allow outside forces on the blade. Nevertheless the manufacturing time must be as rapid as possible. In this paper an estimation method is proposed for the overall speed setting along a tool path. Hereto the blade is subdivided in blade segments and each segment is analyzed for the encountered speed and in the same time to prevent that the maximum allowable cutting speed is exceeded.

Optimization Research on Geometric Parameters of Scallop-Shaped Lattice Shells

2015 ◽  
Vol 724 ◽  
pp. 192-196
Author(s):  
Na Li ◽  
Ren An Chang ◽  
Wei Zong ◽  
Qi Hang Yu
Keyword(s):  
Mechanical Properties ◽  
Strain Energy ◽  
Geometric Parameters ◽  
Free Form ◽  
Spatial Structures ◽  
Shaped Surface ◽  
Minimum Strain Energy ◽  
Optimal Values ◽  
Lattice Shells

<p>Free-form and bionic spatial shells are popular in the area of spatial structures. Scallop-shaped surface is the product of evolution and a kind of spatial shells that can satisfy the mechanical requirements. Based on the scallop-shaped lattice shells, this paper focused on the optimization of geometric parameters. The principle of minimum strain energy was applied to conclude the influence law of the geometric parameters on mechanical properties. Finally the optimal values of geometric parameters were obtained. The results show that the optimization of geometric parameters presents the integrated significance to improve scallop-shaped lattice shells.</p>

Matching Minimum Strain Energy Curves to B-Spline Curves for Thick Layer Manufacturing

2002 ◽  
Author(s):  
Adrie Kooijman ◽  
Joris S. M. Vergeest
Keyword(s):  
Strain Energy ◽  
Cutting Tool ◽  
Thick Layer ◽  
B Spline ◽  
Spline Curves ◽  
Layer Manufacturing ◽  
Point Density ◽  
Key Issues ◽  
Minimum Strain Energy ◽  
The Given

One of the key issues of thick layer manufacturing is matching the shape of the flexible cutting blade to the local surface curvature of the model to be created. In this paper we explore a method to find the best matching minimum strain energy (MSE) curve for a given B-spline curve. For this purpose we developed software to a) generate a dataset containing MSE curves for a range of settings of the cutting tool and b) find the best matching curve from this MSE dataset to the given target curve. Both the MSE and the target curves are represented as point sets, the target curves having a considerable higher point density than the curves in the MSE dataset. The best matching MSE curve is defined as the curve with the minimum directed Hausdorff distance to the target curve. It is found that despite the relative low density of the dataset, for several practical domains of target curve shape, a satisfying match can be found. Numerical results concerning the matching accuracy are presented.

L-Shaped Machining of Anisotropic Woods with a Fine Wire Cutting Tool

2015 ◽  
Vol 656-657 ◽  
pp. 314-319
Author(s):  
Satoshi Sakamoto ◽  
Yasuo Kondo ◽  
Kenji Yamaguchi ◽  
Keitoku Hayashi ◽  
Ryuichi Iida ◽  
...  
Keyword(s):  
Cutting Tool ◽  
Anisotropic Materials ◽  
Free Form ◽  
Fine Wire ◽  
Hand Tool ◽  
Wire Cutting ◽  
Wood Grain ◽  
Saw Blade ◽  
Free Form Surfaces ◽  
Cutting Direction

A fret-saw blade is commonly used in micromachining or curve machining of various woods. However, there is a curvature limit for machining of free-form surfaces because a fret-saw blade has a thickness of several hundred microns and a width of several millimeters. Additionally, cutting with a fret-saw blade produces much wood meal as chips. If a fine wire cutting tool is used, more flexible machining, such as machining of high curvature free-form surfaces, is possible and the quantity of chip production drastically decreases. The main purpose of this study is to clarify the fundamental machinability of anisotropic materials cut with a fine wire tool. In this report, we describe the machinability of various woods that are naturally anisotropic materials using a fine wire cutting tool that has electrodeposited diamond grains on its surface. In addition, this report discusses the performance of a trial manufactured hand tool employing the same wire cutting tool. The main conclusions obtained in this study are as follows. Acceptable machining of anisotropic woods is possible using a fine wire cutting tool, and the kerf width produced with this wire tool is narrower than that produced with a fret-saw blade. Additionally, the wood species and the cutting direction with respect to the wood grain have a significant influence on the machinability of various woods. Moreover, a relatively smooth cross section is provided when wood is cut by the hand tool using the fine wire tool.

Shaping Minimum Strain Energy Curves for FF-TLOM

2003 ◽  
Author(s):  
J. J. Broek ◽  
A. Kooijman ◽  
A. de Smit ◽  
I. Horva´th
Keyword(s):  
Strain Energy ◽  
Tool Path ◽  
Computing Time ◽  
Free Form ◽  
Energy Curve ◽  
Calculation Algorithm ◽  
Path Creation ◽  
Blade Shape ◽  
Minimum Strain Energy ◽  
A Chain

Free Form Thick Layered Object Manufacturing (FF-TLOM) technology is based on foam cutting with a curved heated flexible cutting blade. Three single parameters shape the flexible blade. An infinite amount of blade shapes can be selected. However, many of these shapes are not suitable for cutting. Blade shapes with less than two inflexions can be applied successfully. When two inflexions are involved the blade; more than one different stable blade shape can be realized. For tool path creation and cutting procedures the blade shape must be known. A 2-D calculation algorithm based on (Kallay, 1987) is used. The calculation result is a minimum strain energy curve of a prescribed length, which is represented by a chain of segments. The shape is unfolded by rotating each segment under conditions of total energy decrease until no improvements are achieved. In this paper the process parameters are analyzed for sensitivity and influence on the accuracy and conditions of the blade shaping process. An overview of these parameters is given and the accuracy, computing time and trustworthiness of the implemented algorithm is checked. Typical FF-TLOM process characteristics are considered for its influence on the blade shape The elastic energy of curves is presented for a complete range of blade shapes. Regions of bi-stable blade shapes are perceived based on more than one blade inflexion. Finally a selection is presented for those minimum strain curves, which are applicable for the FF-TLOM technology.

Effects of Vibration on the Preparation of Ultrathin Sections

1973 ◽  
Vol 31 ◽  
pp. 358-359
Author(s):  
Joseph M. Blum ◽  
Edward P. Gargiulo ◽  
J. R. Sawers
Keyword(s):  
Cutting Speed ◽  
Ground Level ◽  
Environmental Vibration ◽  
Block Face ◽  
Ultrathin Sections ◽  
Embedding Medium ◽  
Thickness Variations ◽  
Building Walls ◽  
Cutting Direction ◽  
Diamond Knife

It is now well-known that chatter (Figure 1) is caused by vibration between the microtome arm and the diamond knife. It is usually observed as a cyclical variation in “optical” density of an electron micrograph due to sample thickness variations perpendicular to the cutting direction. This vibration might be induced by using too large a block face, too large a clearance angle, excessive cutting speed, non-uniform embedding medium or microtome vibration. Another prominent cause is environmental vibration caused by inadequate building construction. Microtomes should be installed on firm, solid floors. The best floors are thick, ground-level concrete pads poured over a sand bed and isolated from the building walls. Even when these precautions are followed, we recommend an additional isolation pad placed on the top of a sturdy table.

scholarly journals Analysis of Elastic Deflection of Single Point Cutting Tool and Optimization of Cutting Speed in Turning Operation by Using MADM Method

2021 ◽  
Vol 1104 (1) ◽  
pp. 012017
Author(s):  
Saurabh Dewangan ◽  
Somnath Chattopadhyaya ◽  
Amar Sharma ◽  
Varun Chaudhary ◽  
Ritwik Rohan
Keyword(s):  
Cutting Tool ◽  
Single Point ◽  
Cutting Speed ◽  
Turning Operation ◽  
Elastic Deflection

Experimental investigation of a slip-line field model for a worn cutting tool

2013 ◽  
Vol 228 (8) ◽  
pp. 1398-1404 ◽  
Author(s):  
Alper Uysal ◽  
Erhan Altan
Keyword(s):  
Wear Rate ◽  
Slip Line ◽  
Field Model ◽  
Cutting Tool ◽  
Flank Wear ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Rake Angle ◽  
Uncut Chip Thickness ◽  
Line Field

In this study, the slip-line field model developed for orthogonal machining with a worn cutting tool was experimentally investigated. Minimum and maximum values of five slip-line angles ( θ1, θ2, δ2, η and ψ) were calculated. The friction forces that were caused by flank wear land, chip up-curl radii and chip thicknesses were calculated by solving the model. It was specified that the friction force increased with increase in flank wear rate and uncut chip thickness and it decreased a little with increase in cutting speed and rake angle. The chip up-curl radius increased with increase in flank wear rate and it decreased with increase in uncut chip thickness. The chip thickness increased with increase in flank wear rate and uncut chip thickness. Besides, the chip thickness increased with increase in rake angle and it decreased with increase in cutting speed.

Crack Driving Force in Anisotropic Media due to Non-Elastic Deformation

2004 ◽  
Vol 261-263 ◽  
pp. 75-80
Author(s):  
G.H. Nie ◽  
H. Xu
Keyword(s):  
Elastic Deformation ◽  
Driving Force ◽  
Strain Energy ◽  
Elastic Stress ◽  
Complex Function ◽  
Crack Driving Force ◽  
Special Cases ◽  
Degree Of Anisotropy ◽  
Minimum Strain Energy ◽  
Orthotropic Media

In this paper elastic stress field in an elliptic inhomogeneity embedded in orthotropic media due to non-elastic deformation is determined by the complex function method and the principle of minimum strain energy. Two complex parameters are expressed in a general form, which covers all characterizations of the degree of anisotropy for any ideal orthotropic elastic body. The stress acting on the long side of ellipse can be considered as a crack driving force and applied in failure and fatigue analysis of composites. For some special cases, the resulting solutions will reduce to the known results.

Sign in / Sign up

Export Citation Format

Share Document