Abstract: For the problem of batch planning of 3D printing,a method based on work-piece layout was proposed.According to the features of 3D printing process,the objective of batch planning was set to minimize the total printing batches and the height difference of the printing parts in each batch.The printed parts were coded with integer numbers in sequence and the permutations of the sequence number formed the feasible solution set of the problem.In decoding stage,the printed parts were laid into the machine’s printing table orderly according to the sequence of solution.If the machine’s printing table was not with enough space to accommodate the printed parts further more,the next printing batch was arranged.This finally reached the printing batch scheme as well as the value of optimization objective function.For simplification,the minimum bounding rectangle of the horizontal projection shape of the printed part was adopted in part laying.Thus the problem of two-dimensional shape layout was simplified as the problem of rectangular packing.The lowest horizontal line algorithm and the Bottom-Left rule were applied in the rectangular packing.The lowest horizontal line segment of packed area contour was searched and updated repeatedly during part laying until the part could not be accommodated any more.The genetic algorithm was applied in searching the optimum solution.The proposed method of this paper was verified by example.

Key words: job scheduling, 3D printing, genetic algorithm, batch planning, layout