CAD/CAM: Choosing Desktop Mills

In ancient Mesopotamia, jewelry makers pounded gold into intricate shapes. As history went on, they learned how to hand carve wax models for casting custom pieces.

Today, CAD/CAM technology has revolutionized this process. Rather than spending countless hours hand carving models, jewelry makers can now focus more on the creative side of the business. As a result, they can design and produce pieces with more symmetry, detail, and imagination than ever before.

CAD/CAM technology is one of the biggest advances in the history of jewelry making. But how can we use this technology to maximize profits? After learning to design using 2-D or 3-D CAD software, it's a matter of selecting the right production tools for your jewelry, and both desktop mills (subtractive systems) and model builders (additive systems) have much to offer.

"I would have both machines, but I'd probably get the desktop mill machine first," says Russ Hyder, jewelry manufacturing arts manager for GIA. According to Hyder, model builders are ideal for producing complex, hollowed-out pieces, such as a cluster ring with a wire mounting. But he uses a Roland JWX-10 desktop mill at GIA for training purposes. "Desktop mills are less expensive, deadly accurate, and capable of producing models in castable materials."

This article will focus on desktop milling technology. (The next installment of this series on CAD/CAM will address additive CAM technology.) Mills are well suited for most jewelry pieces, including flat work (pins and earrings), large pieces (belt buckles or brooches), and three-sided rings; complex designs with undercuts and cavities may need to be produced in multiple parts and then assembled. Most mills today designed specifically for the jewelry industry are compatible with all 3-D CAD/CAM programs and accept.STL files as input.

Selecting the right mill is a big decision, so it is important to consider a few key factors before making an investment.

Ease of Use

CAD/CAM technology has been available for years. Engineers use it to design products and even create functional prototypes for pre-production testing. Most jewelers, however, lack the technical training of an engineer or industrial designer. Fortunately, desktop mills specially engineered for cutting jewelry waxes are easier to use than traditional milling machines.

"Most jewelers will benefit from a milling machine that was designed with them in mind," says Thomas Buck, president of Product Development Inc., a provider of jewelry CAD/CAM solutions in Knoxville, Tennessee. "They need a machine they can learn to use on a Sunday afternoon and start producing jewelry on Monday."

For most, training entails learning how to use the CAM software to drive the mill and learning how to install the fixtures to set up the machine. Inquire about training options and ask how long it typically takes to have the mill up and running. In addition, ask about technical support for the long term, and the associated costs.

Fixtures

On a desktop mill, the cutting tool can move on only three axes-up and down, front to back, and side to side. The fourth axis comes into play when the piece being held rotates, flipping it on end or upside down. For example, simple signets or class rings can be milled from a cylinder of wax that is rotated around the fourth axis as the tool cuts the shape. (Somemills incorporate a fifth axis, which enables users to perform even more complex undercuts.)

When milling a piece, especially a complex design with details on all sides, fixtures are critical. The fixture holds the wax and keeps it aligned throughout the entire milling process. It is important to make sure the mill has a variety of fixtures available to accommodate your needs. Do you make especially large pieces that would require a special fixture? Do you need to mill multiple pieces at one time? Before settling on a mill, make sure it comes with the fixtures you need for your designs, and ask if they are integrated with the CAM software; if they are not, the learning curve will be greater.

Build Material

If you are looking to mill only wax models, any of the jewelry-specific mills on the market will fit the bill. But if you need the flexibility to mill a variety of materials, including metals, make sure you ask what build materials the mill can handle.

Mill Design

Where your mill will make its home is another factor to consider. If you plan to house your milling machine in a workshop environment, you probably aren't as concerned about size and noise as someone who plans to run the mill in a manufacturing retail environment. For the latter, some jewelry-specific mills feature enclosures that contain wax cuttings and noise, enabling them to integrate seamlessly into a retailer's shop. Some are even making their way into the jewelry showroom as a marketing tool to show customers that a store is on the cutting edge of technology and design.