By Olivia Cahoon
Part 2 of 2
Three-dimensional (3D) printing allows manufacturers to reduce costs, lower the risk of trial and error, and create opportunities for design innovation. Traditional 3D printing includes a melting or welding process with lasers or melted material. As 3D printing grows in popularity, new methods emerge to serve all types of industries. One such technology includes 3D printing with sand and metals.
ExOne for Additive Manufacturing
Founded in 2005 as a spinoff of Extrude Hone Corporation, ExOne Company is a global supplier and developer of precision nontraditional machining processes and automated systems. With headquarters in North Huntingdon, PA and nearly 100 full-time employees, the company also has locations domestically in MI, OH, and TX, and internationally in Germany, Italy, Japan, and Sweden.
The company started with a focus in 3D printing and currently supplies services, solutions, and systems for digital manufacturing including 3D printing in industrial-grade materials like metal and sand.
ExOne’s headquarters include a machine build center for metal 3D printers and a research and development (R+D) lab. It houses the Mid-Atlantic Produce Service Center for metal parts printing. The company serves aerospace, automotive, decorative, education, energy, foundries and pattern shops, heavy equipment, and R+D industries. ExOne offers applications like bath and kitchen fittings, castings, filtration, hand tool prototypes, prosthetics, and pumps.
Binder Jetting Technology
Digital part materialization for sand printing began in 1999 in Augsburg, Germany, where the first prototype 3D printer for sand casting molds and cores was created. In 2010, ExOne released the largest 3D sand printer, the S-Max industrial production 3D printer, designed for flexibility and efficiency.
In 1996, ExOne became the exclusive licensee of a 3D printing process developed at the Massachusetts Institute of Technology for metal parts and tooling. The manufacturer’s machines print on materials like bronze, ceramics, glass, silica sand, and stainless steel. Its applications range from heavy industrial equipment like impellers and toiling to consumer and decorative applications.
ExOne uses binder jetting technology for 3D printing in industrial-grade materials. It is an additive manufacturing process where a liquid binding agent is selectively deposited to join powder particles. Layers of material bond to form an object and the printhead drops binder into the powder. Another layer of powder is spread and binder is added again until the part develops through powder and binder layering.
Binder jetting prints materials like metals, sands, and ceramics. Sand requires no additional processing but other materials are usually cured and sintered. Binder jetting may print large objects like room-sized architectural structures.
Unlike other 3D printing methods that require a melting or welding process, binder jetting does not employ heat during building. Binder jetting requires no build plates, support structures, or tool paths. It allows fast design modifications and reprinting on CAD files without tooling changes. Multiple custom parts are built in a single print bed enabling for a short turnaround time. The technology also allows limitless patterns and part geometry.
ExOne offers manufacturing-quality materials to stand up to industrial use and easy integration into existing processes. Materials include ceramic beads, bonded tungsten, chromite, cobalt-chrome, IN alloy, iron, iron-chrome-aluminum, silica sand, soda lime glass, tungsten carbide, and zircon.
Its 3D prototyping printers include the S-Print and M-Flex prototype printing. The S-Print is intended for sand casting foundries and creating complex sand cores. It features a customizable platform and high productivity. The M-Flex is a metal printing 3D printer that offers flexibility from prototype to production. Its binder systems are aqueous, phenolic, and solvent and it builds from 30 to 60 seconds per layer.
Manufacturers turn to 3D printing because it saves costs, reduces lead time, and ensures high-quality materials. Speed 3D Mold Co., Ltd. recently approached ExOne for a bronze 50-inch diameter vertical pump impeller. The 20 year old vertical pump impeller was damaged from cracks and corrosion resulting from cavitation.
The customer had no available spares and needed to replace the 1,984 pound vertical pump impeller with an identical replacement.
ExOne used additive manufacturing and its binder jetting technology to print a complete sand mold package. The traditional method, casting using pattern-based mold, would have taken one year to complete and cost $80,000. Using ExOne’s sand printing method with silica sand and furan binder, the production time was six weeks and cost $50,000. The vertical pump impeller features a 0.22-millimeter layer thickness and was printed in less than one week.
ExOne believes its binder jetting technology ensures highly accurate blade orientation and minimizes post-casting machining time. The customer worked with a limited budget and was pleased with the finished vertical pump impeller.
Sand and Metal
Industries from aerospace to decorative and art seek 3D printing and industrial-grade additive manufacturing for cost effective and efficient prototypes and replacement materials. ExOne uses binder jetting technology with industrial materials to offer design freedom without tooling or build plates.
Jul2017, DPS Magazine