CMM-based clay model design systems

Features - Quality

Wenzel America adds milling heads to its coordinate measuring machines (CMMs) to create clay models from digital designs, then captures changes to those models to update digital files.


Despite the growing sophistication of digital design tools, if you go into any automotive design studio, you’ll still see clay models. While more products are starting in the virtual world, eventually designers need to touch, feel, and see physical representations of their work. The challenge is bridging the digital and physical design worlds. Several companies offer mills that can cut clay blocks into representations of 3D digital models. However, if designers alter the clay – adding more weight to one feature, carving a bit away from another – those changes don’t flow back to the virtual design. Some studios use hand-held scanners or coordinate measuring machines (CMMs) to capture those changes, but each can be a time-consuming process.

Drew Shemenski, president of metrology equipment supplier Wenzel America Ltd., in Wixom, Michigan, says the solution is a closed-loop system that can create the clay models and capture changes that designers make. Wenzel equipment achieves that by combining clay milling capabilities, with the scanning and measurement tools of a CMM. So, the same machine can convert a raw blank of clay into a representation of a physical design, then capture any changes made to that model.

Clay milling

“There are two types of milling for clay models – CMM-based or traditional. With a traditional mill, it’s always been a one-way process. You’re translating the 3D digital design into a physical representation,” Shemenski says. “By adding a CMM to that, it becomes a two-way process. You create that physical model from the digital design, but then you can capture changes to that clay model.”

He adds that the clay design tools came out of Wenzel’s CMM business. The company had been selling CMMs to design studios, and on a visit, engineers talked to designers about the challenges they faced. Setting up a clay model for scanning was a challenge, often requiring designers to move the clay model onto special fixtures – a step that risked damaging fine details that had been painstakingly carved into the designs.

The initial goal of adding the milling head was to eliminate those setup steps. Engineers achieved that by developing a high-precision milling head, then beefing up motors, drives, and power systems in the CMM so they could handle the weight and energy draw from the milling equipment. Engineers then added features to software tools to create the digital-to-physical-to-digital pathways.

The value of the system became clear to designers very quickly, Shemenski says. That two-way path between digital and physical designs allows studios to quickly move one version of a product to the next. Because of the investments needed to produce a new vehicle line, design studios tend to tweak every component to make sure it’s ideal before going into production.

“The average consumer has no idea how many iterations of every car, or every part of a car, designers go through before production. Our systems let companies go through iteration after iteration faster,” Shemenski explains.

Automating design

Keeping clay models on the same fixtures as they move from milling to hand alterations to scanning eliminates risk of damage and time-consuming, hand-scanning of features. The CMM producer has created several milling machines for European automotive design studios, and it offers them in North America. So far, the bulk of interest in the U.S. has come from recreational vehicle, commercial truck, all-terrain vehicle (ATV), and industrial equipment producers, Shemenski says. Those manufacturers face ergonomic design challenges, so the ability to quickly go through multiple design stages is attractive.

To further improve this iterative cycle, Wenzel has launched Wenzel DesignTec. This new division is adding to its product offering with a new line of Studio Mills that will increase the speed and capability of clay milling, while maintaining the ease of scanning and measurement in a single flexible package.

“Clay models are still essential to design, whether you’re talking about cars, motorcycles, or ATVs. Most people buy vehicles emotionally, so designers need to excite people,” Shemenski says. “Working only digitally, you lose some of that emotion. There’s no replacement for touching and seeing a part in the physical world.”

Additive technologies, such as 3D printing, are also gaining popularity in design studios for their ability to translate digital files into physical objects, and Shemenski expects sales of those systems to continue to grow. However, 3D-printed iterations still have a major drawback.

“You’re dealing with something that’s not easy to change in the physical world. You can carve away some material, but it’s very hard to do that without damaging other features,” Shemenski explains. “And you can’t add to it easily. You can’t just take more clay and mold it into the design to get a feel for the design change.”

Wenzel America Ltd.

About the author: Robert Schoenberger is the editor of TMV and can be reached at 216.393.0271 or