Raft technique in three-dimensional printing

Abstract

A raft to support a three-dimensional object on a build platform of a three-dimensional printer can be fabricated with a controlled adhesion pattern to improve overall raft performance. For improved raft-to-build platform adhesion, an exterior portion around the perimeter of the raft may be fabricated with greater adhesion (per unit of surface area covered by the exterior portion) than an interior portion. This can be accomplished by varying the volume of build material, varying the printing height, or using different patterns of build material. At the same time, adhesion of the raft to a printed object built thereon can be controlled with a number of techniques such as using specific build patterns for the top layer of the raft or varying printing heights (e.g., z-axis position) between the top of the raft and the bottom of the object.