Area clearance toolpath generated area clearance mainly in order to remove a lot of material, generally with one layer at a time of flat milling cutter cut, layered cut.Layered cutting thickness is determined by the tool parameters and surface shape.Rough surfaces as well as in certain gaps (cutting tolerances) envelope within subdivision surfaces, and facilitates quick calculations. Best way is to use an intermediate not precise mesh as a rough surface, but the coarse mesh may not be able to meet the conditions but cut, hence the need to shift to the closest but it cut the processing conditions of the mesh, called cover surface.
Covering surfaces shown cover surface is an example of the basic concepts in a two-dimensional plane. Under surface node to the node as shown in position to solve the problem. The position of the new node can be offset by cutting within tolerance limits of their position to determine, so that you can build an envelope surfacelimit surface coverage. However, this approach is not easy to achieve in a three dimensional space, because even though all controlled nodes above the surface, limiting surfaces may partly also beyond the surface, as shown in. The excess throughthe grid of local check it out, and then judge whether the vertex falls on top of thetriangle.
Z-map model for rough surfaces for roughing surfaces covered surface, you can create a Z-map model. To sample data, sampling interval can be carried out using the following formula:), 2/min (r-η γ = η roughing cutting tolerances, and r is the RADIUS. Roughing cutter position computing layer when cutting, roughing needs tocalculate the position of each tool. Using the create overlay surface Z-map model,for each x (or y) constant grid of lines, an ambiguous line can be defined by z-map model. And then in the vertical direction (z-direction) cut one layer at a time, findthe intersection of layers with multi-line. These nodes are defined as CC (NC contact), then the offset calculation tool radius r CL (Cutter location), by connecting these CL points, you can get a tool path. By repeatedly using (sampling interval), can get all facets of the area clearance toolpath.
Process interference check and correct at the time of processing, the selected toolor could not be processed so as to interfere with. Interference check and avoidance are very important. In this study, the coverage limit surface is a surface envelope,we are mainly dealing with processing of interference, especially within the concave area, when the cutter is too large to process. In order to inspect the uncut area,you need to compute the curvature of each CC. The radius of curvature can be calculated according to the G.Taubin method. If you CC the triangle within a trianglemesh, first calculate the curvature radius of the triangle vertices of subdivision surfaces, and CC the Barycentric coordinates of the point of the triangle, calculation atup-CC points of difference between the radius of curvature.
Interference checking, first compare the cutter contact point of curvature RADIUS and curvature radius of the tool database tool, and then select the tools all contactpoints is less than the radius of curvature of the RADIUS tool to meet the processing does not interfere.
If the database does not contain tools meet the conditions, an increase in a small radius of the tool the tool path calculation. Simulation results and conclusion based on the above model and tool-path generation method of Z-map, based on the VC++6.0 tool was developed based on OpenGL subdivision surface machining simulation program. The process iteration with subdivision surfaces generation, meshoffset surface generation, tool path generation and machining simulation capabilities. Build processing simulation results as shown in. Simulation results of the simulation results show that the proposed Loop subdivision surface and tool path generation of three axes NC rough machining possible.
