The Selective Laser sintering process (SLS) allows the manufacturing of complex thermoplastic parts without the need for an expensive mold. However, the available material portfolio is very narrow and yet does not offer a silicone rubber type material, which can be used for medical applications. Thus, in this approach the applicability of SLS vacuum die casts for the manufacturing of patient individualized flexible silicone implants shall be analyzed. The heart insufficiency is medically a complex desease, which usually requires eventually heart transplantation surgery. However, an internal flexible heart supporting system could support and cure the organ significantly. This requires patient individualized geometries, flexible structures and reinforcements such that compression forces only affect the heart but not the surrounding organs. Therefore, basic studies on the molding and demolding of silicon specimens using SLS vacuum die casts shall be investigated as well as the possibility for including flexible reinforcement structures. First, simplified mechanical tests show the feasibility of the manufacturing process as well as optimization potential using patient individualized geometries. First functional silicon heart supporting structures are successfully manufactured and can be used for medical tests.