How can you 3D print metal at lower temperatures than melting metal? This video teaches you how to understand the technologies behind filament-like metal 3D printing.
- [Woman] Creating a metal 3D printed part is often a multi-step process, only one step of which involves 3D printing. In this video we'll look at the overall process of 3D printing with a filament or other mix of plastic and metal. There are many variations depending on the materials and use, and we start with a generic option here. The process starts with metal powder embedded in plastic, usually in the form or rods or filament that can be fed into an extruder. Typically the percentage of metal is stated as a fraction by weight, around 90% or so; however, since metal is many times denser than plastic, the percentage of metal by volume is a lot lower. For example, steel has about eight times the density of PLA plastic, so a steel-PLA mix that is 90/10 by mass, would be about 52% metal by volume. - [Man] Printers designed for this process my use cartridges specially designed to feed rods one after another into the extruder. These rod-based systems avoid the brittleness issues that can arise from using large quantities of metal filler in a narrow filament. Extruders designed to push rods maybe also be able to exert more force than those gripping filament, at the cost of greater complexity. Filament, on the other hand, can be printed on an ordinary consumer-level 3D printer, at least in principle. The printer will need an appropriate build surface, and needs to be able to handle the temperatures required for the base plastic. Metal-filled filament can be very brittle. Some filament manufacturers recommend an aftermarket warmer to heat up the filament a little to make it more pliable before it goes into the 3D printer. The filament from the Virtual Foundry, shown here, was not heated before doing this demonstration. Most printers come with nozzles made of brass because it has good thermal properties. And the fact that it's a relatively soft metal makes it easier to machine; however, the metal particles in these filaments are much harder than the molten plastic these nozzles are designed for. It can abrade them fairly rapidly. Special nozzles made of hardened steel or tipped with ruby are available for many machines as aftermarket upgrades. - [Woman] Bound metal printing can use metal powder in form factors including filament and rods. There are integrated systems and filaments that can be used on low-cost printers. The details of how your part might go through the stages of creating a print will determine the most economical solution for your parts.
- Process introduction
- Materials considerations
- Debinding and sintering
- Resolution, shrinkage, and isotropy
- Post-sintering treatment
- Outsourcing vs. in-house manufacturing
- Metal 3D printing alternatives