Case Study: Heavy Bikes achieves single-piece, weld-free aluminum bike frames with ExOne binder jetting

Single-Piece Bike Frames Cast in Aluminum with 3D Printed Molds

Heavy Bikes set out to produce custom, single-piece cast aluminum bike frames that eliminate welds and the common defects of traditional casting—porosity, shrinkage and long lead times—while enabling rapid design iteration. To do this the team used ExOne binder-jetting technology (an ExOne S-Max® system printing silica sand molds and cores) so they could cost‑effectively explore complex thin‑walled designs and avoid expensive hard tooling.

Using ExOne’s S-Max printed sand molds (produced by Liberty Pattern) together with Foundry Casting Systems’ Pascal pressurized solidification, Heavy Bikes cast A356 frames that are higher density, far less porous and mechanically stronger than typical sandcastings. ExOne’s digital tooling enabled near‑perfect molds (98.6% first‑shot accuracy), quick iterations (eight design updates since 2022 and a one‑week reprint after a test failure), ISO‑compliant finished bikes, and measurable gains such as about 1.1 lb (486 g) mass reduction on the latest generation.

Heavy Bikes

Charlie Murray

Co-Founder