ROUGH MACHINING FOR MULTI-SCULPTURED SURFACES

1999 ◽  
Vol 23 (2) ◽  
pp. 275-286
Author(s):  
A. Vafaeesefat ◽  
H.A. EIMaraghy
Keyword(s):  
Cutting Planes ◽  
Tool Path ◽  
Tool Path Generation ◽  
Parallel Projection ◽  
Geometric Description ◽  
Sculptured Surfaces ◽  
Rough Machining ◽  
Tool Paths ◽  
Rough Milling ◽  
Bounding Surfaces

This paper present a method to generate 3-axis NC programs for rough milling processes. A raster digitizing of the solid volume delimitated by sculptured surfaces to be machined is first created. This is accomplished by using the so-called Z-buffer created from a parallel projection of all surfaces. Conventional rendering software can be used to generate the Z-buffer. This volume is transformed into a 3-D mesh composed of “empty”, “full”, and “mixed” blocks. Machining is preformed from top to bottom in a sequence of horizontal cutting planes. At each level of planar machining, spiral routines are used to generate the tool path. The proposed method is valid for generating tool paths for general cavities bounded by arbitrary surfaces. One of the notable advantages of the proposed method is that the tool path generation is independent from the geometric description of bounding surfaces. An example is used to illustrate the approach and its advantages.

A high-efficiency rough milling strategy for mould core machining

2003 ◽  
Vol 217 (3) ◽  
pp. 335-348 ◽  
Author(s):  
K W Chan ◽  
W K Chiu ◽  
S T Tan ◽  
T N Wong
Keyword(s):  
Convex Hull ◽  
Tool Path ◽  
High Efficiency ◽  
Core Layer ◽  
Layer By Layer ◽  
Rough Machining ◽  
Productivity Improvement ◽  
Tool Paths ◽  
Contour Parallel Tool Path ◽  
Rough Milling

Increasing the efficiency of rough machining operations can produce significant productivity improvement in mould and die making because most of the metal is removed in the roughing stage. In this paper, a high-efficiency 2.5-dimensional rough milling strategy for mould core machining is presented. The strategy consists of three different tool paths. The first tool path is generated on the basis of the convex hull boundary of a machining region. Owing to the absence of concave tool path segments, the convex hull based tool path can eliminate the chip load fluctuation problem encountered in corner cutting. The second tool path is an enhanced unidirectional straight-line tool path, which has the virtue of maintaining a steady cutting resistance throughout. The large staircases left behind by these two tool paths are refined by using the third tool path which is a contour-parallel tool path that cuts the mould core layer by layer in an upward manner. After applying these three tool paths, the stock material left on the mould core surface can be post-processed by the subsequent finish milling operation. A case study is illustrated to demonstrate the practicality of the presented rough milling strategy.

scholarly journals Precision Sculptured Surface CNC Machining Using Cutter Location Data

2016 ◽  
Vol 686 ◽  
pp. 224-233
Author(s):  
Nikolaos A. Fountas ◽  
Nikolaos M. Vaxevanidis ◽  
Constantinos I. Stergiou ◽  
Redha Benhadj-Djilali
Keyword(s):  
Tool Path ◽  
Low Cost ◽  
Cnc Machining ◽  
Sculptured Surface ◽  
Sculptured Surfaces ◽  
Rough Machining ◽  
Machining Error ◽  
Location Data ◽  
Tool Paths ◽  
Cutter Location Data

Industrial parts with sculptured surfaces are typically, manufactured with the use of CNC machining technology and CAM software to generate surface tool paths. To assess tool paths computed for 3-and 5-axis machining, the machining error is evaluated in advance referring to the parameter controlling the linearization of high-order curves, as well as the scallop yielded as a function of radial cutting engagement parameter. The two parameters responsible for the machining error are modeled and corresponding cutter location data for tool paths are utilized to compare actual trajectories with theoretical curves on a sculptured surface assessing thus the deviation when virtual tools are employed to maintain low cost; whilst ensuring high precision cutting. This operation is supported by applying a flexible automation code capable of computing the tool path; extracting its CL data; importing them to the CAD part and finally projecting them onto the part’s surface. For a given tolerance, heights from projected instances are computed for tool paths created by changing the parameters under a cutting strategy, towards the identification of the optimum tool path. To represent a global solution rough machining is also discussed prior to finish machining where the new proposals are mainly applied.

Dynamic In-Process Stock Based Tool Path Generation for High Surface Finish Rough Machining

2013 ◽  
Vol 567 ◽  
pp. 59-65
Author(s):  
Song Lin Ding ◽  
John P.T. Mo ◽  
Daniel Yang
Keyword(s):  
Surface Finish ◽  
Process Model ◽  
Tool Path ◽  
High Surface ◽  
Tool Path Generation ◽  
Path Generation ◽  
Rough Machining ◽  
Machining Time ◽  
Additional Tool ◽  
Tool Paths

This paper presents a new tool path generation strategy for rough machining based on the dynamic in-process stock model of the workpiece. Compared to conventional roughing method, the new tool paths result in a better surface finish but consume the same machining time. The cutter locations in the tool path are determined by removing the peak portion of the residual materials on the stock. The geometric information of remaining stocks is updated dynamically in the in-process model once each cutting pass is completed. The overall machining time is no longer than the conventional method since no additional tool paths are added. The proposed method was implemented in Catia and has been validated by simulation and cutting tests with flat end and ball nose cutters on a 3-axis CNC milling machine.

Study of The Tool Path Generation Method of an Ultra-Precision Spherical Complex Surface Based on a Five-Axis Machine Tool

2021 ◽  
Author(s):  
Tianji Xing ◽  
Xuesen Zhao ◽  
Zhipeng Cui ◽  
Rongkai Tan ◽  
Tao Sun
Keyword(s):  
Surface Roughness ◽  
Tool Path ◽  
Spherical Surface ◽  
Tool Path Generation ◽  
Path Generation ◽  
Tool Paths ◽  
Spherical Surfaces ◽  
Spherical Complex ◽  
Ultra Precision ◽  
Five Axis

Abstract The improvement of ultra-precision machining technology has significantly boosted the demand for the surface quality and surface accuracy of the workpieces to be machined. However, the geometric shapes of workpiece surfaces cannot be adequately manufactured with simple plane, cylindrical, or spherical surfaces because of their different applications in various fields. In this research, a method was proposed to generate tool paths for the machining of complex spherical surfaces based on an ultra-precise five-axis turning and milling machine with a C-Y-Z-X-B structure. Through the proposed tool path generation method, ultra-precise complex spherical surface machining was achieved. First, the complex spherical surface model was modeled and calculated, and then it was combined with the designed model to generate the tool path. Then the tool paths were generated with a numerically controlled (NC) program. Based on an ultra-precision three-coordinate measuring instrument and a white light interferometer, the machining accuracy of a workpiece surface was characterized, and t[1]he effectiveness of the provided tool path generation method was verified. The surface roughness of the machined workpiece was less than 90 nm. Furthermore, the surface roughness within the spherical region appeared to be less than 30 nm. The presented tool path generation method in this research produced ultra-precision spherical complex surfaces. The method could be applied to complex spherical surfaces with other characteristics.

Use of a virtual milling system to generate power-aware tool paths for 2.5-dimensional pocket machining

2019 ◽  
Vol 233 (13) ◽  
pp. 2419-2435 ◽  
Author(s):  
David Manuel Ochoa González ◽  
Joao Carlos Espindola Ferreira
Keyword(s):  
Power Consumption ◽  
Tool Path ◽  
Tool Path Generation ◽  
Path Generation ◽  
Machining Time ◽  
Power Requirement ◽  
Pocket Machining ◽  
Direction Parallel ◽  
Generation Algorithm ◽  
Tool Paths

Traditional (direction-parallel and contour-parallel) and non-traditional (trochoidal) tool paths are generated by specialized geometric algorithms based on the pocket shape and various parameters. However, the tool paths generated with those methods do not usually consider the required machining power. In this work, a method for generating power-aware tool paths is presented, which uses the power consumption estimation for the calculation of the tool path. A virtual milling system was developed to integrate with the tool path generation algorithm in order to obtain tool paths with precise power requirement control. The virtual milling system and the tests used to calibrate it are described within this article, as well as the proposed tool path generation algorithm. Results from machining a test pocket are presented, including the real and the estimated power requirements. Those results were compared with a contour-parallel tool path strategy, which has a shorter machining time but has higher in-process power consumption.

A novel tool-path generation method for five-axis flank machining of centrifugal impeller with arbitrary surface blades

2016 ◽  
Vol 231 (1) ◽  
pp. 155-166 ◽  
Author(s):  
Hong-Zhou Fan ◽  
Shang-Jin Wang ◽  
Guang Xi ◽  
Yan-Long Cao
Keyword(s):  
Tool Path ◽  
Tool Path Generation ◽  
Ruled Surface ◽  
Centrifugal Impeller ◽  
Flank Milling ◽  
Path Generation ◽  
Rough Machining ◽  
Machining Time ◽  
Geometrical Structures ◽  
Five Axis

The centrifugal impeller with arbitrary surface blades is a very important component in automobile, ships, and aircraft industry, and it is one of the most difficult parts to process. Focusing on the machining efficiency improvement, combining the geometric advantages of ruled surface and arbitrary surface, and utilizing the efficient and accurate advantages of flank machining and point machining, this article presents a novel and targeted tool-path generation method and algorithm for five-axis flank machining of centrifugal impeller with arbitrary surface blades. In light of specific characters of different surfaces, the analyses of two different impeller blades are proposed first, the more characteristic and complex geometrical structures of the arbitrary blade are achieved. In rough machining, an approximate ruled surface blade is obtained, and a simple channel is achieved; the flank milling of the centrifugal impeller with ruled surface blades is achieved relative to the point milling of the centrifugal impeller with arbitrary surface blades; and the triangle tool path planning method is added in this process to save the machining time and cost collectively. Furthermore, in semi-finish machining, the approximate sub-ruled blade surfaces are calculated, and a new flank milling method of the sub-ruled blade surfaces is achieved; a new solution for tool interference is achieved in this process and the generation of non-interference tool paths becomes easy. Machining experiments of two different impellers are presented as a test of the proposed methods.

An Efficient, Accurate Approach to Representing Cutter-Swept Envelopes and Its Applications to Three-Axis Virtual Milling of Sculptured Surfaces

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Zezhong C. Chen ◽  
Wei Cai
Keyword(s):  
Tool Path ◽  
Basic Mechanism ◽  
Cnc Milling ◽  
Sculptured Surfaces ◽  
Machining Error ◽  
Tool Paths ◽  
Virtual Machining ◽  
Machining Errors ◽  
Computer Numerically Controlled ◽  
Swept Volume

To address a major technical challenge in simulating geometric models of machined sculptured surfaces in three-axis virtual machining, this paper presents an efficient, accurate approach to representing the 3D envelopes of a cutter sweeping sequentially through cutter locations; these envelopes embody the furrow patches of the machined surfaces. In our research, the basic mechanism of removing stock material in three-axis computer numerically controlled (CNC) milling of sculptured surfaces is investigated, and, consequently, an effective model is proposed to represent the 3D envelopes (or furrow patches). Our main contribution is that a new directrix (or swept profile) of the furrow patches (mathematically, ruled surfaces) is identified as a simple 2D envelope of cutting circles and is formulated with a closed-form equation. Therefore, the 3D cutter-swept envelopes can be represented more accurately and quickly than the existing swept-volume methods. With this innovative approach, a method of accurate prediction of the machining errors along tool paths in three-axis finish machining is provided, which is then applied to the optimization of tool-path discretization in two examples. Their results demonstrate the advantages of our approach and verify that the current machining-error-prediction methods can cause gouging in three-axis sculptured surface milling.

Sheet Metal Laser Cutting Tool Path Generation: Dealing with Overlooked Problem Aspects

2015 ◽  
Vol 639 ◽  
pp. 517-524 ◽  
Author(s):  
Reginald Dewil ◽  
Pieter Vansteenwegen ◽  
Dirk Cattrysse
Keyword(s):  
Penalty Function ◽  
Laser Cutting ◽  
Tool Path ◽  
Cutting Tool ◽  
Tool Path Generation ◽  
Metal Sheet ◽  
Path Generation ◽  
Plate Edge ◽  
Tool Paths ◽  
Easy Problem

This paper deals with non-trivial problem aspects of laser cutting tool path generation that, to the best of our knowledge, received relatively little attention in the scientific literature. It is shown that some aspects such as plate edge nesting, skeleton and remnant cutting, and clamp positioning can be modeled and solved with little additional effort using existing tool path algorithms. However, concepts such as collision avoidance, pre-cut optimization, and bridge utilization prove to be more challenging and will require more profound algorithmic adjustments if these have to be taken into account fully. An even harder problem aspect is generating tool paths that are thermally feasible. Since laser cutting introduces net heat into the metal sheet, the metal sheet tends to heat up as the cutting progresses. Quality deterioration can occur if the laser spends too much time cutting in the same region. It is shown how to model the easy problem extensions in order to handle them using existing problem approaches and solution approaches are suggested to tackle the harder concepts. In addition, a proof of concept is presented that shows that thermal feasible tool paths can be generated through a multi-start heuristic utilizing a thermal penalty function. A finite difference method iteratively (or concurrently dependent on the used heuristic) evaluates the thermal feasibility and updates the penalty function.

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