Linear Mold helps Michigan teen design, build watch using additive manufacturing

Han’s first experiment with Direct Metal Laser Sintering (DMLS) was “a bit disappointing,” he said, because the surface was quite rough and contained bronze, which turns skin green. “That was definitely unsuitable for jewelry, and I turned back to the high-detail resin.”

When Han came up with the idea to create a watch, he originally looked at CNC machining as his preferred method of manufacture. The big drawback was that he only wanted one watch, and very few CNC machine shops were willing to take on a one-off project. “Those who were willing charged many thousands of dollars,” Han explained. He knew that DMLS would be the most cost-efficient way of manufacturing the watch, so he continued his search for companies that did additive manufacturing.

That search turned up Linear Mold & Engineering, a Livonia, MI-based maker of plastic injection molds with extensive experience in DMLS. Linear has one of the largest custom service bureaus for DMLS in the Midwest, and offered what Han said was “the most attractive price” along with the capabilities that met his needs, including a wide variety of metals.

Brandy Badami, manager of DMLS for Linear, was a bit surprised when Han contacted the company about a “school project.” However, Badami recognized the high school’s name and decided that talking to Han would be interesting given that he was so young.

“I thought it was interesting that he’d already heard of the 3D metal printing technology,” said Badami. “I soon found out that this kid knows what he’s talking about!”

The first step was to find out what he was looking to do, so Badami went through the design stage with Han, who had individual CAD files prepared for all eight parts that he required. The parts consisted of the case, the dial, a back plate, a front plate, the bezel, two pushers, and a crown.

“That made it very easy on our end to go through the design process,” Badami said. “We then discussed the finishing options, because the DMLS process results in parts that are quite rough. Elbert planned to do some of the finishing by hand himself using the tools he had at home in his own shop in order to get the finish he wanted.”

From there Han wanted to come to Linear’s facility and observe the parts being built. Badami met with Han and his parents one Saturday at Linear’s facility in Livonia, and Han saw the parts being produced in the EOS M270 DMLS machine from 15-5 stainless steel powder.

After the parts were completed, Linear removed the support structure and performed a micro-bead blast on them to remove the roughest surface. “The surface reminds me of a sand-blasted finish, but that’s easily fixed with sandpaper and polishing compounds,” said Han. “For my next watch, Linear will additively manufacture my parts, and then finish some of the surfaces with a CNC machine. This is a prime example of how new technology and traditional machining methods can co-exist. DMLS doesn’t make traditional machining methods obsolete; it simply offers a new method of production.”

Han said that he believes that DMLS is “becoming one of the most efficient methods of manufacturing,” in terms of both time and money. “Not only is this process cheaper because of the amount of material saved versus traditional machining methods, it’s also faster and allows for many design elements that normal machining cannot accommodate,” he explained. “Hollow structures can be built, holes can be formed where traditional machining methods would fail, and sharp corners, as is characteristic of many of my designs can be made, whereas a CNC would cut out a round corner.

“Additionally, DMLS allows for a 99.9% part density, and can be post-finished as easily and with the same results as any machined part, and small details are easily made, which would be expensive or impossible to do on a traditional CNC machine.”

Han’s watch was his first “foray into watchmaking,” and won the International A’ Design Award, based in Italy. This young entrepreneur isn’t done however. He has more watches planned. He has a line of dress watches that he calls the "imperials," and he’s designing a second watch which he said has no relation to the first, other than being produced with the same manufacturing process.

Badami noted that the cost for the watch was $730. “Linear typically charges based on machine time, and the total project took eight hours for the eight pieces,” she said, adding that Linear offers a price break to schools for special projects.

“It has been exciting to work with Elbert on his school project,” Badami said. “It was great to see a young person so enthusiastic about manufacturing and technology.”