I see a few challenges. First is equipment capable of doing the manufacturing. Most are expensive, and those that are sub 100K have very small build chambers and thus can only do very small parts. This can be okay for small jewellery, but then the second problem comes up materials. In order to develop a new material on a machine, it takes a lot of time and effort to get it right. When working with precious metals, the raw material costs are prohibitive to try and work with them. Even if cost isn't a problem, the powder needs to have the right characteristics in order to properly flow within the machine, which is difficult to do for high-cost raw materials. For instance, one person spent 3+ years of their PhD to process Gold, and that was a challenge. https://link.springer.com/article/10.1007%2FBF03214976?LI=true Gold and silver are difficult to work with lasers due to high reflectivity and high thermal conductivity, which both prevent the material from melting and creating solid structures.

First is equipment capable of doing the manufacturing. Most are expensive, and those that are sub 100K have very small build chambers and thus can only do very small parts. This can be okay for small jewellery, but then the second problem comes up materials. In order to develop a new material on a machine, it takes a lot of time and effort to get it right. When working with precious metals, the raw material costs are prohibitive to try and work with them. Even if cost isn't a problem, the powder needs to have the right characteristics in order to properly flow within the machine, which is difficult to do for high-cost raw materials. For instance, one person spent 3+ years of their PhD to process Gold, and that was a challenge. https://link.springer.com/article/10.1007%2FBF03214976?LI=true Gold and silver are difficult to work with lasers due to high reflectivity and high thermal conductivity, which both prevent the material from melting and creating solid structures.

In order to develop a new material on a machine, it takes a lot of time and effort to get it right. When working with precious metals, the raw material costs are prohibitive to try and work with them. Even if cost isn't a problem, the powder needs to have the right characteristics in order to properly flow within the machine, which is difficult to do for high-cost raw materials. For instance, one person spent 3+ years of their PhD to process Gold, and that was a challenge. https://link.springer.com/article/10.1007%2FBF03214976?LI=true Gold and silver are difficult to work with lasers due to high reflectivity and high thermal conductivity, which both prevent the material from melting and creating solid structures.

Even if you are able to process a material for jewellery, the surface finish is very rough and needs a lot of post processing in order to make it smooth and shiny. This third problem requires a lot of hand work which may discourage direct jewllery manufacturing.

But there are many looking at additive manufacturing for jewlery (http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1727554), but more with materials that are cheaper and easier to work with, and then plating and post polishing them with industrial methods to get the surface finish that is desirable from jewellery. 

I think that there are al leaast two problems: one of them is the value of a SLS equipment, and the other is that you need powder of precious metals.

What can you do if you want to 3D print metal at home? As extremely high temperatures are needed for metal 3D printing, you cannot use a regular FDM 3D printer for it.

Simply put: There’s no way you’ll gonna 3D print pure metal at home this decade. And you probably won’t have a dedicated metal 3D printer standing in your home until 2020. But in some years, as nanotechnology evolves, we might to see a substantial growth in new applications. Like conductive 3D printable silver that can be ink jetted using a system very similar to the 2D graphic printer, you have at home. Even mixing different materials, like plastics and metals into the same object, is going to be possible.

These are Materials for Home Metal 3D Printing

Even if you can’t 3D print metal objects at home, you can still resort to plastic filament with added metal powders. ColorFabb, ProtoPasta or TreeD Filaments offer interesting composite metal-PLA filaments. These are filaments that contain a significant percentage of metal powders but provide enough plastic to be printed at low temperature (200 to 300 degree Celsius) with just about any 3D printer. At the same time, they contain enough metal to look, feel and even weight of a metallic object. The iron-based filaments even form rust in certain conditions.

But you can go even further. Usually, metal 3D printing filament has 50 percent metal powder added. Dutch 3D printing filament company Formfutura claims they have ramped the ratio up to 85 percent metal powder and 15 percent PLA. The metal 3D printing filaments are called MetalFil Ancient Bronze and Metalfil Classic Copper. You can even print it at “moderate” temperatures of 190 to 200 degree Celsius.

Hi Amira,

do you have any numbers on the statement "has not been as popular"? How big is the market in total (money and pieces)? Do you exclude 3D printing cast-technologies for jewellery in you research? If so, why? In my opinion jewellery is a broad term and your question would benefit from further clarification and boundaries (time, location, etc.).

Cheers

 Felix

I see a few challenges. First is equipment capable of doing the manufacturing. Most are expensive, and those that are sub 100K have very small build chambers and thus can only do very small parts. This can be okay for small jewellery, but then the second problem comes up materials. In order to develop a new material on a machine, it takes a lot of time and effort to get it right. When working with precious metals, the raw material costs are prohibitive to try and work with them. Even if cost isn't a problem, the powder needs to have the right characteristics in order to properly flow within the machine, which is difficult to do for high-cost raw materials. For instance, one person spent 3+ years of their PhD to process Gold, and that was a challenge. https://link.springer.com/article/10.1007%2FBF03214976?LI=true Gold and silver are difficult to work with lasers due to high reflectivity and high thermal conductivity, which both prevent the material from melting and creating solid structures.

First is equipment capable of doing the manufacturing. Most are expensive, and those that are sub 100K have very small build chambers and thus can only do very small parts. This can be okay for small jewellery, but then the second problem comes up materials. In order to develop a new material on a machine, it takes a lot of time and effort to get it right. When working with precious metals, the raw material costs are prohibitive to try and work with them. Even if cost isn't a problem, the powder needs to have the right characteristics in order to properly flow within the machine, which is difficult to do for high-cost raw materials. For instance, one person spent 3+ years of their PhD to process Gold, and that was a challenge. https://link.springer.com/article/10.1007%2FBF03214976?LI=true Gold and silver are difficult to work with lasers due to high reflectivity and high thermal conductivity, which both prevent the material from melting and creating solid structures.

In order to develop a new material on a machine, it takes a lot of time and effort to get it right. When working with precious metals, the raw material costs are prohibitive to try and work with them. Even if cost isn't a problem, the powder needs to have the right characteristics in order to properly flow within the machine, which is difficult to do for high-cost raw materials. For instance, one person spent 3+ years of their PhD to process Gold, and that was a challenge. https://link.springer.com/article/10.1007%2FBF03214976?LI=true Gold and silver are difficult to work with lasers due to high reflectivity and high thermal conductivity, which both prevent the material from melting and creating solid structures.

Even if you are able to process a material for jewellery, the surface finish is very rough and needs a lot of post processing in order to make it smooth and shiny. This third problem requires a lot of hand work which may discourage direct jewllery manufacturing.

But there are many looking at additive manufacturing for jewlery (http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1727554), but more with materials that are cheaper and easier to work with, and then plating and post polishing them with industrial methods to get the surface finish that is desirable from jewellery. 

Hi Amira! How U doing?!

"(...) One of my aims is to find out why direct 3d printing in particular in the jewellery industry has not been as popular (...)"

As Felix said, have U measured this niche market? R U sure about it?

One of the answer is: cost and price. Of equipments, materials, maintenance and relative to conventional manufacturing processes (investment casting). There are a few additive manufacturing equipments that use wax to produce a model or prototype, but after this step, they are used in a conventional way to turn it into the final product.

"(...) and any challenges that exist (...)"

To produce these materials (how they going to be, a powder, a filament, a liquid, a blend, a mixture... and its cost) and to process them in a suitable way that the result is better or at least the same as conventional ways (surface finish, easiness of production...). The final cost also must be less or equal (mass production)...

What are the main challenges of direct 3D printing with precious metals?

The price of the material. As mentioned by Casidy, to develop these materials U need time. To process it properly U will need even more time and probably will waste a lot of material, and talking about precious metals, U know what this mean. Metals and hard to process materials are usually processed via laser sintering/melting technologies, which means that the material must be in a powdered form (Yea! Can be inna liquid form, but only for polymers!).

Do a little research on how to do a powder from any material and U will start to have a glimpse on the subject (U can start checking the books:

Powder Metallurgy Science by Randall M. German, 1994

https://www.amazon.com/Powder-Metallurgy-Science-Randall-German/dp/1878954423

Powder Metallurgy: Science, Technology, and Materials by Anish Upadhyaya and G.S. Upadhyaya, 2011

https://www.crcpress.com/Powder-Metallurgy-Science-Technology-and-Materials/Upadhyaya-Upadhyaya/p/book/9781439857465

The processability of this material also presents as a concern (laser absorptivity, reflectivity, thermal conductivity, balling (specially for metallic material) and all the laser-material interactions!)

Despite this there are a few players in the market that have additive manufacturing equipments capable of procesing metal materials directly, as also cited by Cassidy, with the SLM or DMLS technology (EOS GmbH)

https://www.eos.info/industries_markets/lifestyle_products/jewellery_watches

Another manufacturer is Concept Laser, which gives name to its process with the term "LaserCUSING®," coined from the C in Concept Laser and the word FUSING.

https://www.concept-laser.de/en/industry/jewellery.html

https://www.concept-laser.de/en/products/materials.html

(check 'precious metals)

Hope I could help!

ATB!

Cheers!

Dear Amira,

I agree that the effort and cost required to fine tune the process of Laser Beam Melting (equivalent to the trademarks SLM, DMLS, LaserCusing and others) to any new alloy are a high threshold, not only in the field of jewelry, but also in any other.

Producing metal powder via gas atomization is not a very common capability, either. Especially if small batches of a few kg are necessary to keep the total invest manageable, this is a challenge in itself.

Just in case you have not already checked it -  for a market survey I recommend Wohlers Report https://wohlersassociates.com/

Please consider the fact, that not all users of Additive Manufacturing technology communicate freely about how they manufacture products but prefer to keep their competitive advantages hidden.

Apart from EOS (partnering with http://www.cooksongold-emanufacturing.com/) and Concept Laser already mentioned above, do not miss ReaLizer (partnering with http://www.progol3d.com/ ) and Sisma ( http://www.sisma.com/eng/jewellery/news/new-products/my-sint-additive-manufacturing.php https://www.youtube.com/watch?v=xmUMFW6r3V0) as manufacturers of Additive Manufacturing systems dedicated to direct laser processing of precious metal powders.

From a physical point of view, LBM requires a stable melt pool. To achieve this, a quasi-stationary equlibrium must be reached balancing heat input caused by a Laser beam and heat output through radiation, convection and conduction through already solidified layers below the melt pool. This is very similar to Laser Welding, but on different scales of length and time. With precious metals and their high conductivity and low absorptivity you need pretty high intensity of the laser, meaning power per irradiated surface area. The machines of the above mentioned suppliers only feature low laser powers of some 100 W, but these are focussed down to as small as 20 µm spot diameter, providing considerable intensity.

Absorptivity and conductivity strongly depend on alloy composition. In general, pure metals like e. g. pure gold have the highest thermal conductivities. Even very small additions of other elements can reduce thermal conductivity more than proportionally.

Another requirement in LBM is that the material solidifies forming as little defects (such as cracks or pores) as possible. Otherwise, it will be hard to create a shiny jewelry surface by polishing. Cracking and pore formation depend both on the powder material and the processing conditions. Typically, alloys that have succeeded in casting are promising candidates for LBM, too. But experimental proof is inevitable.

Here is a publication about silver LBM: http://www.rtejournal.de/ausgabe9/3363

Nice examples of lost wax casting of precious metals with 3D-printed lost models can be found here: https://www.imaginarium.io/case-studies

An established provider of wax printers is e. g. solidscape https://www.solid-scape.com/

Hope this is helpful for your research.

Regards, Michael

Dear Amira,

I worked on selective electron beam melting as a PhD student and now work at Heraeus Additive Manufacturing GmbH. The backbone of Heraeus are precious metals and we are working on various Gold / Platinum / Rhodium / Iridium / Silver alloys predominantely in selective beam melting processes.

As others have pointed out, the main challenge actually is non-suitability of most commonly available printing machines. Whereas the off-the-shelf Laser machines operate at wavelengths, in which most precious metals reflect, coupled with high conduction losses, the available electron beam melting machines have a too large building chamber for precious metals. The Arcam systems typically need approx 50 kg of powder to operate. Building plate reductions as retrofits often lead to instability of powder application.

Sintering routes are viable in general, but not as prominently followed as the selective beam melting routes in general.

If you need further info, or are interested in powders, etc. you can contact me at [email protected]

Best,

Andreas

Dear Amira,

One could imagine a laser based drop on demand process, which is capable of printing single particles of precious metals. Using that process, one can get rid of overspray, since one deposits droplets only at the desired position.

A possible approach was published here:

http://www.jlps.gr.jp/jlmn/upload/2633dd44a74cc80a417d9c07831e60ca.pdf

I used CuSn braze preforms, which I deposited on Ag-electrodes, however Au or other precious metals seem feasible as well. I am in contact with a company, which is able to provide spherical particles of precious metals by applying a punching and a subsequent remelting process, resulting in spherical particles with low mass/volume deviations. If you need assistance feel free to contact me.

I hope this was helpful.

Kind regards

Stefan