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CAD/CAM Library

Note: For a full list of available articles on CAD/CAM (including those available in PDF format only), go to the MJSA Bookstore. To return to the online article search, click here.

Calibrated Clay, Part 2  Integrating ZBrush into CAD jewelry design. By Darla Alvarez, GIA jewelry design & technology instructor

CNC Milling vs. 3-D Printing Which is the right choice for your design? By Shawna Kulpa

A Cross-Sectional Critique Applying clipping planes to model manufacturability. By Darla Alvarez

Curves with Intentions The benefits of using well-considered curves in CAD/CAM. By Charlie Herner

Design Simplified How jeweler Randy Erickson used CAD/CAM to create an award-winning ametrine pendant. By Peggy Jo Donahue

Digital Dive  Tips for taking the plunge into CAD. By Shawna Kulpa

The Future of CAD? A look ahead to the use of generative design technology.

Get in Control Using control points to refine CAD designs. By Darla Alvarez

Getting into Print A primer on 3-D printing technology. By Shawna Kulpa

The Fix Is In Using CAD repair programs to save unprintable files. By John Shanahan

Hand in Hand, Part 1 Old world craftsmanship meets technology in this engraved man’s band. By Charlie Herner and Jason Marchiafava

Leaving Your Mark Custom jeweler Tom Linenberger shares his "wabi sabi" approach to CAD design. By Tom Linenberger

A Little Something Extra Tips for building additional setting material into your CAD files. By Charlie Herner

Melee Matters Looking beyond standard melee sizes for better layouts. By Charlie Herner

Old Vs. New Is it better to use a traditional approach or CAD/CAM technology to create a setting for a uniquely shaped stone? Jeweler Lee Krombholz set out to find the answer.

The Power of Powder

Overcoming obstacles in 3-D metal printing

By Shawna Kulpa

Three-dimensional metal printing offers users the ability to take CAD files and print them directly in metal—no resin to cure or burn out, no casting necessary. It’s been around for nearly 30 years and has gained traction in various industries, including aerospace, medical, and automotive. It first entered the jewelry industry around 2012—and has been slow to make any headway since then. “The industry has been slow to adopt the technology,” admits David Fletcher, head of special products at Cooksongold, which both sells 3-D metal printers and operates a printing bureau in Birmingham, England.

Some of that resistance stems from obstacles such as poor surface finishes and high price tags. Fletcher also believes it comes from a misunderstanding that 3-D metal printing is a replacement for hand fabrication or casting.

But that may be starting to change.

Fletcher notes that starting in the fourth quarter of 2018, they’ve seen a distinct change in attitude within the industry, with more clients willing to adopt the technology. “Since the launch of the Cooksongold 3-D bureau service in September, we have seen…the number of clients using the service increase by 200 percent. The majority of the production has been in sterling silver, 950 platinum, and 18k rose gold,” he says.

He believes this is a result of people understanding that 3-D metal printing isn’t designed as a replacement for more traditional methods, but rather as another option that gives companies the ability to create designs they couldn’t achieve otherwise.

This shift in interest comes at an opportune time, as some advancements in the technology have been made to help address surface quality and the high cost of entry. Not every obstacle has been overcome, but enough progress has been made to ask: Is the time for “powder power” close at hand?

The Basics of 3-D Metal Printing

Direct printing of metal using a laser is known as DMLS (Direct Metal Laser Sintering) and SLM (Selective Laser Melting), among other names. It works like other 3-D printing technologies in that a CAD file is divided into a series of 2-D parallel surfaces. A metal printer spreads a thin layer of metal powder, and a laser scans the portion dictated by the 2-D CAD layer, which results in the melting of that portion of powder into a dense solid. This process then repeats—a new layer of powder is spread out, the laser makes another pass—and continues as the piece slowly builds, layer by layer. Once the build cycle is complete, the finished metal part can be removed from the machine and sent off for finishing. It sounds like a jeweler’s dream—no waiting for wax or resin to burn out, no casting to worry about. But there are a number of obstacles that have prevented this technology from widespread use.

First, the surface finish of the models produced is not ideal, as the finish of the metal pieces tends to be pretty rough. And because these machines excel at creating pieces with interesting and unusual geometries, finishing those pieces could be a real challenge.

Next, there’s the cost of the printer and metal powder. Early on, some printers cost upward of $250,000, making it cost prohibitive for most jewelers. Even if you were able to swing the cost of the machine, the cost of the metal powder needed to fill the machine’s sizable build chamber would likely break the bank. Although the price of printers has been coming down, it’s still in the six figures—which may leave you wondering why ex-actly this technology is something you should consider, especially if you’ve been managing just fine with hand fabrication and casting.

“Unfortunately, direct metal printing doesn’t solve a specific problem for our industry like the laser welder did,” admits Steve Adler of A3DM Technologies, a 3-D research and development company based in Vermont. “On the other hand, a thoughtful designer can produce styles by this method that cannot be made by traditional methods, which can certainly set one apart from the competition.”

Fletcher likens the technology to “a bit of a chicken-and-egg scenario. [Jewelers] need to design for the technology to get the most out of it.”

He notes that when Cooksongold first started its service bureau offering metal printing, it received hundreds of files from clients. But most of them were suitable for casting, which defeated the whole purpose.

“We’re not trying to compete with casting,” he says. “We’re making things you couldn’t make before.”

One of those things is hollow items.

“Closed, hollow objects with wide continuous surfaces are probably the most suitable design for [this technology],” says Luigi Benetti of Progold S.p.A., a direct-to-metal service bureau in Trissino, Italy. “Parts can have a larger volume but a low weight due to very thin [but dense] walls.”

Joe Strauss, president of Queensbury, New York–based HJE Co. Inc., a manufacturer of metal powder atomizers, agrees. “One of the things that’s attractive is the fact that you can do hollow stuff. You pay for jewelry by the ounce and you buy it by the size. Everyone wants big and flashy. Making pieces hollow, you reduce the cost.

Henrich & Denzel Bracelet and Ring

Greater availability of platinum powder has allowed jewelers to discover the possibilities of printing thin, lightweight yet large and dense jewelry designs in platinum.

“The most successful prints are those that take advantage of what the technology offers—thin, lightweight, customized products,” he adds. He notes that using the technology to create hollow watch cases is of great interest to premium watch manufacturers. “They can offer large, bold, precious metal watches that don’t cost a fortune or weigh too much to wear comfortably.”

The technology is also great for working with platinum.

“Platinum ruthenium is the best material to work with inside the technology,” says Fletcher. “It yields the best surface quality (compared to casting), there’s no shrinkage, the density is incredible, and it has 0.1 percent porosity, which is incredible for a 3-D printed part.”

And, as Strauss succinctly puts it, “platinum is a pain to cast.” (It’s also, he adds, “a big growth area”: Scarce until about a year ago, platinum powder is now being atomized by several companies, providing a more plentiful supply.)

But beyond unique geometries and ease with platinum, it still comes back to design and whether or not something is ideally suited for this type of production.

“It wasn’t our intention in the beginning, but it was clear that we needed to educate on how to design for the process,” says Fletcher. To help companies understand how they can best design to take advantage of this technology, Cooksongold has a design consultant that can go in to a customer’s shop to spend time with the design team. The consultant will later return to the shop to check in with the team to review their work and offer any additional pointers. The company is also going to start offering two-day jewelry design courses that will teach jewelers how to design for the technology.

It’s All in the Finish

The technology definitely has benefits (assuming the designs are right for it). However, the drawbacks mentioned earlier have prevented its acceptance by the jewelry industry. The 3-D metal printing companies have been trying to overcome those obstacles—and in many cases, they’re making progress.
One of the big concerns for putting this technology to use in the jewelry industry has been the poor surface finish on the resulting models. The poor finish is a direct result of the printing process.

To understand why, consider that in 3-D printing, several factors contribute to the finish of printed metal parts.

• The first factor is the layer thickness that’s used to build the model. Just as in 3-D resin printers, the model is built as a series of layers, and the visible marks of demarcation between the layers create a “staircase effect.” How badly the “stairs” mar the surface will depend on the thickness defined in the CAD file for each layer.

“The thinner the layer, the smaller the stairs, and the better the surface finish,” says Strauss.

The size of the metal powder particles being used also contributes to the layer thickness. “In the past, many of the 3-D printers could not handle very fine powder,” Strauss explains. “It was necessary to use powder between about 15 and 60 mi-crons in order to have the flow and spread properties necessary for the machine. The upper limit of the particle size sets the minimum thickness of the as-spread layer; coarser powder requires thicker layers, which negatively impact the surface finish.”

But this is one area where progress is now being made. “Recently there has been some improvement in the powder spreading technology, allowing for the use of finer powders,” Strauss says. “Finer particles allow for a smaller build height, which produces a better surface finish. It’s still not a great surface finish, but it is an improvement.”

“Some printer brands are better equip-ped to spread these smaller metal powders,” confirms Adler, who notes that some printers use a roller instead of a blade to push the powder, providing a more even distribution. “Smaller particles can help, but surface quality also will depend on the powder alloy, how the design is positioned on the printer, and the thickness of layers one chooses in printing.”

• The second contributor to surface finish is the build orientation of the piece: Any non-horizonal surfaces would be plagued with a less than ideal finish.

“If you imagine building a cube, the top surface would be very nice because it’s a simple plane—there are no steps,” Strauss says. “But not the sides, especially if they’re not perfectly vertical.” Some of this challenge could be overcome based on the orientation of how the piece was built, but any non-horizontal surfaces would still be plagued with a series of steps, creating a less than ideal finish.

To help overcome this obstacle, Fletch-er says that his company works with customers to help them understand how to design for the technology. Given the density of the metal involved and the often unique geometries of the pieces designed for this technology, the pieces generally tend to require more supports than if you were building the same design on a 3-D resin printer. The more supports there are, the more areas on the surface that will require greater cleanup.

“If you design well and reduce the number of supports required, the surface finish goes up,” says Fletcher.

• The final factor is the fact that you’re using a laser to melt the surface of the piece. “You’re never going to have a mirror finish surface,” says Strauss. “There will always be a little bit of waviness be-cause of the molten pool of metal.”

Henrich & Denzel Helix Armreif and Ring

“It’s natural to think that tomorrow some customers will have their own printer, but the technology is still quite complex and expensive so we strongly believe that the service bureau is the easiest and fastest way.” —Luigi Benetti

The finish will also be influenced by the type of laser used to melt the metal powder. Up until recently, most metal printers on the market used a traditional red laser beam that operates at a wavelength of approximately 1,064 nanometers (nm). This is an ideal wavelength for heating platinum powder, as the metal needs around 1,000 nm to couple in easily. (Coupling is how much of the light is being absorbed by an object versus how much is being reflected. When a material ‘couples well,’ a lot of the light is being absorbed.) Gold and silver, on the other hand, are effective reflectors of 1,040 nm light; they need light of around 500 nanometers to couple in well.

This wavelength mismatch results in what Strauss calls “the fuzzies.” As he explains it, because the longer wavelength does not couple well with gold and silver (or other metals, such as copper), more power is required. Because these metals also have high thermal conductivities, the laser power is conducted to the loose powder surrounding the edges of a build. The loose powder sinters itself to the side of the part being built, making it fuzzy and further contributing to the poor surface finish of the part.

But that could soon be changing. Some metal printers are now being built with a green laser instead of the traditional red laser. Green has a shorter wavelength that allows the laser to better couple in more efficiently to metals such as gold and silver.

“It makes a more efficient build and gives a better surface finish,” says Strauss. “Now that other lasers are available, better results should happen. But whether more companies making machines will adopt it, is unknown at this time.”

Obstacles Still to Overcome

Although several small advancements in metal printing have been made, there’s still very much room for additional improvement if this technology is going to have more widespread use in the jewelry industry.

One of the issues Strauss still sees is the size of the build chamber in these ma-chines, and the amount of precious metal powder that would need to be used within these cavernous spaces. As the technology has evolved, build chambers have seemed to only get larger, which makes sense when you consider that the jewelry industry isn’t considered a primary market for printer manufacturers.

“Most of the original chambers were 10 inches by 10 inches, now they’re 3 feet by 3 feet, which doesn’t apply well to jewelry,” says Strauss. “It’s too expensive to fill that chamber [with metal powder].” Although some companies do make jewelry-specific printers, options are limited.

Strauss also notes that some companies have introduced a cartridge system that could be placed within the build chamber. The cartridge would contain the powder inside and allow a jeweler to build models in a much smaller space.

And then of course, there’s the high cost of the printers. On that field, there’s good and bad news. The good news is that prices are coming down, but the bad news is that they’re not coming down a whole lot.

Strauss notes that the cost of machines from the larger players seems to have plateaued, but that other machine makers (primarily from China) are coming onto the scene with lower-cost machines. “There are inexpensive machines available for $100k, but I don’t think they’re appropriate for jewelry at all. These are lower quality machines.”

“There’s been no dramatic decrease in price,” confirms Adler. “They’re all still pricey—six figures and up—and they’re not coming down quickly. But as the patents expire and overseas competition increases, the entry cost will most certainly come down.”

“Smaller systems will be developed and that will reduce the pricepoint as well,” adds Fletcher.

Progold Printer and Ring Group

Three-dimensional metal printing works like other 3-D printing technologies in that a CAD file is divided into a series of 2-D parallel surfaces. A metal printer spreads a thin layer of metal powder, and a laser scans a portion dictated by the 2-D CAD layer, which results in the melting of that portion of powder into a dense solid. The process then repeats—a new layer of powder is spread out, the laser makes another pass, building the model layer by layer.

While the pricepoints of these machines remain high, some printer/powder manufacturers offer leasing options for those interested in pursuing this type of manufacturing. There’s also the option of working with a service bureau to have your designs printed.

“A lot of companies that invested in powder technology offer services on their machines because they realized that not everyone can afford it, so they might as well as make jewelry for people,” says Strauss.

“It’s natural to think that tomorrow some customers will have their own print-er, but the technology is still quite complex and expensive so we strongly believe that the service bureau is the easiest and fastest way,” adds Benetti.

When Strauss thinks about where this technology could be headed in the future, he recalls the introduction of 3-D printers to the jewelry industry.

“The jewelry industry was an early adopter of resin,” he says. “Now there are jewelry stores and hobbyists with these things. I think it could follow that trajectory, but it won’t happen as fast. Prices aren’t coming down fast. And buying the metal powder is expensive. There will be a flatter growth curve than with plastic or resin printers.”

One development that Fletcher thinks could be of interest to the jewelry industry is the possibility of using ‘digital alloys’ in metal printers. He points out that his company has a portfolio of hundreds of alloys that it has made for its customers over the years, some of which can’t be rolled or annealed during traditional production, limiting their use.

“For example, we have a range of alloys such as blue, purple, and green golds that are rarely used because faults are seen in the usual production process due to the element that changes the alloy color,” he explains. “We are confident that these will work in additive manufacturing.”

Adler also thinks that custom alloys may offer the biggest application for the jewelry industry, such as new alloys that are generally harder or whiter than the alloys currently used in casting and hand fabrication. “Companies designing with alternative metals in mind will tend to thrive,” he predicts.

“I think we’ve only begun to touch the surface of what’s possible,” says Fletcher.

" title="The Power of Powder">The Power of Powder  Overcoming the obstacles of 3-D metal printing. By Shawna Kulpa

Quest for Imperfection Building flaws into CAD designs—on purpose. By Lee Krombholz

The Redrawing Board A case study on how a designer overcame a design obstacle to increase his ring’s chance of casting success. By John Shanahan

Seeing Is Believing Exploring CAD’s sculptural possibilities. By Shawna Kulpa

Selection Struggle Command tips for selecting objects in Rhino and Matrix. By Darla Alvarez, GIA Jewelry Design & Technology Instructor

Sensible Sparkle Tips for setting halos and side diamonds in CAD. By Lee Krombholz

Set to Go Tips for modeling prong settings in CAD. By Charlie Herner

Shadow Magic A step-by-step look at using CAD to creating a matching band. By Darla Alvarez

The Shop of Tomorrow The tools and technologies that may be coming soon to a workshop near you. By Shawna Kulpa

Slice and Dice Saving CAD time by repurposing cutting tools. By Darla Alvarez

Solid Visuals How jeweler Dawn Muscio uses CAD/CAM to create custom jewelry designs. By Peggy Jo Donahue

Subdivision Modeling in Action Mike Magee demonstrates how he creates freeform custom designs. By Peggy Jo Donahue

Take Two: Modifying Award-winning CAD Designs for Optimal Manufacturing Even award-winning designs that drop jaws as-rendered might have to go back to the drawing board if they want to come to life as real pieces. That was the case with two CAD designs that took home awards in the 2012 Johnson Matthey New York Sustainable Design Awards competition. Read about how these budding designers had to modify their original designs to ensure they could be successfully manufactured. By Tina Wojtkielo Snyder

Tips of the Techy Trade CAD modelers share their favorite tips for designing for manufacturability. By Steven Adler

Window Shopping Comparing the industry’s CAD/CAM options. Compiled by Shawna Kulpa


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