Innovative Mechanical Technologies Vacuum Casting & Metal Part Casting Gustaw Koenig Paweł Roczniak
Overview Additive Manufacturing
Metal Part Casting
Definitions Additive Manufacturing - process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies. Synonyms: additive fabrication, additive processes, additive techniques, additive layer manufacturing, layer manufacturing, and freeform fabrication. Rapid Tooling - the use of additive manufacturing to make tools or tooling quickly, either directly, by making parts that serve as the actual tools or tooling components, such as mold inserts, or indirectly, by producing patterns that are, in turn, used in a secondary process to produce the actual tools. Standard Terminology for Additive Manufacturing Technologies International Committee F42 for Additive Manufacturing Technologies ASTM
Rapid Tooling Process Types - Methods Rapid Tooling
Tool is directly build in additive manufacturing process.
Tool is made based on master model build in additive manufacturing process.
Vacuum Casting Process and Materials Vacuum Casting Generally refers to casting two part polymer (resin) into mold under vacuum. Casting material - two part polymer (synthetic resin) that can closely resemble mechanical properties of typical plastic e.g. ABS, PS, PMMA etc. Types: • polyurethane resins • epoxy resins • acrylic resins Basic Parameters: • Young's modulus [Mpa], • Hardness [Shore A-D], • Viscosity [mPa.s], • Pot life [min].
Mold material - two part Silicone Rubber (synthetic rubber) Polymerization mechanism: • Addition reaction • Condensation reaction Basic Parameters: • Hardness [Shore A], • Tear strength [kN/m], • Elongation at break [%], • Tensile strength [Mpa], • Pot life [min].
Vacuum Casting (Indirect Method) 1. Forming a mold cavity based on master model shape by pouring two component Silicone Rubber into flask. 2. Degasing Silicone Rubber by applying vacuum to the mold. 3. Mold curing in oven at around 70°C – usually overnight. 4. Creating a parting line by cutting open the mold and removing the master. 5. Putting back segments together and sealing the mold. 6. Preparing casting material – weighting and adding pigment if necessary. 7. Mixing components under vacuum (process can be automated by PLC). 8. Pouring mixed components into mold cavity under vacuum (process can be automated by PLC). 9. Curing material in oven 70°C (procedure depends on material type). 10. Opening the mold and removing casted part. 11. Finishing – trimming excess material and polishing as required.
Prepare a master model and establish the parting line with tape.
Remove the master mode
Make a casting frame in ABS or chip board.
The automated casting cycle fills the mold under vacuum.
De-gas the Silicone Rubber and pour around the model and leave to cure.
Produce multiples of exact prototypes in as many as 30 different materials - color matched or transparent, in injection molding quality.
Additive Manufacturing Technologies used for Vacuum Casting Master models can come from a range of sources, the most common being: • Stereolithography • Multi Jet Modeling • Digital Light Processing Printers There are also many other sources of master models as the range of CAD driven 3D printers is still increasing. IMPORTANT: The quality of the master model dictates part quality.
Typical applications • • • •
High quality prototypes Product design verification Small batch production Functional components made from materials not available for additive manufacturing process e.g. nylon particularly good for living hinges and high strength • Automotive ‘hot test’ and specialist manufacture • High quality wax masters for investment casting • Production of EP tooling resin molds
Metal Part Casting is a new and complete package process for producing quick metal prototypes and mould inserts in as little as one day in materials such as zinc, aluminium, bronze, brass and copper when using "burn out" models in wax, polystyrene (SLS) or Quick Cast. Or, three days when using other types of model from which moulds for vacuum casting of waxes need to be made....