Abstract: Disclosed is an apparatus for horizontally aligning a bed of a three-dimensional printer, the apparatus enhancing quality of a 3D object produced on the bed, by tilting the bed on two axes so as to horizontally align the bed before operating the three-dimensional printer. The three-dimensional printer produces the 3D object by depositing materials on the bed with an extrusion head, the apparatus including a tilting unit tilting the bed on two axes to horizontally align the bed, when the bed is not horizontal.

Abstract: A method for determining defect causing equipment in a manufacturing process includes collecting equipment sequence data and processing result data of a plurality of products, calculating defect contribution scores for a plurality of equipment based on the collected data, and applying a modified association rule to the equipment based on the calculated contributions scores. The modified association rule to generate rules reflecting a cumulative effect of an equipment sequence and equipment contributing to a defect of at least some of the products. The method also includes calculating a defect-introducing index based on the calculated contribution scores and the modified association rule, and identifying at least one of the plurality of equipment as causing the defect of the products based on the defect-introducing index.