Comparison of Toolpath Modes and Machining Characteristics in CNC Engraving

In this study, 6 toolpath modes(paralled contouring, z-level profiling, radial toolpath, surface flowline machining, offset coutouring, angular partition machining) available in JDPaint software were compared through carving experiments on thuja. The differences in processing time, toolpath, and surface quality were systematically evaluated. The aim is to provide a reference for selecting toolpaths and optimizing parameters in CNC engraving of other materials, such as jadeite and other hard gemstones. This work also serves as a pilot study for optimizing technical parameters in CNC engraving of hard jades. The results demonstrated that the parallel contouring mode offers a balanced performance in terms of efficiency and quality, making it the most widely adopted strategy in the industry. The z-level profiling mode is only suitable for steep surfaces and ineffective for flat areas. The radial toolpath mode yields the highest quality but requires the longest processing time, appropriately increasing the path spacing can significantly improve the efficiency without substantially compromising quality. The surface flowline machining mode is only applicable to the single cambered surface. The offset contouring mode is the fastest but produces the lowest clarity in details. For the angular partition machining mode, processing quality and time can be optimized by setting an appropriate "inclination angle relative to the horizontal plane" parameter.