Topology Optimization of Plastic Parts for Injection Molding

Topology optimization is broadly recognized as a design approach to generate high-performance conceptual designs suitable for freeform fabrication, e.g., additive manufacturing. When other fabrication methods are considered, topology optimization must integrate manufacturing constraints. The integration of constraints for extrusion and casting has been addressed in the past by a few researcher groups. In this work, extrusion and casting constraints are revisited and extended to include plastic injection. The proposed method relies on the use of intersection planes and the definition of a parting line within the planes. The resulting topologies can be injected in a two-plate mold without the use of inserts. The implementation and results of the proposed approach are demonstrated in classic three-dimensional problems that include a cantilevered beam with different load conditions.

Robotic variable fabric formwork

Casting is one of the most widely used construction techniques. Complex geometries produced via computational design processes are not readily achievable through traditional rigid formwork and are subject to increased material waste. More suitable casting techniques are required to represent digital design output efficiently. This article presents a variable fabric formwork developed to work in conjunction with a 6-axis robotic arm for casting doubly curved panels based on hyperbolic paraboloid geometry. The variable formwork is designed to be extendable in length and width so that it can produce a wide range of outcomes within a single formwork. The interface established in the workflow allows the physical formwork and digital design to influence each other. The article concludes by discussing a verification method used to confirm the accuracy of the outcome. This variable fabric form-work reduces construction waste and is a more sustainable method for casting complex geometries. Highlights Robotic arm used to manipulate a bespoke mould for fabric formwork casting. Constraints of mould design used to inform robotic arm of its fabrication limits. Workflow allows the physical formwork and digital design to influence each other. Verification of result reveals future area of research.