It appears we are well on the way to printer copper components which is good news. The application pathways are also potentially available for all other metals as well. I would like to see titanium printing as that has been problematic in terms of other forms of fabrication.
When 3D printing first happened, i was not that optimistic about its future impact. Now i know how we can produce a multilayered active skin for a UFO able to use super conducting fields to produce massive magnetic fields for space navigation. That problem only took a decade to properly scope.
I would like to see how annealing can be induced as well without tool use. Nice to see a way around brittleness at least..
These very same properties hindered its success as a feasible option for 3D printing. However, that has changed.
The most common technique for 3D printing copper is Powder Bed Fusion. It uses electronic beams to melt material powders and “glue” the material. When the temperature drops, the material consolidates together.
The most popular processes of Powder Bed Fusion are known as Selective Laser Sintering (SLS), for plastics, and Selective Laser Melting (SLM), for metals.
Despite SLM being an excellent printing process for many metals, there was a particular challenge when it came to 3D printing with copper.
The conductivity properties of the material cause the heat of the electronic beams to be reflected instead of absorbed.
Another reoccurring problem was the fact that the printed part would crack when the temperature would drop too fast and/or too low.
Towards a solution: green laser and pre-heating
Their solution consisted of switching the infrared laser from an SLM machine with a green laser. It sounds simple, right?
It is a bit more complex than that. A quick search on Wikipedia teaches us that laser is an acronym for Light Amplification by Stimulated Emission of Radiation. In short, lasers are light sources characterized by their wavelength in a vacuum. Each type of laser projects a concentrated beam that is amplified using stimulated radiation.
The light from this green laser for SLM printers developed by the German institute is better absorbed by copper which facilitates the melting of the material.
But the issue of cracking due to temperature drops was still there. The solution was to pre-heat the material before starting the printing process, which is sufficient to avoid a huge temperature drop.
This technique comes as the first real alternative for copper 3D printing, presenting a fantastic opportunity for manufacturers.
Machine manufacturer TRUMPF has applied these technologies in its new machine, the TruPrint 5000.
The machine uses TruPrint Laser Metal Fusion (LMF), a green laser, and preheats to material to 500 °C.
The TruPrint 5000 was demonstrated at the Formnext, 3D print fair in Frankfurt in November 2018.
The machine also prints with other precious metals – not only copper.
Layer of powdered Copper is exposed to a green laser during the SLM 3D printing process. Source: Fraunhofer ILT
As pointed out: copper has interesting thermal properties and together with the advantages of AM, particularly the design freedom, makes the additive manufacturing process beneficial for many thermal applications.
To anticipate the demand for copper in AM, different companies are developing special copper and copper alloy powders for the 3D printing market, notably Heraeus, Oerlikon and Stratasys.
Heraeus presented its highly conductive 3D-printed copper components at At the Formnext 2018.
It appears that we are on the way to
The material has been tested with aerospace companies.
- electrical wiring (copper is a conductor of heat and electricity,
- building material for roofing, plumbing, decorative elements and sculptures (for ex the Statue of Liberty is made from copper). The copper oxidizes and becomes a light green color.
- constituent of various metal alloys, such as bronze (a copper-tin alloy) and brass (a copper-zinc alloy) and Sterling silver (silver-copper alloy)
- machinery and motors
- marine applications: copper is biostatic, bacteria or other live forms will not grow on it. It was used in shipping to prevent growth on hulls.
- sinks, faucets, doorknobs, handrails etc. Because copper is biostatic it is used (in various alloys) in appliances that are handled by many people, to avoid spreading bacteria.