Generation of Regularly Aligned Curved Surface Patches on Free-Form Surface for Patch Division Milling

2012 ◽  
Vol 523-524 ◽  
pp. 54-57
Author(s):  
Kai Xu ◽  
Hiroyuki Sasahara

This study describes a new machining strategy to make regularly aligned cutter marks on free-form surface efficiently for increasing the added value of industrial product. While the free-form surface is divided into many small patch segments employing curved surface patch division milling technique which can substitute for the conventional method, thus avoiding the influence of the change in the curvature. And the patch segments will be machined by a spiral tool path respectively, so that regularly aligned cutter marks can be successfully formed on the curved surface patches by controlling cross-feed, feed speed per tooth, number of teeth and the length of the tool path. Comparing the machined surface and the simulation result, the cutter marks agree with it. If the surface is machined only by the ball end milling with a machining center, this method will be a very effective tool for the machinery industry.

2016 ◽  
Vol 10 (1) ◽  
pp. 23-29
Author(s):  
Kai Xu ◽  
◽  
Hiroyuki Sasahara ◽  

Many products are designed with surface textures that enhance the aesthetic and tactile qualities of the product. In this paper, a curved-surface, patch-division milling technique is proposed for creating uniform aligned cutter marks on a curved surface. Previous research demonstrated a ball-end milling technique that divides the surface into small planar patches where each patch is generated by a helical tool path with dimples in uniform alignment. Because the patches are planar, it is impossible to precisely machine a concave or convex surface. However, the technique could only approximate a method for machining curved surfaces. To resolve this issue, curved surface patches were developed to generate the patch directly according to the shape of the targeted curved surface. The dimples are expected to be uniformly aligned on curvedsurface patches. Therefore, the targeted surface should be cut using an appropriate machining condition. According to the test results, the distribution of dimples was the same as the pre-determined distribution. In addition, the dimples were regularly aligned when viewed from a specific angle. This proposed method overcomes the deviation of the dimple's positions, which is caused by the acceleration--deceleration of the machine tool and the change of the cutting point during five-axis machining.


2010 ◽  
Vol 102-104 ◽  
pp. 544-549 ◽  
Author(s):  
Chun Jiang Zhou ◽  
Hong Chun Chen

The development of surface high-speed machining has put forward higher demands for uniform cutting load and smooth cutting tool path. Most current tool-path planning methods are based on constant scallop height, but they have the disadvantage of path point redundancy during the path discretization process. To overcome the problem, a tool path generation method of equal approximation error in each step for free-form surface is presented based on geodesic principle and curvature judgment. In this method, the NURBS curve is employed to realize smooth transition for adjacent two tool paths in high-speed machining. A certain angle of inclination of flat-end milling cutter during multi-axis machining improves the machining efficiency. Because of the advantage of this machining condition, the cutter location point generation algorithm during the machining condition is given by the method. The method is verified and simulated by C++. Experiment results proved that it can obtain uniform cutting load and continuous smooth cutting tool path during surface high-speed machining by the proposed method.


2019 ◽  
Vol 13 (5) ◽  
pp. 679-690 ◽  
Author(s):  
Takamaru Suzuki ◽  
Kazuki Yoshikawa ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Takakazu Ikegami ◽  
...  

A 5-axis machining center (5MC) is noted for its synchronous control capability, making it a feasible tool for quickly and accurately machining complicated three-dimensional surfaces such as propellers and hypoid gears as it is equipped with a direct-drive (DD) motor in the rotary axis. The current research work identified the necessity of improving both the accuracy of the machined shape and the consistency of the free-form machined surface. A method for maintaining the feed speed vector at the milling point by controlling two linear axes and the rotary axis of a 5MC to improve the quality of the machined surface was investigated. Additionally, a method was proposed for reducing the shape error of machined workpieces by considering differences in the servo characteristics of the three axes. The shape error was significantly reduced by applying the proposed method using a precedent control coefficient determined via calculations. To maintain the feed speed vector at the milling point in the machining of complex shapes, rapid velocity change in each axis is often required, leading to inaccuracy caused by torque saturation at a DD motor in the rotary axis. The results of this study indicate that torque saturation can be evaluated via simulation and that the machining accuracy and consistency can be improved by accounting for these errors using the proposed precedent control coefficient method.


2000 ◽  
Vol 123 (1) ◽  
pp. 74-82 ◽  
Author(s):  
C. Bradley ◽  
V. Chan

A complementary sensor technique for reverse engineering objects that are represented by a three-dimensional (3D) cloud data set is reported. The research focuses on objects whose surface form is manifest as a set of distinct free-form surface patches, each of which is enclosed by a boundary. The method incorporates three stages: (1) laser scanner-based digitization of all the free-form surface patches, (2) touch probe-based digitization of the surface patch boundaries, and (3) modeling of both data sets to create a complete B-spline curve and surface representation of the object. The patch boundary data, defined by the touch probe, is employed to segment the free-form surface data into the constituent patches. Furthermore, the boundary data is incorporated within a B-spline surface fitting process to constrain the boundaries. The two sensors functionally complement each other; the range sensor provides the required dense resolution of 3D points on the free-form surfaces whereas the touch probe accurately defines the patch boundaries. The method is ideal for objects comprised of both functional engineering features, e.g. bearing holes or precise mounting locators, and aesthetic features, such as hand grips or part covers. The touch probe is also ideal for digitizing boundaries where occlusion prevents the use of an optical digitizer. The laser-based sensor has an accuracy specification of 50 microns (over a 40-mm depth of field) whereas the touch probe is accurate to 4 microns over a 25-mm measurement length. An example part is modeled that has multiple free-form patches (defining the part’s outer cover) that require a large cloud data set for complete coverage. The corresponding patch boundaries accurately define the location of critical part mounting locations that require the touch probe’s precision.


Author(s):  
Tomonobu Suzuki ◽  
Koichi Morishige

Abstract This study aimed to improve the efficiency of free-form surface machining by using a five-axis controlled machine tool and a barrel tool. The barrel tool has cutting edges, with curvature smaller than the radius, increasing the pick feed width compared with a conventional ball end mill of the same tool radius. As a result, the machining efficiency can be improved; however, the cost of the barrel tool is high and difficult to reground. In this study, a method to obtain the cutting points that make the cusp height below the target value is proposed. Moreover, a method to improve the tool life by continuously and uniformly changing the contact point on the cutting edge is proposed. The usefulness of the developed method is confirmed through machining simulations.


Author(s):  
Yuan-Shin Lee ◽  
Tien-Chien Chang

Abstract In this paper, a methodology of applying convex hull property in solving the tool interference problem is presented for 5-axis NC machining of free-form surfaces. Instead of exhausted point-by-point checking for possible tool interference, a quick checking can be done by using the convex hull constructed from the control polygon of free-form surface modeling. Global tool interference in 5-axis NC machining is detected using the convex hull of the free-form surface. A correction method for removing tool interference has also been developed to generate correct tool path for 5-axis NC machining. The inter-surface tool interference can be avoided by using the developed technique.


2014 ◽  
Author(s):  
Nandkumar N. Bhopale ◽  
Raju S. Pawade

The paper presents the surface integrity analysis in ball end milling of thin shaped cantilever plate of Inconel 718. It is noticed that the workpiece deflection has significantly contributed to machined surface integrity in terms of surface topography and subsurface microhardness. The ball end milling performed with 15° workpiece inclination with horizontal tool path produced higher surface integrity which varies with the location of machined surface region. In general, the mid portion of the machined plate shows lower surface roughness and microhardness with less surface defects.


Author(s):  
Feiyan Han ◽  
Juan Wei ◽  
Bin Feng ◽  
Wu Zhang

The manufacturing technology of an integral impeller is an important indicator for measuring the manufacturing capability of a country. Its manufacturing process involves complex free-form surface machining, a time consuming and error-prone process, and the tool path planning is considered as a critical issue of free-form surface machining but still lacks a systematic solution. In this paper, aiming at the tool path planning of the impeller channel, a quasi-triangular tool path planning method based on parametric domain template trajectory mapping is proposed. The main idea is to map the template trajectory to physical domain by using the mapping model of parametric domain to the physical domain to obtain the actual machining path. Firstly, the trajectory mapping model of parametric domain to physical domain is established using the morphing technique, and the template trajectory mapping method in the parametric domain is given. Secondly, the clean-up boundary of the impeller channel is determined in the parametric domain, and the quasi-triangular template trajectory of the impeller channel is defined. Finally, taking a certain type of impeller as an example, the quasi-triangular tool path of the impeller channel is calculated, and the tool path calculation time of this method is compared with that of the traditional isometric offset method. The result shows that the computational efficiency is improved by 45% with this method, which provides a new method for the rapid acquisition of NC machining tool path for impeller channels. In addition, the simulation and actual machining are carried out, the results show that the shape of actual cutting traces on the surface of the impeller channel is quasi-triangular, showing that this method is effective and feasible.


Author(s):  
Yuki Takanashi ◽  
Hideki Aoyama

Abstract Machining data (NC program) is generated by a CAM system, which generates the tool path from the target shape as a plane approximation surface instead of a free-form surface. Owing to this plane approximation, machining accuracy is reduced. In this paper, we propose a method to process the shape with high accuracy by defining the areas where accuracy is not required as a plane approximation surface and defining the part where accuracy is required as free-form surfaces.


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