基于压缩体素模型的球头刀空间扫描体构造新方法及其应用

A new compressed voxel-based method for swept volume modeling of a ball-end cutting tool and its application

提出了一种基于压缩体素模型的球头刀空间扫描体构造新方法,将球头刀分解为相应球体部分和圆柱体部分,分别给出了球体和圆柱体空间扫描体构造公式并构造出其表面模型,利用RayCasting方法分别将球体和圆柱体空间扫描体表面模型进行离散,将其分别转化为压缩体素模型,通过布尔并操作生成球头刀空间扫描体压缩体素模型。该方法由于采用三个方向的Dexel模型表示体素模型,其计算机内部存贮空间得到了很大地压缩,并简化了布尔操作和提高了布尔操作速度;通过MarchingCubes方法提取数控加工仿真工件表面模型并进行图形显示,提高了显示质量和显示速度。该方法在《基于压缩Voxel模型的五坐标数控加工仿真系统》中得到了应用并完成了某叶轮的五坐标数控加工仿真,仿真结果三维信息完备,NC编程人员可从任意方向观察、验证仿真结果,克服了现有五坐标数控加工仿真方法和商品化软件系统的不足,该方法是虚拟数控加工的关键技术。

Geometric modeling of swept volume of a cutting Tool is important in numerical control simulation. Based on the compressed voxel model, we presents a new method for swept volume modeling of a ball-end cutting tool. First, a ball-end cutting tool is separated into two portions： a sphere and a cylinder; then the swept surface models of the sphere and cylinder are calculated and divided into compressed voxel model by the Ray Casting method separately; Finally, the Boolean operations are used to model the swept volume of the ballend cutting tool. We utilize the dexel model in three directions to represent a voxel model. This algorithm can greatly save the storage and simplify the Boolean operations. We also discuss the visualization of the compressed voxel model and propose an optimal surface extraction method based on the Marching Cubes algorithm. This method was applied in Five-axis NC simulation system base on compressed voxel model, which has gained excellent effect. The disadvantages of current five-axis NC simulation method and commercial software systems are overcome. The method is the key technology for the virtual numerical control machining.