Hu Zhu

An Overview of the Sheet Metal CNC Incremental Forming Toolpath Generation

The sheet metal CNC incremental forming is a flexible dieless forming technology that forms a sheet part by extruding the sheet metal point by point with the movement of forming tool along the forming path. The tool paths therefore have a great effect on the dimensional accuracy, surface quality and forming time. In this paper, an overview of the research status about the forming tool path generation for sheet metal CNC incremental forming is presented briefly.

3D Laser Inner Engraving Path Generation and Simulation for Crystal Glass

The method of laser inner engraving path generation and simulation for crystal glass is presented based on STL(Stereo Lithography) model. To generate the laser exposure points that are adaptive to the surface of model, the contour lines are obtained by cutting the STL model with unequal distance using a series of plans that are perpendicular to Z-axis. Then the contour lines are offset and scattered, and then the path is generated by sorting and connecting each discrete point in order. Simultaneously, simulation method of laser inner engraving for crystal glass is also proposed. The case studies show that the method can primely realize the engraving path generation and the simulation for the laser inner engraving of crystal glass, and that the system runs stably and reliably.

A Study on the Interference Checking in CNC Incremental Forming Based on Parasolid

The squeezing tool in 5-axis CNC incremental forming has more degrees of freedom and can squeeze the sheet metal along the reasonable direction, thus better forming effect is obtained. While in the process of 5-axis CNC incremental forming the interference between squeezing tool and workpiece occurs frequently because of the continual posture change of squeezing tool. Therefore the interference checking method of squeezing tool and workpiece is studied in this paper. The interference is checked out through the collision calculation of established squeezing tool solid models of different posture and workpiece solid model based on Parasolid modeling kernel. The case study shows that the method can check the interference between the squeezing tool and workpiece very well.

Generation of Technological Model for Multi-Stage Incremental Forming

In order to the difficult forming sheet metal part with the vertical wall to be formed by the multi-stage incremental forming, the algorithm of the recognition and modify the difficult forming surface of the vertical wall is studied. The method for generation of the technological model for multi-stage incremental forming is also presented. The case studies show that the algorithm is feasibility.

Research on the Forming Path for Fabricating the Sheet-Metal Part with Non-Horizontal End Face Using CNC Incremental Forming

For the purpose of the fabrication of the sheet-metal parts with non-horizontal end face using the sheet metal CNC incremental forming technology, two kinds of path generating methods, namely the level path perpendicular to Z axis method and the equidistant path parallel to sheet metal are proposed in this paper. Both of the paths are generated by Visual C++ and OpenGL graphics library, the effect of the two kinds of forming paths to the forming quality of the sheet part with non-horizontal end face is researched using the finite element analysis method in this paper.

Generation of the Underdraught Points Uniformly Distributed Contour Tool Path for CNC Incremental Forming

Aiming at the problem that indentation was generated on the forming surface due to the concentration of underdraught points on contour tool path, this paper proposed a method that can obtain a series of uniformly-distributed underdraught points on the contour tool path generated based on STL model in sheet metal CNC incremental forming. In this algorithm the STL model was taken as the input model and the cutting plane through the central rotation axis of model was rotated a certain angle in turn to cut the contour tool path, then the underdraught points distributed uniformly along the workpiece contour can be obtained. The case study shows that the proposed method can effectively generate the contour tool path with the underdraught points uniformly distributed.

The Control of the Gap between Tool and Support, and the Analysis of its Effect on the Accuracy of CNC Incremental Forming

Two kinds of methods for the control of the gap between pressing tool head and support in CNC incremental forming have been discussed (i.e. pressing path adjustment method and support shape adjustment method), and whose effects on forming accuracy are analyzed by using the Finite Element Analyses. The methods for the generation of pressing paths and supports have been given for the two forming method of the pressing path adjustment and support shape adjustment, and the Finite Element Analysis models have been built for them respectively. The method of digital simulations for the two forming cases mentioned above based on the ANSYS/LS-DYNA software has been presented and the forming precision of the two forming methods are analyzed through the comparison of digital simulation results.

An Overview of STL Model Offset

The offset models of STL (Stereo Lithography) are useful in many applications such as interference-free tool path generation in numerical control machining, hollow or shelled model generation in rapid prototyping. So the methods for STL model offset are very important. In the paper, an overview of the STL models offset methods is presented in brief.

Heating Path Generation and Simulation for Ship Plate Steel

To lay the foundation of the automation for line heating forming, a method for heating path generation and simulation for ship plate steel base on STL mode was proposed in this paper. The line heating path was generated by slicing the STL model of the steel plate using a series of planes, and the models of the heating equipment of ship plate steel were build, and the heating process of ship plate steel can be simulated by inputting the models of the heating equipment into the simulation system that was built by using VC++ and OpenGL. The case study shows that the method can primely solve the inconvenient of manual heating and the whole heating process can be observed by the simulation so that the heating process can be made a reasonable monitoring, and the heating path generation and simulation software are runs stably and reliably.

A CAD/CAM System for Integrated Process of CNC Incremental Forming and 5-Axis Laser Cutting

The sheet metal forming is widely used in aerospace, automobile and shipbuilding industry. CNC incremental forming is a kind of recently developed flexible and dieless forming technology. This paper introduce an integrated process of CNC incremental forming and 5-axis laser cutting based on machining features, and the structure of related special CAD/CAM system as well as its development methods.