Dynamic slicing method for additive manufacturing forming with variable forming direction

An electron beam manufacturing (EBM) variable-direction formation dynamic slicing method in cooperation with a numerical control system, comprising:

• step S1:
• loading an STL file, creating a vertex array object (VAO), turning on a template buffer, adjusting a projection matrix to a slice height in rendering of a three-dimensional (3D) model, traversing all pixels in a field of view sequentially by determining an intersection between a viewpoint and a voxel using a reverse ray tracing algorithm, reading image data from pixels at a set height, and outputting a binary image of a two-dimensional cross-section;
• step S2:
• obtaining, by means of two-dimensional contour extraction, data of a contour line from the binary image obtained in the step S1, outputting coordinates of a closed contour, and connecting all adjacent coordinates into a straight line in such a manner that respective straight lines are connected end to end to form a closed curve;
• and
• step S3:
• when a triangle tolerance is 1, dividing contour data into a straight line part and a curve part by taking a starting point of small straight lines with an angle of 140° therebetween as a dividing point, removing adjacent points, repeated points and internal points of a same straight line, and performing segmentation fitting on curve parts of the slice data by using a NURBS curve, and then performing dynamic slicing through the numerical control system,
• wherein after the fitting in the step S3 is completed, an angle of a worktable of the numerical control system is adjusted based on a formation direction of each feature of the model;
• a first motor, a third motor and a fifth motor of the numerical control system are linked to complete spatial curve formation;
• the first motor moves by rotating and a second motor of the numerical control system moves in a straight line to work in cooperation with each other, to form a straight line, a full circle, an arc and an Archimedes spiral in the plane, for use in contour approximation fitting, island profile filling, full circle formation, straight line formation, arc formation during curve formation;
• and a quick response is made to a setting of dry elongation, a distance between a formation plane and an electron gun is dynamically adjusted, the slicing is performed.